From 0fabbcb404b93b4224c19165fe9681ad294f5fd8 Mon Sep 17 00:00:00 2001
From: Mark Olesen <Mark.Olesen@esi-group.com>
Date: Fri, 11 Nov 2022 15:59:06 +0100
Subject: [PATCH] ENH: direct ensight output of float/double

- since ensight format is always float and also always written
  component-wise, perform the double -> float narrowing when
  extracting the components.  This reduces the amount of data
  transferred between processors.

ENH: avoid vtk/ensight parallel communication of empty messages

- since ensight writes by element type (eg, tet, hex, polyhedral) the
  individual written field sections will tend to be relatively sparse.
  Skip zero-size messages, which should help reduce some of the
  synchronization bottlenecks.

ENH: use 'data chunking' when writing ensight files in parallel

- since ensight fields are written on a per-element basis, the
  corresponding segment can become rather sparsely distributed. With
  'data chunking', we attempt to get as many send/recv messages in
  before flushing the buffer for writing. This should make the
  sequential send/recv less affected by the IO time.

ENH: allow use of an external buffer when writing ensight components

STYLE: remove last vestiges of autoPtr<ensightFile> for output routines
---
 .../test/foamToEnsight-check/Make/files       |   3 +
 .../test/foamToEnsight-check/Make/options     |  16 +
 .../foamToEnsight-check/foamToEnsight-check.C | 357 ++++++++++++++++++
 .../foamToEnsight/convertLagrangian.H         |  46 ++-
 etc/controlDict                               |  13 +-
 .../ensight/output/ensightOutputAreaField.H   |  33 +-
 .../output/ensightOutputAreaFieldTemplates.C  |   4 +-
 .../ensight/output/ensightOutputVolField.H    |  93 ++++-
 .../output/ensightOutputVolFieldTemplates.C   |  87 +++--
 src/fileFormats/ensight/file/ensightFile.C    |  41 +-
 src/fileFormats/ensight/file/ensightFile.H    |  30 +-
 .../ensight/file/ensightFileTemplates.C       |  41 +-
 .../ensight/output/ensightOutput.C            |  17 +
 .../ensight/output/ensightOutput.H            | 231 ++++++++++--
 .../ensight/output/ensightOutputFwd.H         |  78 ++++
 .../ensight/output/ensightOutputTemplates.C   | 345 +++++++++++------
 .../ensight/part/cells/ensightCells.C         |  15 +-
 .../ensight/part/cells/ensightCells.H         |   7 +-
 .../ensight/part/cells/ensightCellsI.H        |   2 +-
 .../ensight/part/faces/ensightFaces.C         |  17 +-
 .../ensight/part/faces/ensightFaces.H         |   9 +-
 .../ensight/part/faces/ensightFacesI.H        |   4 +-
 src/fileFormats/ensight/type/ensightPTraits.C |  15 +-
 src/fileFormats/ensight/type/ensightPTraits.H |  11 +-
 src/fileFormats/vtk/output/foamVtkOutput.C    |  49 +--
 .../vtk/output/foamVtkOutputTemplates.C       | 296 +++++++++------
 .../utilities/ensightWrite/ensightWrite.C     |  33 +-
 .../utilities/ensightWrite/ensightWrite.H     |  34 +-
 ...ghtWriteTemplates.C => ensightWriteImpl.C} |   6 +-
 .../conversion/ensight/ensightOutputCloud.C   | 148 +++++---
 .../conversion/ensight/ensightOutputCloud.H   |  44 ++-
 .../ensight/ensightOutputCloudTemplates.C     |  78 ++--
 .../writers/ensight/ensightCoordSetWriter.C   |  12 +-
 33 files changed, 1698 insertions(+), 517 deletions(-)
 create mode 100644 applications/test/foamToEnsight-check/Make/files
 create mode 100644 applications/test/foamToEnsight-check/Make/options
 create mode 100644 applications/test/foamToEnsight-check/foamToEnsight-check.C
 create mode 100644 src/fileFormats/ensight/output/ensightOutputFwd.H
 rename src/functionObjects/utilities/ensightWrite/{ensightWriteTemplates.C => ensightWriteImpl.C} (92%)

diff --git a/applications/test/foamToEnsight-check/Make/files b/applications/test/foamToEnsight-check/Make/files
new file mode 100644
index 0000000000..d5b94d1fe7
--- /dev/null
+++ b/applications/test/foamToEnsight-check/Make/files
@@ -0,0 +1,3 @@
+foamToEnsight-check.C
+
+EXE = $(FOAM_USER_APPBIN)/foamToEnsight-check
diff --git a/applications/test/foamToEnsight-check/Make/options b/applications/test/foamToEnsight-check/Make/options
new file mode 100644
index 0000000000..7fd9abdcb7
--- /dev/null
+++ b/applications/test/foamToEnsight-check/Make/options
@@ -0,0 +1,16 @@
+EXE_INC = \
+    -I$(LIB_SRC)/finiteVolume/lnInclude \
+    -I$(LIB_SRC)/finiteArea/lnInclude \
+    -I$(LIB_SRC)/fileFormats/lnInclude \
+    -I$(LIB_SRC)/meshTools/lnInclude \
+    -I$(LIB_SRC)/conversion/lnInclude \
+    -I$(LIB_SRC)/lagrangian/intermediate/lnInclude
+
+EXE_LIBS = \
+    -lfiniteVolume \
+    -lfiniteArea \
+    -lfileFormats \
+    -lmeshTools \
+    -lconversion \
+    -llagrangianIntermediate \
+    -lgenericPatchFields
diff --git a/applications/test/foamToEnsight-check/foamToEnsight-check.C b/applications/test/foamToEnsight-check/foamToEnsight-check.C
new file mode 100644
index 0000000000..8759fcf8db
--- /dev/null
+++ b/applications/test/foamToEnsight-check/foamToEnsight-check.C
@@ -0,0 +1,357 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | www.openfoam.com
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+    Copyright (C) 2022 OpenCFD Ltd.
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Application
+    foamToEnsight-check
+
+Description
+    Check data sizes for conversion to ensight format.
+
+\*---------------------------------------------------------------------------*/
+
+#include "argList.H"
+#include "timeSelector.H"
+#include "IOobjectList.H"
+#include "IOmanip.H"
+#include "OFstream.H"
+#include "Pstream.H"
+#include "HashOps.H"
+#include "regionProperties.H"
+
+#include "fvc.H"
+#include "faMesh.H"
+#include "fvMesh.H"
+
+// file-format/conversion
+#include "ensightFaMesh.H"
+#include "ensightMesh.H"
+
+using namespace Foam;
+
+
+void printStats(const FixedList<label, 3>& stats, const char *what = "")
+{
+    Info<< what << "max-comm: "<< stats[0] << nl
+        << what << "max-size: "<< stats[1] << nl
+        << what << "off-proc: "<< stats[2] << nl;
+}
+
+
+template<class EnsightPartType>
+FixedList<label, 3> printPartInfo
+(
+    const EnsightPartType& part,
+    int verbose = 0
+)
+{
+    Info<< "part: " << part.name().c_str() << nl
+        << "    size: "
+        << (Pstream::parRun() ? part.total() : part.size())
+        << " (";
+
+    FixedList<label, 3> stats(Zero);
+
+    label& maxComm = stats[0];
+    label& maxSize = stats[1];
+    label& totNonLocalSize = stats[2];
+
+    for (int typei=0; typei < EnsightPartType::nTypes; ++typei)
+    {
+        const auto etype = typename EnsightPartType::elemType(typei);
+
+        if (typei) Info<< ' ';
+        Info<< EnsightPartType::elemNames[etype] << ": "
+            << (Pstream::parRun() ? part.total(etype) : part.size(etype));
+
+        label elemCount = part.size(etype);
+        label commCount = (Pstream::master() ? label(0) : elemCount);
+        label nonLocalCount = commCount;
+
+        if (Pstream::parRun())
+        {
+            reduce(elemCount, maxOp<label>());
+            reduce(commCount, maxOp<label>());
+
+            reduce(nonLocalCount, sumOp<label>());
+        }
+
+        maxComm = max(maxComm, commCount);
+        maxSize = max(maxSize, elemCount);
+        totNonLocalSize = max(totNonLocalSize, nonLocalCount);
+    }
+    Info<< ")" << endl;
+
+    if (verbose && Pstream::parRun() && part.total())
+    {
+        for (int typei=0; typei < EnsightPartType::nTypes; ++typei)
+        {
+            const auto etype = typename EnsightPartType::elemType(typei);
+
+            label elemCount = part.size(etype);
+            label totCount = part.total(etype);
+
+            Info<< "    "
+                << EnsightPartType::elemNames[etype] << ": "
+                << totCount;
+
+            if (totCount)
+            {
+                labelList sizes(UPstream::listGatherValues(elemCount));
+
+                Info<< "  ";
+                sizes.writeList(Info);
+            }
+
+            Info<< endl;
+        }
+    }
+
+    printStats(stats, "    ");
+
+    return stats;
+}
+
+
+void printInfo(const ensightMesh& mesh, int verbose = 0)
+{
+    FixedList<label, 3> cellStats(Zero);
+    FixedList<label, 3> faceStats(Zero);
+
+    for (const auto& iter : mesh.cellZoneParts().sorted())
+    {
+        FixedList<label, 3> stats = printPartInfo(iter.val(), verbose);
+
+        for (label i=0; i < 3; ++i)
+        {
+            cellStats[i] = max(cellStats[i], stats[i]);
+        }
+    }
+
+    for (const auto& iter : mesh.faceZoneParts().sorted())
+    {
+        FixedList<label, 3> stats = printPartInfo(iter.val(), verbose);
+
+        for (label i=0; i < 3; ++i)
+        {
+            faceStats[i] = max(faceStats[i], stats[i]);
+        }
+    }
+
+    for (const auto& iter : mesh.boundaryParts().sorted())
+    {
+        FixedList<label, 3> stats = printPartInfo(iter.val(), verbose);
+
+        for (label i=0; i < 3; ++i)
+        {
+            faceStats[i] = max(faceStats[i], stats[i]);
+        }
+    }
+
+    Info<< nl
+        << "===============" << nl;
+    printStats(cellStats, "cell ");
+
+    Info<< nl;
+    printStats(faceStats, "face ");
+
+    Info<< "===============" << endl;
+}
+
+
+void printInfo(const ensightFaMesh& mesh, int verbose = 0)
+{
+    printPartInfo(mesh.areaPart());
+}
+
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+int main(int argc, char *argv[])
+{
+    argList::addNote
+    (
+        "Check data sizes for conversion of OpenFOAM to Ensight format"
+    );
+    // timeSelector::addOptions();
+
+    // Less frequently used - reduce some clutter
+    argList::setAdvanced("decomposeParDict");
+
+    argList::addVerboseOption("Additional verbosity");
+
+    #include "addAllRegionOptions.H"
+
+    argList::addBoolOption
+    (
+        "no-boundary",  // noPatches
+        "Suppress writing any patches"
+    );
+    argList::addBoolOption
+    (
+        "no-internal",
+        "Suppress writing the internal mesh"
+    );
+    argList::addBoolOption
+    (
+        "no-cellZones",
+        "Suppress writing any cellZones"
+    );
+    argList::addBoolOption
+    (
+        "no-finite-area",
+        "Suppress output of finite-area mesh/fields",
+        true  // mark as an advanced option
+    );
+
+    #include "setRootCase.H"
+
+    // ------------------------------------------------------------------------
+    // Configuration
+
+    const int optVerbose = args.verbose();
+    const bool doBoundary    = !args.found("no-boundary");
+    const bool doInternal    = !args.found("no-internal");
+    const bool doCellZones   = !args.found("no-cellZones");
+    const bool doFiniteArea  = !args.found("no-finite-area");
+
+    ensightMesh::options writeOpts;
+    writeOpts.useBoundaryMesh(doBoundary);
+    writeOpts.useInternalMesh(doInternal);
+    writeOpts.useCellZones(doCellZones);
+
+    // ------------------------------------------------------------------------
+
+    #include "createTime.H"
+
+    instantList timeDirs = timeSelector::select0(runTime, args);
+
+    // Handle -allRegions, -regions, -region
+    #include "getAllRegionOptions.H"
+
+    // ------------------------------------------------------------------------
+
+    #include "createNamedMeshes.H"
+
+    // ------------------------------------------------------------------------
+    /// #include "createMeshAccounting.H"
+
+    PtrList<ensightMesh> ensightMeshes(regionNames.size());
+    PtrList<faMesh> meshesFa(regionNames.size());
+    PtrList<ensightFaMesh> ensightMeshesFa(regionNames.size());
+
+    forAll(regionNames, regioni)
+    {
+        const fvMesh& mesh = meshes[regioni];
+
+        ensightMeshes.set
+        (
+            regioni,
+            new ensightMesh(mesh, writeOpts)
+        );
+        ensightMeshes[regioni].verbose(optVerbose);
+
+
+        if (doFiniteArea)
+        {
+            autoPtr<faMesh> faMeshPtr(faMesh::TryNew(mesh));
+
+            if (faMeshPtr)
+            {
+                meshesFa.set(regioni, std::move(faMeshPtr));
+
+                ensightMeshesFa.set
+                (
+                    regioni,
+                    new ensightFaMesh(meshesFa[regioni])
+                );
+                ensightMeshesFa[regioni].verbose(optVerbose);
+            }
+        }
+    }
+
+    // ------------------------------------------------------------------------
+
+
+    if (Pstream::master())
+    {
+        Info<< "Checking " << timeDirs.size() << " time steps" << nl;
+    }
+
+    forAll(timeDirs, timei)
+    {
+        runTime.setTime(timeDirs[timei], timei);
+
+        forAll(regionNames, regioni)
+        {
+            const word& regionName = regionNames[regioni];
+            // const word& regionDir = polyMesh::regionName(regionName);
+
+            auto& mesh = meshes[regioni];
+
+            polyMesh::readUpdateState meshState = mesh.readUpdate();
+            const bool moving = (meshState != polyMesh::UNCHANGED);
+
+            auto& ensMesh = ensightMeshes[regioni];
+
+            // Finite-area (can be missing)
+            auto* ensFaMeshPtr = ensightMeshesFa.get(regioni);
+
+            if (moving)
+            {
+                ensMesh.expire();
+                ensMesh.correct();
+
+                if (ensFaMeshPtr)
+                {
+                    ensFaMeshPtr->expire();
+                    ensFaMeshPtr->correct();
+                }
+            }
+
+            if (moving || timei == 0)  // report
+            {
+                if (regionNames.size() > 1)
+                {
+                    Info<< "region=" << regionName << nl;
+                }
+
+                printInfo(ensMesh, optVerbose);
+
+                if (ensFaMeshPtr)
+                {
+                    printInfo(*ensFaMeshPtr, optVerbose);
+                }
+            }
+        }
+    }
+
+    Info<< "\nEnd"<< nl << endl;
+
+    return 0;
+}
+
+
+// ************************************************************************* //
diff --git a/applications/utilities/postProcessing/dataConversion/foamToEnsight/convertLagrangian.H b/applications/utilities/postProcessing/dataConversion/foamToEnsight/convertLagrangian.H
index 45ee1ee64a..cff8b5cb05 100644
--- a/applications/utilities/postProcessing/dataConversion/foamToEnsight/convertLagrangian.H
+++ b/applications/utilities/postProcessing/dataConversion/foamToEnsight/convertLagrangian.H
@@ -45,10 +45,10 @@ if (doLagrangian)
 
             ensightOutput::writeCloudPositions
             (
+                os.ref(),
                 mesh,
                 cloudName,
-                cloudExists,
-                os
+                cloudExists
             );
 
             Info<< " positions";
@@ -86,26 +86,34 @@ if (doLagrangian)
             }
 
             bool wrote = false;
-            if (fieldType == scalarIOField::typeName)
+            do
             {
-                autoPtr<ensightFile> os =
-                    ensCase.newCloudData<scalar>(cloudName, fieldName);
+                #undef  ensight_WRITE_CLOUD_FIELD
+                #define ensight_WRITE_CLOUD_FIELD(PrimitiveType)              \
+                                                                              \
+                if (fieldType == IOField<PrimitiveType>::typeName)            \
+                {                                                             \
+                    autoPtr<ensightFile> os =                                 \
+                        ensCase.newCloudData<PrimitiveType>                   \
+                        (                                                     \
+                            cloudName,                                        \
+                            fieldName                                         \
+                        );                                                    \
+                                                                              \
+                    wrote = ensightOutput::readWriteCloudField<PrimitiveType> \
+                    (                                                         \
+                        os.ref(),                                             \
+                        fieldObject,                                          \
+                        fieldExists                                           \
+                    );                                                        \
+                    break;                                                    \
+                }
 
-                wrote = ensightOutput::writeCloudField<scalar>
-                (
-                    fieldObject, fieldExists, os
-                );
-            }
-            else if (fieldType == vectorIOField::typeName)
-            {
-                autoPtr<ensightFile> os =
-                    ensCase.newCloudData<vector>(cloudName, fieldName);
+                ensight_WRITE_CLOUD_FIELD(scalar);
+                ensight_WRITE_CLOUD_FIELD(vector);
 
-                wrote = ensightOutput::writeCloudField<vector>
-                (
-                    fieldObject, fieldExists, os
-                );
-            }
+                #undef ensight_WRITE_CLOUD_FIELD
+            } while (false);
 
             if (wrote)
             {
diff --git a/etc/controlDict b/etc/controlDict
index 2a2b04713f..2cbd7bdec0 100644
--- a/etc/controlDict
+++ b/etc/controlDict
@@ -1,7 +1,7 @@
 /*--------------------------------*- C++ -*----------------------------------*\
 | =========                 |                                                 |
 | \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
-|  \\    /   O peration     | Version:  v2206                                 |
+|  \\    /   O peration     | Version:  v2212                                 |
 |   \\  /    A nd           | Website:  www.openfoam.com                      |
 |    \\/     M anipulation  |                                                 |
 \*---------------------------------------------------------------------------*/
@@ -118,7 +118,14 @@ OptimisationSwitches
     //  Default: 1e9
     maxMasterFileBufferSize 1e9;
 
-    commsType       nonBlocking; //scheduled; //blocking;
+    // Upper limit when bundling off-processor field transfers (ensight).
+    // for component-wise transfer (uses float: 4 bytes)
+    // Eg, 5M for 50 ranks of 100k cells
+    ensight.maxChunk 5000000;
+
+
+    // Default communication type (nonBlocking | scheduled | blocking);
+    commsType       nonBlocking;
     floatTransfer   0;
     nProcsSimpleSum 0;
 
@@ -136,6 +143,7 @@ OptimisationSwitches
     // global reduction, even if multi-pass is not needed)
     maxCommsSize    0;
 
+
     // Trap floating point exception.
     // Can override with FOAM_SIGFPE env variable (true|false)
     trapFpe         1;
@@ -539,6 +547,7 @@ DebugSwitches
     empty               0;
     engineMesh          0;
     enrichedPatch       0;
+    ensight             0;
     epsilonWallFunction 0;
     errorDrivenRefinement   0;
     evaporationModel    0;
diff --git a/src/conversion/ensight/output/ensightOutputAreaField.H b/src/conversion/ensight/output/ensightOutputAreaField.H
index 37618cca6d..416c764ca3 100644
--- a/src/conversion/ensight/output/ensightOutputAreaField.H
+++ b/src/conversion/ensight/output/ensightOutputAreaField.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2021 OpenCFD Ltd.
+    Copyright (C) 2021-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -31,8 +31,8 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef ensightOutputAreaField_H
-#define ensightOutputAreaField_H
+#ifndef Foam_ensightOutput_areaField_H
+#define Foam_ensightOutput_areaField_H
 
 #include "ensightOutput.H"
 #include "ensightFaces.H"
@@ -57,12 +57,39 @@ namespace ensightOutput
 template<class Type>
 bool writeAreaField
 (
+    //! Component scratch buffer
+    ensightOutput::floatBufferType& scratch,
+
+    //! Output file (must be valid on master)
     ensightFile& os,
+
+    //! The field content to be written
     const GeometricField<Type, faPatchField, areaMesh>& fld,
+
+    //! The addressing into the field
     const ensightFaMesh& ensMesh
 );
 
 
+//- Write finite-area field component-wise
+template<class Type>
+bool writeAreaField
+(
+    //! Output file (must be valid on master)
+    ensightFile& os,
+
+    //! The field content to be written
+    const GeometricField<Type, faPatchField, areaMesh>& fld,
+
+    //! The addressing into the field
+    const ensightFaMesh& ensMesh
+)
+{
+    ensightOutput::floatBufferType scratch;
+    return ensightOutput::writeAreaField(scratch, os, fld, ensMesh);
+}
+
+
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 } // End namespace ensightOutput
diff --git a/src/conversion/ensight/output/ensightOutputAreaFieldTemplates.C b/src/conversion/ensight/output/ensightOutputAreaFieldTemplates.C
index aaccbd3cc2..4b7d2e84b1 100644
--- a/src/conversion/ensight/output/ensightOutputAreaFieldTemplates.C
+++ b/src/conversion/ensight/output/ensightOutputAreaFieldTemplates.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2021 OpenCFD Ltd.
+    Copyright (C) 2021-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -34,6 +34,7 @@ License
 template<class Type>
 bool Foam::ensightOutput::writeAreaField
 (
+    ensightOutput::floatBufferType& scratch,
     ensightFile& os,
     const GeometricField<Type, faPatchField, areaMesh>& fld,
     const ensightFaMesh& ensMesh
@@ -45,6 +46,7 @@ bool Foam::ensightOutput::writeAreaField
     {
         ensightOutput::Detail::writeFaceLocalField
         (
+            scratch,
             os,
             fld,
             ensMesh.areaPart(),
diff --git a/src/conversion/ensight/output/ensightOutputVolField.H b/src/conversion/ensight/output/ensightOutputVolField.H
index 7309103d4d..1c489e11c5 100644
--- a/src/conversion/ensight/output/ensightOutputVolField.H
+++ b/src/conversion/ensight/output/ensightOutputVolField.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2020 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -31,8 +31,8 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef ensightOutputVolField_H
-#define ensightOutputVolField_H
+#ifndef Foam_ensightOutput_volField_H
+#define Foam_ensightOutput_volField_H
 
 #include "ensightOutput.H"
 #include "ensightFaces.H"
@@ -58,30 +58,115 @@ namespace ensightOutput
 template<class Type>
 bool writeVolField
 (
+    //! Component scratch buffer
+    ensightOutput::floatBufferType& scratch,
+
+    //! Output file (must be valid on master)
     ensightFile& os,
+
+    //! The field content to be written
     const GeometricField<Type, fvPatchField, volMesh>& vf,
+
+    //! The addressing (element-wise) into the field
     const ensightMesh& ensMesh
 );
 
+//- Write volume field component-wise
+template<class Type>
+bool writeVolField
+(
+    //! Output file (must be valid on master)
+    ensightFile& os,
+
+    //! The field content to be written
+    const GeometricField<Type, fvPatchField, volMesh>& vf,
+
+    //! The addressing (element-wise) into the field
+    const ensightMesh& ensMesh
+)
+{
+    ensightOutput::floatBufferType scratch;
+    return ensightOutput::writeVolField<Type>(scratch, os, vf, ensMesh);
+}
 
 //- Write volume field component-wise, optionally forcing interpolation
 template<class Type>
 bool writeVolField
 (
+    //! Component scratch buffer
+    ensightOutput::floatBufferType& scratch,
+
+    //! Output file (must be valid on master)
     ensightFile& os,
+
+    //! The field content to be written
     const GeometricField<Type, fvPatchField, volMesh>& vf,
+
+    //! The addressing (element-wise) into the field
     const ensightMesh& ensMesh,
+
+    //! Interpolate values to points
     const bool nodeValues
 );
 
+//- Write volume field component-wise, optionally forcing interpolation
+template<class Type>
+bool writeVolField
+(
+    //! Output file (must be valid on master)
+    ensightFile& os,
+
+    //! The field content to be written
+    const GeometricField<Type, fvPatchField, volMesh>& vf,
+
+    //! The addressing (element-wise) into the field
+    const ensightMesh& ensMesh,
+
+    //! Interpolate values to points
+    const bool nodeValues
+)
+{
+    ensightOutput::floatBufferType scratch;
+    return ensightOutput::writeVolField<Type>
+    (
+        scratch, os, vf, ensMesh, nodeValues
+    );
+}
+
+//- Write point field component-wise
+template<class Type>
+bool writePointField
+(
+    //! Component scratch buffer
+    ensightOutput::floatBufferType& scratch,
+
+    //! Output file (must be valid on master)
+    ensightFile& os,
+
+    //! The field content to be written
+    const GeometricField<Type, pointPatchField, pointMesh>& pf,
+
+    //! The addressing (element-wise) into the field
+    const ensightMesh& ensMesh
+);
+
 //- Write point field component-wise
 template<class Type>
 bool writePointField
 (
+    //! Output file (must be valid on master)
     ensightFile& os,
+
+    //! The field content to be written
     const GeometricField<Type, pointPatchField, pointMesh>& pf,
+
+    //! The addressing (element-wise) into the field
     const ensightMesh& ensMesh
-);
+)
+{
+    ensightOutput::floatBufferType scratch;
+    return ensightOutput::writePointField<Type>(scratch, os, pf, ensMesh);
+}
 
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
diff --git a/src/conversion/ensight/output/ensightOutputVolFieldTemplates.C b/src/conversion/ensight/output/ensightOutputVolFieldTemplates.C
index d7f07621ca..b940f11d23 100644
--- a/src/conversion/ensight/output/ensightOutputVolFieldTemplates.C
+++ b/src/conversion/ensight/output/ensightOutputVolFieldTemplates.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -40,6 +40,7 @@ License
 template<class Type>
 bool Foam::ensightOutput::writeVolField
 (
+    ensightOutput::floatBufferType& scratch,
     ensightFile& os,
     const GeometricField<Type, fvPatchField, volMesh>& vf,
     const ensightMesh& ensMesh
@@ -54,13 +55,12 @@ bool Foam::ensightOutput::writeVolField
     const Map<ensightFaces>& faceZoneParts = ensMesh.faceZoneParts();
     const Map<ensightFaces>& boundaryParts = ensMesh.boundaryParts();
 
-
     // Write internalMesh and cellZones - sorted by index
     for (const label zoneId : cellZoneParts.sortedToc())
     {
         const ensightCells& part = cellZoneParts[zoneId];
 
-        ensightOutput::writeField(os, vf, part, parallel);
+        ensightOutput::writeField(scratch, os, vf, part, parallel);
     }
 
 
@@ -88,6 +88,7 @@ bool Foam::ensightOutput::writeVolField
 
         ensightOutput::writeField
         (
+            scratch,
             os,
             vf.boundaryField()[patchId],
             localPart,
@@ -170,7 +171,7 @@ bool Foam::ensightOutput::writeVolField
         // - boundary faces use the corresponding patch value
 
         // Local copy of the field
-        values.resize(part.size());
+        values.resize_nocopy(part.size());
         values = Zero;
 
         auto valIter = values.begin();
@@ -189,7 +190,10 @@ bool Foam::ensightOutput::writeVolField
 
         // The field is already in the proper element order
         // - just need its corresponding sub-fields
-        ensightOutput::Detail::writeFaceSubField(os, values, part, parallel);
+        ensightOutput::Detail::writeFaceSubField
+        (
+            scratch, os, values, part, parallel
+        );
     }
 
     return true;
@@ -199,6 +203,7 @@ bool Foam::ensightOutput::writeVolField
 template<class Type>
 bool Foam::ensightOutput::writePointField
 (
+    ensightOutput::floatBufferType& scratch,
     ensightFile& os,
     const GeometricField<Type, pointPatchField, pointMesh>& pf,
     const ensightMesh& ensMesh
@@ -219,16 +224,28 @@ bool Foam::ensightOutput::writePointField
     {
         const ensightCells& part = cellZoneParts[zoneId];
 
+        labelList uniquePointLabels;
+        part.uniqueMeshPoints(mesh, uniquePointLabels, parallel);
+
         if (Pstream::master())
         {
             os.beginPart(part.index());
         }
 
-        labelList uniquePointLabels;
-        part.uniqueMeshPoints(mesh, uniquePointLabels, parallel);
+        // Skip if empty
+        if
+        (
+            parallel
+          ? returnReduceAnd(uniquePointLabels.empty())
+          : uniquePointLabels.empty()
+        )
+        {
+            continue;
+        }
 
         ensightOutput::Detail::writeFieldComponents
         (
+            scratch,
             os,
             ensightFile::coordinates,
             UIndirectList<Type>(pf.internalField(), uniquePointLabels),
@@ -244,13 +261,24 @@ bool Foam::ensightOutput::writePointField
     {
         const ensightFaces& part = boundaryParts[patchId];
 
+        labelList uniquePointLabels;
+        part.uniqueMeshPoints(mesh, uniquePointLabels, parallel);
+
         if (Pstream::master())
         {
             os.beginPart(part.index());
         }
 
-        labelList uniquePointLabels;
-        part.uniqueMeshPoints(mesh, uniquePointLabels, parallel);
+        // Skip if empty
+        if
+        (
+            parallel
+          ? returnReduceAnd(uniquePointLabels.empty())
+          : uniquePointLabels.empty()
+        )
+        {
+            continue;
+        }
 
         const auto& bfld = pf.boundaryField()[patchId];
 
@@ -272,6 +300,7 @@ bool Foam::ensightOutput::writePointField
 
             ensightOutput::Detail::writeFieldComponents
             (
+                scratch,
                 os,
                 ensightFile::coordinates,
                 UIndirectList<Type>(*vpp, uniquePointLabels),
@@ -282,6 +311,7 @@ bool Foam::ensightOutput::writePointField
         {
             ensightOutput::Detail::writeFieldComponents
             (
+                scratch,
                 os,
                 ensightFile::coordinates,
                 UIndirectList<Type>(pf.internalField(), uniquePointLabels),
@@ -297,26 +327,36 @@ bool Foam::ensightOutput::writePointField
     {
         const ensightFaces& part = faceZoneParts[zoneId];
 
+        labelList uniquePointLabels;
+        part.uniqueMeshPoints(mesh, uniquePointLabels, parallel);
+
         if (Pstream::master())
         {
             os.beginPart(part.index());
         }
 
+        // Skip if empty
+        if
+        (
+            parallel
+          ? returnReduceAnd(uniquePointLabels.empty())
+          : uniquePointLabels.empty()
+        )
+        {
+            continue;
+        }
+
         // CAVEAT - does not properly handle valuePointPatchField,
         // uses internalField only
 
-        {
-            labelList uniquePointLabels;
-            part.uniqueMeshPoints(mesh, uniquePointLabels, parallel);
-
-            ensightOutput::Detail::writeFieldComponents
-            (
-                os,
-                ensightFile::coordinates,
-                UIndirectList<Type>(pf.internalField(), uniquePointLabels),
-                parallel
-            );
-        }
+        ensightOutput::Detail::writeFieldComponents
+        (
+            scratch,
+            os,
+            ensightFile::coordinates,
+            UIndirectList<Type>(pf.internalField(), uniquePointLabels),
+            parallel
+        );
     }
 
     return true;
@@ -328,6 +368,7 @@ bool Foam::ensightOutput::writePointField
 template<class Type>
 bool Foam::ensightOutput::writeVolField
 (
+    ensightOutput::floatBufferType& scratch,
     ensightFile& os,
     const GeometricField<Type, fvPatchField, volMesh>& vf,
     const ensightMesh& ensMesh,
@@ -343,10 +384,10 @@ bool Foam::ensightOutput::writeVolField
         pfld.ref().checkOut();
         pfld.ref().rename(vf.name());
 
-        return ensightOutput::writePointField<Type>(os, pfld, ensMesh);
+        return ensightOutput::writePointField<Type>(scratch, os, pfld, ensMesh);
     }
 
-    return ensightOutput::writeVolField<Type>(os, vf, ensMesh);
+    return ensightOutput::writeVolField<Type>(scratch, os, vf, ensMesh);
 }
 
 
diff --git a/src/fileFormats/ensight/file/ensightFile.C b/src/fileFormats/ensight/file/ensightFile.C
index bd39b34b0a..19e9eb0b46 100644
--- a/src/fileFormats/ensight/file/ensightFile.C
+++ b/src/fileFormats/ensight/file/ensightFile.C
@@ -43,9 +43,23 @@ const char* const Foam::ensightFile::coordinates = "coordinates";
 
 // * * * * * * * * * * * * * Static Member Functions * * * * * * * * * * * * //
 
-bool Foam::ensightFile::hasUndef(const UList<scalar>& field)
+bool Foam::ensightFile::hasUndef(const UList<float>& field)
 {
-    for (const scalar& val : field)
+    for (const float val : field)
+    {
+        if (std::isnan(val))
+        {
+            return true;
+        }
+    }
+
+    return true;
+}
+
+
+bool Foam::ensightFile::hasUndef(const UList<double>& field)
+{
+    for (const double val : field)
     {
         if (std::isnan(val))
         {
@@ -354,15 +368,32 @@ void Foam::ensightFile::writeList(const UList<label>& field)
 {
     for (const label val : field)
     {
-        write(scalar(val));
+        write(float(val));
         newline();
     }
 }
 
 
-void Foam::ensightFile::writeList(const UList<scalar>& field)
+void Foam::ensightFile::writeList(const UList<float>& field)
 {
-    for (const scalar val : field)
+    for (const float val : field)
+    {
+        if (std::isnan(val))
+        {
+            writeUndef();
+        }
+        else
+        {
+            write(val);
+        }
+        newline();
+    }
+}
+
+
+void Foam::ensightFile::writeList(const UList<double>& field)
+{
+    for (const double val : field)
     {
         if (std::isnan(val))
         {
diff --git a/src/fileFormats/ensight/file/ensightFile.H b/src/fileFormats/ensight/file/ensightFile.H
index 6f63148fe2..b35dd97558 100644
--- a/src/fileFormats/ensight/file/ensightFile.H
+++ b/src/fileFormats/ensight/file/ensightFile.H
@@ -228,26 +228,42 @@ public:
         //  Adds newline after each value (ascii stream)
         void writeList(const UList<label>& field);
 
-        //- Write a list of floating-point as "%12.5e" or as binary
-        //- (double is narrowed to float).
+        //- Write a list of floats as "%12.5e" or as binary.
         //  Adds newline after each value (ascii stream)
-        void writeList(const UList<scalar>& field);
+        void writeList(const UList<float>& field);
 
-        //- Write an indirect list of scalars as "%12.5e" or as binary
+        //- Write a list of double as "%12.5e" or as binary.
+        //- (double is narrowed to float)
+        //  Adds newline after each value (ascii stream)
+        void writeList(const UList<double>& field);
+
+        //- Write an indirect list of float as "%12.5e" or as binary
+        //  Adds newline after each value (ascii stream)
+        template<class Addr>
+        void writeList(const IndirectListBase<float, Addr>& field);
+
+        //- Write an indirect list of double as "%12.5e" or as binary.
         //- (double is narrowed to float)
         //  Adds newline after each value (ascii stream)
         template<class Addr>
-        void writeList(const IndirectListBase<scalar, Addr>& field);
+        void writeList(const IndirectListBase<double, Addr>& field);
 
 
     // Other Methods
 
         //- Check for any NaN in the field
-        static bool hasUndef(const UList<scalar>& field);
+        static bool hasUndef(const UList<float>& field);
+
+        //- Check for any NaN in the field
+        static bool hasUndef(const UList<double>& field);
 
         //- Check for any NaN in the field
         template<class Addr>
-        static bool hasUndef(const IndirectListBase<scalar, Addr>& field);
+        static bool hasUndef(const IndirectListBase<float, Addr>& field);
+
+        //- Check for any NaN in the field
+        template<class Addr>
+        static bool hasUndef(const IndirectListBase<double, Addr>& field);
 };
 
 
diff --git a/src/fileFormats/ensight/file/ensightFileTemplates.C b/src/fileFormats/ensight/file/ensightFileTemplates.C
index 5603f95dcf..7ce8ff147e 100644
--- a/src/fileFormats/ensight/file/ensightFileTemplates.C
+++ b/src/fileFormats/ensight/file/ensightFileTemplates.C
@@ -28,9 +28,24 @@ License
 // * * * * * * * * * * * * * Static Member Functions * * * * * * * * * * * * //
 
 template<class Addr>
-bool Foam::ensightFile::hasUndef(const IndirectListBase<scalar, Addr>& field)
+bool Foam::ensightFile::hasUndef(const IndirectListBase<float, Addr>& field)
 {
-    for (const scalar val : field)
+    for (const float val : field)
+    {
+        if (std::isnan(val))
+        {
+            return true;
+        }
+    }
+
+    return true;
+}
+
+
+template<class Addr>
+bool Foam::ensightFile::hasUndef(const IndirectListBase<double, Addr>& field)
+{
+    for (const double val : field)
     {
         if (std::isnan(val))
         {
@@ -56,9 +71,27 @@ void Foam::ensightFile::writeLabels(const IndirectListBase<label, Addr>& list)
 
 
 template<class Addr>
-void Foam::ensightFile::writeList(const IndirectListBase<scalar, Addr>& field)
+void Foam::ensightFile::writeList(const IndirectListBase<float, Addr>& field)
 {
-    for (const scalar val : field)
+    for (const float val : field)
+    {
+        if (std::isnan(val))
+        {
+            writeUndef();
+        }
+        else
+        {
+            write(val);
+        }
+        newline();
+    }
+}
+
+
+template<class Addr>
+void Foam::ensightFile::writeList(const IndirectListBase<double, Addr>& field)
+{
+    for (const double val : field)
     {
         if (std::isnan(val))
         {
diff --git a/src/fileFormats/ensight/output/ensightOutput.C b/src/fileFormats/ensight/output/ensightOutput.C
index d2d8eb007a..80d73531bb 100644
--- a/src/fileFormats/ensight/output/ensightOutput.C
+++ b/src/fileFormats/ensight/output/ensightOutput.C
@@ -32,6 +32,23 @@ License
 #include "polyMesh.H"
 #include "ListOps.H"
 #include "manifoldCellsMeshObject.H"
+#include "debug.H"
+#include "defineDebugSwitch.H"
+#include "registerSwitch.H"
+
+// * * * * * * * * * * * * * * * * Globals * * * * * * * * * * * * * * * * * //
+
+defineDebugSwitchWithName(Foam::ensightOutput, "ensight", 0);
+
+registerDebugSwitchWithName(Foam::ensightOutput, ensightOutput, "ensight");
+
+int Foam::ensightOutput::maxChunk_
+(
+    Foam::debug::optimisationSwitch("ensight.maxChunk", 0)
+);
+
+registerOptSwitch("ensight.maxChunk", int, Foam::ensightOutput::maxChunk_);
+
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
diff --git a/src/fileFormats/ensight/output/ensightOutput.H b/src/fileFormats/ensight/output/ensightOutput.H
index a9833d2de1..4c26ff69dc 100644
--- a/src/fileFormats/ensight/output/ensightOutput.H
+++ b/src/fileFormats/ensight/output/ensightOutput.H
@@ -38,6 +38,7 @@ SourceFiles
 #ifndef Foam_ensightOutput_H
 #define Foam_ensightOutput_H
 
+#include "ensightOutputFwd.H"
 #include "ensightFile.H"
 #include "ensightGeoFile.H"
 #include "ensightCells.H"
@@ -186,7 +187,8 @@ void writeFaceConnectivity
     const ensightFaces::elemType etype,
     const label nTotal,
     const UIndirectList<face>& faces,
-    bool parallel               //!< Collective write?
+    //! Prefer collective write?
+    bool parallel
 );
 
 
@@ -197,7 +199,8 @@ void writeFaceConnectivity
     const ensightFaces::elemType etype,
     const label nTotal,
     const faceUList& faces,
-    bool parallel               //!< Collective write?
+    //! Prefer collective write?
+    bool parallel
 );
 
 
@@ -207,7 +210,8 @@ void writeFaceConnectivity
     ensightGeoFile& os,
     const ensightFaces& part,
     const faceUList& faces,
-    bool parallel               //!< Collective write?
+    //! Prefer collective write?
+    bool parallel
 );
 
 
@@ -219,7 +223,8 @@ void writeFaceConnectivityPresorted
     ensightGeoFile& os,
     const ensightFaces& part,
     const faceUList& faces,
-    bool parallel               //!< Collective write?
+    //! Prefer collective write?
+    bool parallel
 );
 
 
@@ -232,10 +237,20 @@ void writeFaceConnectivityPresorted
 template<class Type>
 bool writeField
 (
+    //! Component scratch buffer
+    ensightOutput::floatBufferType& scratch,
+
+    //! Output file (must be valid on master)
     ensightFile& os,
+
+    //! The field content to be written
     const Field<Type>& fld,
+
+    //! The addressing (element-wise) into the field
     const ensightCells& part,
-    bool parallel  //!< Collective write?
+
+    //! Prefer collective write?
+    bool parallel
 );
 
 //- Write a field of faces values as an indirect list,
@@ -243,13 +258,69 @@ bool writeField
 template<class Type>
 bool writeField
 (
+    //! Component scratch buffer
+    ensightOutput::floatBufferType& scratch,
+
+    //! Output file (must be valid on master)
     ensightFile& os,
+
+    //! The field content to be written
     const Field<Type>& fld,
+
+    //! The addressing (element-wise) into the field
     const ensightFaces& part,
-    bool parallel  //!< Collective write?
+
+    //! Prefer collective write?
+    bool parallel
 );
 
 
+//- Write a field of cell values as an indirect list,
+//- using the cell ids from ensightCells
+template<class Type>
+bool writeField
+(
+    //! Output file (must be valid on master)
+    ensightFile& os,
+
+    //! The field content to be written
+    const Field<Type>& fld,
+
+    //! The addressing (element-wise) into the field
+    const ensightCells& part,
+
+    //! Prefer collective write?
+    bool parallel
+)
+{
+    ensightOutput::floatBufferType scratch;
+    return ensightOutput::writeField(scratch, os, fld, part, parallel);
+}
+
+
+//- Write a field of faces values as an indirect list,
+//- using the face ids from ensightFaces
+template<class Type>
+bool writeField
+(
+    //! Output file (must be valid on master)
+    ensightFile& os,
+
+    //! The field content to be written
+    const Field<Type>& fld,
+
+    //! The addressing (element-wise) into the field
+    const ensightFaces& part,
+
+    //! Prefer collective write?
+    bool parallel
+)
+{
+    ensightOutput::floatBufferType scratch;
+    return ensightOutput::writeField(scratch, os, fld, part, parallel);
+}
+
+
 /*---------------------------------------------------------------------------*\
                         Namespace ensightOutput::Detail
 \*---------------------------------------------------------------------------*/
@@ -302,48 +373,109 @@ void writeLabelListList
 );
 
 
-//- Copy specified field component into a scalar buffer
-//- works for various lists types. Must be adequately sized before calling
+//- Copy specified field component into a scalar buffer.
+//- Works for various lists types. Must be adequately sized before calling
 template<template<typename> class FieldContainer, class Type>
 void copyComponent
 (
-    List<scalar>& cmptBuffer,
+    //! Input field data
     const FieldContainer<Type>& input,
-    const direction cmpt
+
+    //! Component to be extracted
+    const direction cmpt,
+
+    //! [out] Component scratch buffer
+    UList<float>& cmptBuffer
 );
 
 
-//- Write field content (component-wise)
-template<template<typename> class FieldContainer, class Type>
-void writeFieldContent
-(
-    ensightFile& os,
-    const FieldContainer<Type>& fld,
-    bool parallel  //!< Collective write?
-);
-
-
-//- Write coordinates (component-wise) for the given part
+//- Write coordinates (component-wise) for the given part.
+//
+//  Has internal check for (nPoints != 0)
 template<template<typename> class FieldContainer>
 bool writeCoordinates
 (
+    //! Output file (must be valid on master)
     ensightGeoFile& os,
+
+    //! The ensight part id
     const label partId,
+
+    //! The ensight part description
     const word& partName,
+
+    //! The total number of points
     const label nPoints,
+
+    //! The point field to be written
     const FieldContainer<Foam::point>& fld,
-    bool parallel  //!< Collective write?
+
+    //! Prefer collective write?
+    bool parallel
 );
 
 
-//- Write field content (component-wise) for the given ensight element type
+//- Write field content (component-wise) for the given ensight element type.
 template<template<typename> class FieldContainer, class Type>
-bool writeFieldComponents
+void writeFieldComponents
 (
+    //! Component scratch buffer
+    ensightOutput::floatBufferType& scratch,
+
+    //! Output file (must be valid on master)
     ensightFile& os,
+
+    //! The ensight element type (ignored if nullptr)
     const char* key,
+
+    //! The field content to be written for this element type
     const FieldContainer<Type>& fld,
-    bool parallel  //!< Collective write?
+
+    //! Prefer collective write?
+    bool parallel
+);
+
+//- Write field content (component-wise) for the given ensight element type.
+template<template<typename> class FieldContainer, class Type>
+void writeFieldComponents
+(
+    //! Output file (must be valid on master)
+    ensightFile& os,
+
+    //! The ensight element type (can be nullptr)
+    const char* key,
+
+    //! The field content to be written for this element type
+    const FieldContainer<Type>& fld,
+
+    //!< Prefer collective write?
+    bool parallel
+)
+{
+    ensightOutput::floatBufferType scratch;
+    Detail::writeFieldComponents(scratch, os, key, fld, parallel);
+}
+
+
+//- Write a sub-field of faces values as an indirect list,
+//- using the sub-list sizing information from ensightFaces
+template<class Type>
+bool writeFaceSubField
+(
+    //! Component scratch buffer
+    ensightOutput::floatBufferType& scratch,
+
+    //! Output file (must be valid on master)
+    ensightFile& os,
+
+    //! The field content to be written
+    const Field<Type>& fld,
+
+    //! The addressing (element-wise) into the field
+    const ensightFaces& part,
+
+    //! Prefer collective write?
+    bool parallel
 );
 
 
@@ -352,11 +484,22 @@ bool writeFieldComponents
 template<class Type>
 bool writeFaceSubField
 (
+    //! Output file (must be valid on master)
     ensightFile& os,
+
+    //! The field content to be written
     const Field<Type>& fld,
+
+    //! The addressing (element-wise) into the field
     const ensightFaces& part,
-    bool parallel  //!< Collective write?
-);
+
+    //! Prefer collective write?
+    bool parallel
+)
+{
+    ensightOutput::floatBufferType scratch;
+    return Detail::writeFaceSubField(scratch, os, fld, part, parallel);
+}
 
 
 //- Write a field of faces values as an indirect list,
@@ -364,12 +507,44 @@ bool writeFaceSubField
 template<class Type>
 bool writeFaceLocalField
 (
+    //! Component scratch buffer
+    ensightOutput::floatBufferType& scratch,
+
+    //! Output file (must be valid on master)
     ensightFile& os,
+
+    //! The field content to be written
     const Field<Type>& fld,
+
+    //! The addressing (element-wise) into the field
     const ensightFaces& part,
-    bool parallel  //!< Collective write?
+
+    //! Prefer collective write?
+    bool parallel
 );
 
+//- Write a field of faces values as an indirect list,
+//- using the face order from ensightFaces
+template<class Type>
+bool writeFaceLocalField
+(
+    //! Output file (must be valid on master)
+    ensightFile& os,
+
+    //! The field content to be written
+    const Field<Type>& fld,
+
+    //! The addressing (element-wise) into the field
+    const ensightFaces& part,
+
+    //! Prefer collective write?
+    bool parallel
+)
+{
+    ensightOutput::floatBufferType scratch;
+    return Detail::writeFaceLocalField(scratch, os, fld, part, parallel);
+}
+
 
 } // End namespace Detail
 
diff --git a/src/fileFormats/ensight/output/ensightOutputFwd.H b/src/fileFormats/ensight/output/ensightOutputFwd.H
new file mode 100644
index 0000000000..ac2e1c6432
--- /dev/null
+++ b/src/fileFormats/ensight/output/ensightOutputFwd.H
@@ -0,0 +1,78 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | www.openfoam.com
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+    Copyright (C) 2022 OpenCFD Ltd.
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Namespace
+    Foam::ensightOutput
+
+Description
+    A collection of functions for writing ensight file content.
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef Foam_ensightOutputFwd_H
+#define Foam_ensightOutputFwd_H
+
+#include "DynamicList.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+// Forward Declarations
+class ensightFile;
+class ensightGeoFile;
+
+
+/*---------------------------------------------------------------------------*\
+                        Namespace ensightOutput
+\*---------------------------------------------------------------------------*/
+
+namespace ensightOutput
+{
+
+//- The list type used for component-wise buffering.
+//  Always has value_type = \c float (what ensight uses internally)
+typedef DynamicList<float> floatBufferType;
+
+//- Static debugging option
+extern int debug;
+
+//- Upper limit on number of items for bundled off-processor field transfers.
+//- The component-wise transfer uses float (4 bytes).
+//  Eg, 5M for 50 ranks of 100k cells each
+extern int maxChunk_;
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace ensightOutput
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //
diff --git a/src/fileFormats/ensight/output/ensightOutputTemplates.C b/src/fileFormats/ensight/output/ensightOutputTemplates.C
index 13b15daaeb..b6470dd9b5 100644
--- a/src/fileFormats/ensight/output/ensightOutputTemplates.C
+++ b/src/fileFormats/ensight/output/ensightOutputTemplates.C
@@ -55,9 +55,9 @@ void Foam::ensightOutput::Detail::writeLabelListList
 template<template<typename> class FieldContainer, class Type>
 void Foam::ensightOutput::Detail::copyComponent
 (
-    List<scalar>& cmptBuffer,
     const FieldContainer<Type>& input,
-    const direction cmpt
+    const direction cmpt,
+    UList<float>& cmptBuffer
 )
 {
     if (cmptBuffer.size() < input.size())
@@ -70,78 +70,178 @@ void Foam::ensightOutput::Detail::copyComponent
 
     auto iter = cmptBuffer.begin();
 
-    for (const Type& val : input)
+    if (std::is_same<float, typename pTraits<Type>::cmptType>::value)
     {
-        *iter = component(val, cmpt);
-        ++iter;
+        // Direct copy
+        for (const Type& val : input)
+        {
+            *iter = component(val, cmpt);
+            ++iter;
+        }
+    }
+    else
+    {
+        // Copy with narrowing
+        for (const Type& val : input)
+        {
+            *iter = narrowFloat(component(val, cmpt));
+            ++iter;
+        }
     }
 }
 
 
 template<template<typename> class FieldContainer, class Type>
-void Foam::ensightOutput::Detail::writeFieldContent
+void Foam::ensightOutput::Detail::writeFieldComponents
 (
+    ensightOutput::floatBufferType& scratch,
     ensightFile& os,
+    const char* key,
     const FieldContainer<Type>& fld,
     bool parallel
 )
 {
-    // already checked prior to calling, but extra safety
     parallel = parallel && Pstream::parRun();
 
+    const label localSize = fld.size();
+
     // Gather sizes (offsets irrelevant)
     const globalIndex procAddr
     (
         parallel
-      ? globalIndex(globalIndex::gatherOnly{}, fld.size())
-      : globalIndex(globalIndex::gatherNone{}, fld.size())
+      ? globalIndex(globalIndex::gatherOnly{}, localSize)
+      : globalIndex(globalIndex::gatherNone{}, localSize)
     );
 
+    if (Pstream::master() && key)
+    {
+        os.writeKeyword(key);
+    }
 
     if (Pstream::master())
     {
-        DynamicList<scalar> cmptBuffer(procAddr.maxSize());
+        // Buffer size needed for an individual rank
+        const label minSize(max(localSize, procAddr.maxSize()));
+
+        // Buffer size needed for all nonLocal ranks
+        const label nonLocalSize(procAddr.totalSize() - localSize);
+
+        // Maximum off-processor transfer size
+        const label maxTransfer =
+        (
+            (ensightOutput::maxChunk_ > 0)
+          ? min(static_cast<label>(ensightOutput::maxChunk_), nonLocalSize)
+          : static_cast<label>(0)
+        );
+
+        // Allocate at least enough to process a single rank, but potentially
+        // receive multiple ranks at a time before writing
+
+        scratch.resize_nocopy(max(minSize, maxTransfer));
+
+        if (Pstream::master() && debug > 1)
+        {
+            Info<< "ensight";
+            if (key)
+            {
+                Info<< " (" << key << ')';
+            }
+
+            Info<< " total-size:" << procAddr.totalSize()
+                << " buf-size:" << scratch.size() << "/" << scratch.capacity()
+                << " any-proc:" << minSize
+                << " off-proc:" << nonLocalSize << endl;
+
+            Info<< "proc-sends: (";
+
+            label nPending = localSize;
+
+            Info<< (localSize ? '0' : '_');
+
+            // Receive others, writing as needed
+            for (const label proci : procAddr.subProcs())
+            {
+                const label procSize = procAddr.localSize(proci);
+
+                if (procSize)
+                {
+                    if (nPending + procSize > scratch.size())
+                    {
+                        // Flush buffer
+                        nPending = 0;
+                        Info<< ") (";
+                    }
+                    else
+                    {
+                        Info<< ' ';
+                    }
+
+                    Info<< proci;
+                    nPending += procSize;
+                }
+            }
+
+            Info<< ')' << endl;
+        }
 
         for (direction d=0; d < pTraits<Type>::nComponents; ++d)
         {
             const direction cmpt = ensightPTraits<Type>::componentOrder[d];
 
-            // Write master data
-            cmptBuffer.resize_nocopy(procAddr.localSize(0));
-            copyComponent(cmptBuffer, fld, cmpt);
-            os.writeList(cmptBuffer);
+            // Master
+            copyComponent(fld, cmpt, scratch);
+            label nPending = localSize;
 
-            // Receive and write
+            // Receive others, writing as needed
             for (const label proci : procAddr.subProcs())
             {
-                cmptBuffer.resize_nocopy(procAddr.localSize(proci));
-                UIPstream::read
-                (
-                    UPstream::commsTypes::scheduled,
-                    proci,
-                    cmptBuffer.data_bytes(),
-                    cmptBuffer.size_bytes()
-                );
-                os.writeList(cmptBuffer);
+                const label procSize = procAddr.localSize(proci);
+
+                if (procSize)
+                {
+                    if (nPending + procSize > scratch.size())
+                    {
+                        // Flush buffer
+                        os.writeList(SubList<float>(scratch, nPending));
+                        nPending = 0;
+                    }
+
+                    SubList<float> slot(scratch, procSize, nPending);
+                    nPending += procSize;
+
+                    UIPstream::read
+                    (
+                        UPstream::commsTypes::scheduled,
+                        proci,
+                        slot.data_bytes(),
+                        slot.size_bytes()
+                    );
+                }
+            }
+
+            if (nPending)
+            {
+                // Flush buffer
+                os.writeList(SubList<float>(scratch, nPending));
             }
         }
     }
-    else if (parallel)
+    else if (parallel && localSize)
     {
-        // Send
-        List<scalar> cmptBuffer(fld.size());
+        scratch.resize_nocopy(localSize);
 
         for (direction d=0; d < pTraits<Type>::nComponents; ++d)
         {
             const direction cmpt = ensightPTraits<Type>::componentOrder[d];
 
-            copyComponent(cmptBuffer, fld, cmpt);
+            copyComponent(fld, cmpt, scratch);
+
             UOPstream::write
             (
                 UPstream::commsTypes::scheduled,
                 UPstream::masterNo(),
-                cmptBuffer.cdata_bytes(),
-                cmptBuffer.size_bytes()
+                scratch.cdata_bytes(),
+                scratch.size_bytes()
             );
         }
     }
@@ -159,45 +259,31 @@ bool Foam::ensightOutput::Detail::writeCoordinates
     bool parallel
 )
 {
-    parallel = parallel && Pstream::parRun();
-
     if (Pstream::master())
     {
         os.beginPart(partId, partName);
         os.beginCoordinates(nPoints);
     }
 
-    ensightOutput::Detail::writeFieldContent(os, fld, parallel);
-
-    return true;
-}
-
-
-template<template<typename> class FieldContainer, class Type>
-bool Foam::ensightOutput::Detail::writeFieldComponents
-(
-    ensightFile& os,
-    const char* key,
-    const FieldContainer<Type>& fld,
-    bool parallel
-)
-{
-    parallel = parallel && Pstream::parRun();
-
-    // Preliminary checks
+    bool ok = (Pstream::master() && (nPoints > 0));
+    if (parallel)
     {
-        // No field
-        if (parallel ? returnReduceAnd(fld.empty()) : fld.empty()) return false;
+        Pstream::broadcast(ok);
     }
 
-
-    if (Pstream::master())
+    if (ok)
     {
-        os.writeKeyword(key);
+        ensightOutput::floatBufferType scratch;
+        ensightOutput::Detail::writeFieldComponents
+        (
+            scratch,
+            os,
+            nullptr,  // (no element type)
+            fld,
+            parallel
+        );
     }
 
-    ensightOutput::Detail::writeFieldContent(os, fld, parallel);
-
     return true;
 }
 
@@ -205,6 +291,7 @@ bool Foam::ensightOutput::Detail::writeFieldComponents
 template<class Type>
 bool Foam::ensightOutput::Detail::writeFaceSubField
 (
+    ensightOutput::floatBufferType& scratch,
     ensightFile& os,
     const Field<Type>& fld,
     const ensightFaces& part,
@@ -213,13 +300,17 @@ bool Foam::ensightOutput::Detail::writeFaceSubField
 {
     parallel = parallel && Pstream::parRun();
 
-    // Preliminary checks: total() contains pre-reduced information
-    {
-        // No geometry
-        if (parallel ? !part.total() : !part.size()) return false;
+    // Need geometry and field. part.total() is already reduced
+    const bool good =
+    (
+        parallel
+      ? (part.total() && returnReduceOr(fld.size()))
+      : (part.size() && fld.size())
+    );
 
-        // No field
-        if (parallel ? returnReduceAnd(fld.empty()) : fld.empty()) return false;
+    if (!good)
+    {
+        return false;
     }
 
 
@@ -232,13 +323,18 @@ bool Foam::ensightOutput::Detail::writeFaceSubField
     {
         const auto etype = ensightFaces::elemType(typei);
 
-        ensightOutput::Detail::writeFieldComponents
-        (
-            os,
-            ensightFaces::key(etype),
-            SubField<Type>(fld, part.range(etype)),
-            parallel
-        );
+        // Write elements of this type
+        if (parallel ? part.total(etype) : part.size(etype))
+        {
+            ensightOutput::Detail::writeFieldComponents
+            (
+                scratch,
+                os,
+                ensightFaces::key(etype),
+                SubField<Type>(fld, part.range(etype)),
+                parallel
+            );
+        }
     }
 
     return true;
@@ -248,6 +344,7 @@ bool Foam::ensightOutput::Detail::writeFaceSubField
 template<class Type>
 bool Foam::ensightOutput::Detail::writeFaceLocalField
 (
+    ensightOutput::floatBufferType& scratch,
     ensightFile& os,
     const Field<Type>& fld,
     const ensightFaces& part,
@@ -256,15 +353,20 @@ bool Foam::ensightOutput::Detail::writeFaceLocalField
 {
     parallel = parallel && Pstream::parRun();
 
-    // Preliminary checks: total() contains pre-reduced information
-    {
-        // No geometry
-        if (parallel ? !part.total() : !part.size()) return false;
+    // Need geometry and field. part.total() is already reduced
+    const bool good =
+    (
+        parallel
+      ? (part.total() && returnReduceOr(fld.size()))
+      : (part.size() && fld.size())
+    );
 
-        // No field
-        if (parallel ? returnReduceAnd(fld.empty()) : fld.empty()) return false;
+    if (!good)
+    {
+        return false;
     }
 
+
     bool validAddressing = (part.size() == part.faceOrder().size());
 
     if (parallel)
@@ -289,13 +391,18 @@ bool Foam::ensightOutput::Detail::writeFaceLocalField
     {
         const auto etype = ensightFaces::elemType(typei);
 
-        ensightOutput::Detail::writeFieldComponents
-        (
-            os,
-            ensightFaces::key(etype),
-            UIndirectList<Type>(fld, part.faceOrder(etype)),
-            parallel
-        );
+        // Write elements of this type
+        if (parallel ? part.total(etype) : part.size(etype))
+        {
+            ensightOutput::Detail::writeFieldComponents
+            (
+                scratch,
+                os,
+                ensightFaces::key(etype),
+                UIndirectList<Type>(fld, part.faceOrder(etype)),
+                parallel
+            );
+        }
     }
 
     return true;
@@ -307,6 +414,7 @@ bool Foam::ensightOutput::Detail::writeFaceLocalField
 template<class Type>
 bool Foam::ensightOutput::writeField
 (
+    ensightOutput::floatBufferType& scratch,
     ensightFile& os,
     const Field<Type>& fld,
     const ensightCells& part,
@@ -315,13 +423,17 @@ bool Foam::ensightOutput::writeField
 {
     parallel = parallel && Pstream::parRun();
 
-    // Preliminary checks: total() contains pre-reduced information
-    {
-        // No geometry
-        if (parallel ? !part.total() : !part.size()) return false;
+    // Need geometry and field. part.total() is already reduced
+    const bool good =
+    (
+        parallel
+      ? (part.total() && returnReduceOr(fld.size()))
+      : (part.size() && fld.size())
+    );
 
-        // No field
-        if (parallel ? returnReduceAnd(fld.empty()) : fld.empty()) return false;
+    if (!good)
+    {
+        return false;
     }
 
 
@@ -334,13 +446,18 @@ bool Foam::ensightOutput::writeField
     {
         const auto etype = ensightCells::elemType(typei);
 
-        ensightOutput::Detail::writeFieldComponents
-        (
-            os,
-            ensightCells::key(etype),
-            UIndirectList<Type>(fld, part.cellIds(etype)),
-            parallel
-        );
+        // Write elements of this type
+        if (parallel ? part.total(etype) : part.size(etype))
+        {
+            ensightOutput::Detail::writeFieldComponents
+            (
+                scratch,
+                os,
+                ensightCells::key(etype),
+                UIndirectList<Type>(fld, part.cellIds(etype)),
+                parallel
+            );
+        }
     }
 
     return true;
@@ -350,6 +467,7 @@ bool Foam::ensightOutput::writeField
 template<class Type>
 bool Foam::ensightOutput::writeField
 (
+    ensightOutput::floatBufferType& scratch,
     ensightFile& os,
     const Field<Type>& fld,
     const ensightFaces& part,
@@ -358,13 +476,17 @@ bool Foam::ensightOutput::writeField
 {
     parallel = parallel && Pstream::parRun();
 
-    // Preliminary checks: total() contains pre-reduced information
-    {
-        // No geometry
-        if (parallel ? !part.total() : !part.size()) return false;
+    // Need geometry and field. part.total() is already reduced
+    const bool good =
+    (
+        parallel
+      ? (part.total() && returnReduceOr(fld.size()))
+      : (part.size() && fld.size())
+    );
 
-        // No field
-        if (parallel ? returnReduceAnd(fld.empty()) : fld.empty()) return false;
+    if (!good)
+    {
+        return false;
     }
 
 
@@ -377,13 +499,18 @@ bool Foam::ensightOutput::writeField
     {
         const auto etype = ensightFaces::elemType(typei);
 
-        ensightOutput::Detail::writeFieldComponents
-        (
-            os,
-            ensightFaces::key(etype),
-            UIndirectList<Type>(fld, part.faceIds(etype)),
-            parallel
-        );
+        // Write elements of this type
+        if (parallel ? part.total(etype) : part.size(etype))
+        {
+            ensightOutput::Detail::writeFieldComponents
+            (
+                scratch,
+                os,
+                ensightFaces::key(etype),
+                UIndirectList<Type>(fld, part.faceIds(etype)),
+                parallel
+            );
+        }
     }
 
     return true;
diff --git a/src/fileFormats/ensight/part/cells/ensightCells.C b/src/fileFormats/ensight/part/cells/ensightCells.C
index a5e26b29c7..398ff131c3 100644
--- a/src/fileFormats/ensight/part/cells/ensightCells.C
+++ b/src/fileFormats/ensight/part/cells/ensightCells.C
@@ -99,7 +99,7 @@ Foam::FixedList<Foam::label, 5> Foam::ensightCells::sizes() const
 {
     FixedList<label, 5> count;
 
-    forAll(count, typei)
+    for (int typei = 0; typei < nTypes; ++typei)
     {
         count[typei] = size(elemType(typei));
     }
@@ -108,14 +108,14 @@ Foam::FixedList<Foam::label, 5> Foam::ensightCells::sizes() const
 }
 
 
-Foam::label Foam::ensightCells::total() const
+Foam::label Foam::ensightCells::totalSize() const noexcept
 {
-    label nTotal = 0;
-    forAll(sizes_, typei)
+    label count = 0;
+    for (label n : sizes_)
     {
-        nTotal += sizes_[typei];
+        count += n;
     }
-    return nTotal;
+    return count;
 }
 
 
@@ -137,11 +137,10 @@ void Foam::ensightCells::clearOut()
 
 void Foam::ensightCells::reduce()
 {
-    forAll(sizes_, typei)
+    for (int typei = 0; typei < nTypes; ++typei)
     {
         sizes_[typei] = size(elemType(typei));
     }
-    // Can reduce FixedList with sumOp<label> in a single operation
     Foam::reduce(sizes_, sumOp<label>());
 }
 
diff --git a/src/fileFormats/ensight/part/cells/ensightCells.H b/src/fileFormats/ensight/part/cells/ensightCells.H
index f2f7edce17..928399f45e 100644
--- a/src/fileFormats/ensight/part/cells/ensightCells.H
+++ b/src/fileFormats/ensight/part/cells/ensightCells.H
@@ -82,7 +82,7 @@ public:
     // Static Functions
 
         //- The ensight element name for the specified 'Cell' type
-        inline static const char* key(const elemType etype);
+        inline static const char* key(const elemType etype) noexcept;
 
 
 private:
@@ -183,7 +183,10 @@ public:
 
         //- The global size of all element types.
         //  This value is only meaningful after a reduce operation.
-        label total() const;
+        label totalSize() const noexcept;
+
+        //- Same as totalSize()
+        label total() const noexcept { return totalSize(); }
 
         //- The global size of the specified element type.
         //  This value is only meaningful after a reduce operation.
diff --git a/src/fileFormats/ensight/part/cells/ensightCellsI.H b/src/fileFormats/ensight/part/cells/ensightCellsI.H
index 52515d0c14..956e2606b9 100644
--- a/src/fileFormats/ensight/part/cells/ensightCellsI.H
+++ b/src/fileFormats/ensight/part/cells/ensightCellsI.H
@@ -46,7 +46,7 @@ inline bool Foam::ensightCells::manifold() const noexcept
 }
 
 
-inline const char* Foam::ensightCells::key(const elemType etype)
+inline const char* Foam::ensightCells::key(const elemType etype) noexcept
 {
     return elemNames[etype];
 }
diff --git a/src/fileFormats/ensight/part/faces/ensightFaces.C b/src/fileFormats/ensight/part/faces/ensightFaces.C
index 22095fdeaf..404a4e3f34 100644
--- a/src/fileFormats/ensight/part/faces/ensightFaces.C
+++ b/src/fileFormats/ensight/part/faces/ensightFaces.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -124,7 +124,7 @@ Foam::FixedList<Foam::label, 3> Foam::ensightFaces::sizes() const
 {
     FixedList<label, 3> count;
 
-    forAll(count, typei)
+    for (int typei = 0; typei < nTypes; ++typei)
     {
         count[typei] = size(elemType(typei));
     }
@@ -133,14 +133,14 @@ Foam::FixedList<Foam::label, 3> Foam::ensightFaces::sizes() const
 }
 
 
-Foam::label Foam::ensightFaces::total() const
+Foam::label Foam::ensightFaces::totalSize() const noexcept
 {
-    label nTotal = 0;
-    forAll(sizes_, typei)
+    label count = 0;
+    for (label n : sizes_)
     {
-        nTotal += sizes_[typei];
+        count += n;
     }
-    return nTotal;
+    return count;
 }
 
 
@@ -163,11 +163,10 @@ void Foam::ensightFaces::clearOut()
 
 void Foam::ensightFaces::reduce()
 {
-    forAll(sizes_, typei)
+    for (int typei = 0; typei < nTypes; ++typei)
     {
         sizes_[typei] = size(elemType(typei));
     }
-    // Can reduce FixedList with sumOp<label> in a single operation
     Foam::reduce(sizes_, sumOp<label>());
 }
 
diff --git a/src/fileFormats/ensight/part/faces/ensightFaces.H b/src/fileFormats/ensight/part/faces/ensightFaces.H
index 275fc3b1dd..8b4cff2819 100644
--- a/src/fileFormats/ensight/part/faces/ensightFaces.H
+++ b/src/fileFormats/ensight/part/faces/ensightFaces.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -97,7 +97,7 @@ public:
     // Static Functions
 
         //- The ensight element name for the specified 'Face' type
-        static inline const char* key(const elemType etype);
+        static inline const char* key(const elemType etype) noexcept;
 
 
 private:
@@ -162,7 +162,10 @@ public:
 
         //- The global size of all element types.
         //  This value is only meaningful after a reduce operation.
-        label total() const;
+        label totalSize() const noexcept;
+
+        //- Same as totalSize
+        label total() const noexcept { return totalSize(); }
 
         //- The global size of the specified element type.
         //  This value is only meaningful after a reduce operation.
diff --git a/src/fileFormats/ensight/part/faces/ensightFacesI.H b/src/fileFormats/ensight/part/faces/ensightFacesI.H
index 1560d87fb6..a188260172 100644
--- a/src/fileFormats/ensight/part/faces/ensightFacesI.H
+++ b/src/fileFormats/ensight/part/faces/ensightFacesI.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -46,7 +46,7 @@ Foam::ensightFaces::add(const elemType etype, label id, bool flip)
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-inline const char* Foam::ensightFaces::key(const elemType etype)
+inline const char* Foam::ensightFaces::key(const elemType etype) noexcept
 {
     return elemNames[etype];
 }
diff --git a/src/fileFormats/ensight/type/ensightPTraits.C b/src/fileFormats/ensight/type/ensightPTraits.C
index 9eaf9d30f6..aca6dfb4be 100644
--- a/src/fileFormats/ensight/type/ensightPTraits.C
+++ b/src/fileFormats/ensight/type/ensightPTraits.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2013-2015 OpenFOAM Foundation
-    Copyright (C) 2019 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -41,11 +41,20 @@ Foam::ensightPTraits<Foam::label>::componentOrder[] = {0};
 
 template<>
 const char* const
-Foam::ensightPTraits<Foam::scalar>::typeName = "scalar";
+Foam::ensightPTraits<float>::typeName = "scalar";
 
 template<>
 const Foam::direction
-Foam::ensightPTraits<Foam::scalar>::componentOrder[] = {0};
+Foam::ensightPTraits<float>::componentOrder[] = {0};
+
+
+template<>
+const char* const
+Foam::ensightPTraits<double>::typeName = "scalar";
+
+template<>
+const Foam::direction
+Foam::ensightPTraits<double>::componentOrder[] = {0};
 
 
 template<>
diff --git a/src/fileFormats/ensight/type/ensightPTraits.H b/src/fileFormats/ensight/type/ensightPTraits.H
index be7e40b48a..c2244655b4 100644
--- a/src/fileFormats/ensight/type/ensightPTraits.H
+++ b/src/fileFormats/ensight/type/ensightPTraits.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2013-2015 OpenFOAM Foundation
-    Copyright (C) 2019-2021 OpenCFD Ltd.
+    Copyright (C) 2019-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -47,7 +47,7 @@ namespace Foam
 {
 
 /*---------------------------------------------------------------------------*\
-                         Class ensightPTraits Declaration
+                       Class ensightPTraits Declaration
 \*---------------------------------------------------------------------------*/
 
 template<class Type>
@@ -69,8 +69,11 @@ struct ensightPTraits
 template<> const char* const ensightPTraits<label>::typeName;
 template<> const direction ensightPTraits<label>::componentOrder[];
 
-template<> const char* const ensightPTraits<scalar>::typeName;
-template<> const direction ensightPTraits<scalar>::componentOrder[];
+template<> const char* const ensightPTraits<float>::typeName;
+template<> const direction ensightPTraits<float>::componentOrder[];
+
+template<> const char* const ensightPTraits<double>::typeName;
+template<> const direction ensightPTraits<double>::componentOrder[];
 
 template<> const char* const ensightPTraits<vector>::typeName;
 template<> const direction ensightPTraits<vector>::componentOrder[];
diff --git a/src/fileFormats/vtk/output/foamVtkOutput.C b/src/fileFormats/vtk/output/foamVtkOutput.C
index e4f33eb710..338f7b555f 100644
--- a/src/fileFormats/vtk/output/foamVtkOutput.C
+++ b/src/fileFormats/vtk/output/foamVtkOutput.C
@@ -130,7 +130,7 @@ void Foam::vtk::writeListParallel
 )
 {
     // Gather sizes (offsets irrelevant)
-    const globalIndex procAddr(values.size(), globalIndex::gatherOnly{});
+    const globalIndex procAddr(globalIndex::gatherOnly{}, values.size());
 
     if (Pstream::master())
     {
@@ -146,33 +146,40 @@ void Foam::vtk::writeListParallel
 
         for (const label proci : procAddr.subProcs())
         {
-            recvData.resize_nocopy(procAddr.localSize(proci));
-            UIPstream::read
-            (
-                UPstream::commsTypes::scheduled,
-                proci,
-                recvData.data_bytes(),
-                recvData.size_bytes()
-            );
+            const label procSize = procAddr.localSize(proci);
 
-            // With value offset
-            const label offsetId = procOffset.localStart(proci);
-            for (const label val : recvData)
+            if (procSize)
             {
-                vtk::write(fmt, val + offsetId);
+                recvData.resize_nocopy(procSize);
+                UIPstream::read
+                (
+                    UPstream::commsTypes::scheduled,
+                    proci,
+                    recvData.data_bytes(),
+                    recvData.size_bytes()
+                );
+
+                // With value offset
+                const label offsetId = procOffset.localStart(proci);
+                for (const label val : recvData)
+                {
+                    vtk::write(fmt, val + offsetId);
+                }
             }
         }
     }
     else
     {
-        // Send
-        UOPstream::write
-        (
-            UPstream::commsTypes::scheduled,
-            UPstream::masterNo(),
-            values.cdata_bytes(),
-            values.size_bytes()
-        );
+        if (values.size())
+        {
+            UOPstream::write
+            (
+                UPstream::commsTypes::scheduled,
+                UPstream::masterNo(),
+                values.cdata_bytes(),
+                values.size_bytes()
+            );
+        }
     }
 }
 
diff --git a/src/fileFormats/vtk/output/foamVtkOutputTemplates.C b/src/fileFormats/vtk/output/foamVtkOutputTemplates.C
index ef8c9d11bc..552cf654bd 100644
--- a/src/fileFormats/vtk/output/foamVtkOutputTemplates.C
+++ b/src/fileFormats/vtk/output/foamVtkOutputTemplates.C
@@ -171,7 +171,7 @@ void Foam::vtk::writeListParallel
 
 
     // Gather sizes (offsets irrelevant)
-    const globalIndex procAddr(values.size(), globalIndex::gatherOnly{});
+    const globalIndex procAddr(globalIndex::gatherOnly{}, values.size());
 
 
     if (Pstream::master())
@@ -184,27 +184,34 @@ void Foam::vtk::writeListParallel
 
         for (const label proci : procAddr.subProcs())
         {
-            recvData.resize_nocopy(procAddr.localSize(proci));
-            UIPstream::read
-            (
-                UPstream::commsTypes::scheduled,
-                proci,
-                recvData.data_bytes(),
-                recvData.size_bytes()
-            );
-            vtk::writeList(fmt, recvData);
+            const label procSize = procAddr.localSize(proci);
+
+            if (procSize)
+            {
+                recvData.resize_nocopy(procSize);
+                UIPstream::read
+                (
+                    UPstream::commsTypes::scheduled,
+                    proci,
+                    recvData.data_bytes(),
+                    recvData.size_bytes()
+                );
+                vtk::writeList(fmt, recvData);
+            }
         }
     }
     else
     {
-        // Send
-        UOPstream::write
-        (
-            UPstream::commsTypes::scheduled,
-            UPstream::masterNo(),
-            values.cdata_bytes(),
-            values.size_bytes()
-        );
+        if (values.size())
+        {
+            UOPstream::write
+            (
+                UPstream::commsTypes::scheduled,
+                UPstream::masterNo(),
+                values.cdata_bytes(),
+                values.size_bytes()
+            );
+        }
     }
 }
 
@@ -233,7 +240,7 @@ void Foam::vtk::writeListParallel
     }
 
     // Gather sizes (offsets irrelevant)
-    const globalIndex procAddr(sendData.size(), globalIndex::gatherOnly{});
+    const globalIndex procAddr(globalIndex::gatherOnly{}, sendData.size());
 
 
     if (Pstream::master())
@@ -246,26 +253,34 @@ void Foam::vtk::writeListParallel
 
         for (const label proci : procAddr.subProcs())
         {
-            recvData.resize_nocopy(procAddr.localSize(proci));
-            UIPstream::read
-            (
-                UPstream::commsTypes::scheduled,
-                proci,
-                recvData.data_bytes(),
-                recvData.size_bytes()
-            );
-            vtk::writeList(fmt, recvData);
+            const label procSize = procAddr.localSize(proci);
+
+            if (procSize)
+            {
+                recvData.resize_nocopy(procSize);
+                UIPstream::read
+                (
+                    UPstream::commsTypes::scheduled,
+                    proci,
+                    recvData.data_bytes(),
+                    recvData.size_bytes()
+                );
+                vtk::writeList(fmt, recvData);
+            }
         }
     }
     else
     {
-        UOPstream::write
-        (
-            UPstream::commsTypes::scheduled,
-            UPstream::masterNo(),
-            sendData.cdata_bytes(),
-            sendData.size_bytes()
-        );
+        if (sendData.size())
+        {
+            UOPstream::write
+            (
+                UPstream::commsTypes::scheduled,
+                UPstream::masterNo(),
+                sendData.cdata_bytes(),
+                sendData.size_bytes()
+            );
+        }
     }
 }
 
@@ -294,7 +309,7 @@ void Foam::vtk::writeListParallel
     }
 
     // Gather sizes (offsets irrelevant)
-    const globalIndex procAddr(sendData.size(), globalIndex::gatherOnly{});
+    const globalIndex procAddr(globalIndex::gatherOnly{}, sendData.size());
 
 
     if (Pstream::master())
@@ -307,26 +322,35 @@ void Foam::vtk::writeListParallel
 
         for (const label proci : procAddr.subProcs())
         {
-            recvData.resize_nocopy(procAddr.localSize(proci));
-            UIPstream::read
-            (
-                UPstream::commsTypes::scheduled,
-                proci,
-                recvData.data_bytes(),
-                recvData.size_bytes()
-            );
-            vtk::writeList(fmt, recvData);
+            const label procSize = procAddr.localSize(proci);
+
+            if (procSize)
+            {
+                recvData.resize_nocopy(procSize);
+
+                UIPstream::read
+                (
+                    UPstream::commsTypes::scheduled,
+                    proci,
+                    recvData.data_bytes(),
+                    recvData.size_bytes()
+                );
+                vtk::writeList(fmt, recvData);
+            }
         }
     }
     else
     {
-        UOPstream::write
-        (
-            UPstream::commsTypes::scheduled,
-            UPstream::masterNo(),
-            sendData.cdata_bytes(),
-            sendData.size_bytes()
-        );
+        if (sendData.size())
+        {
+            UOPstream::write
+            (
+                UPstream::commsTypes::scheduled,
+                UPstream::masterNo(),
+                sendData.cdata_bytes(),
+                sendData.size_bytes()
+            );
+        }
     }
 }
 
@@ -349,8 +373,8 @@ void Foam::vtk::writeListsParallel
 
 
     // Gather sizes (offsets irrelevant)
-    const globalIndex procAddr1(values1.size(), globalIndex::gatherOnly{});
-    const globalIndex procAddr2(values2.size(), globalIndex::gatherOnly{});
+    const globalIndex procAddr1(globalIndex::gatherOnly{}, values1.size());
+    const globalIndex procAddr2(globalIndex::gatherOnly{}, values2.size());
 
 
     if (Pstream::master())
@@ -368,45 +392,61 @@ void Foam::vtk::writeListsParallel
         for (const label proci : procAddr1.subProcs())
         {
             // values1
-            recvData.resize_nocopy(procAddr1.localSize(proci));
-            UIPstream::read
-            (
-                UPstream::commsTypes::scheduled,
-                proci,
-                recvData.data_bytes(),
-                recvData.size_bytes()
-            );
-            vtk::writeList(fmt, recvData);
+            label procSize = procAddr1.localSize(proci);
+
+            if (procSize)
+            {
+                recvData.resize_nocopy(procSize);
+                UIPstream::read
+                (
+                    UPstream::commsTypes::scheduled,
+                    proci,
+                    recvData.data_bytes(),
+                    recvData.size_bytes()
+                );
+                vtk::writeList(fmt, recvData);
+            }
 
             // values2
-            recvData.resize_nocopy(procAddr2.localSize(proci));
-            UIPstream::read
-            (
-                UPstream::commsTypes::scheduled,
-                proci,
-                recvData.data_bytes(),
-                recvData.size_bytes()
-            );
-            vtk::writeList(fmt, recvData);
+            procSize = procAddr2.localSize(proci);
+
+            if (procSize)
+            {
+                recvData.resize_nocopy(procSize);
+                UIPstream::read
+                (
+                    UPstream::commsTypes::scheduled,
+                    proci,
+                    recvData.data_bytes(),
+                    recvData.size_bytes()
+                );
+                vtk::writeList(fmt, recvData);
+            }
         }
     }
     else
     {
-        UOPstream::write
-        (
-            UPstream::commsTypes::scheduled,
-            UPstream::masterNo(),
-            values1.cdata_bytes(),
-            values1.size_bytes()
-        );
+        if (values1.size())
+        {
+            UOPstream::write
+            (
+                UPstream::commsTypes::scheduled,
+                UPstream::masterNo(),
+                values1.cdata_bytes(),
+                values1.size_bytes()
+            );
+        }
 
-        UOPstream::write
-        (
-            UPstream::commsTypes::scheduled,
-            UPstream::masterNo(),
-            values2.cdata_bytes(),
-            values2.size_bytes()
-        );
+        if (values2.size())
+        {
+            UOPstream::write
+            (
+                UPstream::commsTypes::scheduled,
+                UPstream::masterNo(),
+                values2.cdata_bytes(),
+                values2.size_bytes()
+            );
+        }
     }
 }
 
@@ -437,8 +477,8 @@ void Foam::vtk::writeListsParallel
 
 
     // Gather sizes (offsets irrelevant)
-    const globalIndex procAddr1(values1.size(), globalIndex::gatherOnly{});
-    const globalIndex procAddr2(sendData2.size(), globalIndex::gatherOnly{});
+    const globalIndex procAddr1(globalIndex::gatherOnly{}, values1.size());
+    const globalIndex procAddr2(globalIndex::gatherOnly{}, sendData2.size());
 
 
     if (Pstream::master())
@@ -457,45 +497,61 @@ void Foam::vtk::writeListsParallel
         for (const label proci : procAddr1.subProcs())
         {
             // values1
-            recvData.resize_nocopy(procAddr1.localSize(proci));
-            UIPstream::read
-            (
-                UPstream::commsTypes::scheduled,
-                proci,
-                recvData.data_bytes(),
-                recvData.size_bytes()
-            );
-            vtk::writeList(fmt, recvData);
+            label procSize = procAddr1.localSize(proci);
+
+            if (procSize)
+            {
+                recvData.resize_nocopy(procSize);
+                UIPstream::read
+                (
+                    UPstream::commsTypes::scheduled,
+                    proci,
+                    recvData.data_bytes(),
+                    recvData.size_bytes()
+                );
+                vtk::writeList(fmt, recvData);
+            }
 
             // values2
-            recvData.resize_nocopy(procAddr2.localSize(proci));
-            UIPstream::read
-            (
-                UPstream::commsTypes::scheduled,
-                proci,
-                recvData.data_bytes(),
-                recvData.size_bytes()
-            );
-            vtk::writeList(fmt, recvData);
+            procSize = procAddr2.localSize(proci);
+
+            if (procSize)
+            {
+                recvData.resize_nocopy(procSize);
+                UIPstream::read
+                (
+                    UPstream::commsTypes::scheduled,
+                    proci,
+                    recvData.data_bytes(),
+                    recvData.size_bytes()
+                );
+                vtk::writeList(fmt, recvData);
+            }
         }
     }
     else
     {
-        UOPstream::write
-        (
-            UPstream::commsTypes::scheduled,
-            UPstream::masterNo(),
-            values1.cdata_bytes(),
-            values1.size_bytes()
-        );
+        if (values1.size())
+        {
+            UOPstream::write
+            (
+                UPstream::commsTypes::scheduled,
+                UPstream::masterNo(),
+                values1.cdata_bytes(),
+                values1.size_bytes()
+            );
+        }
 
-        UOPstream::write
-        (
-            UPstream::commsTypes::scheduled,
-            UPstream::masterNo(),
-            sendData2.cdata_bytes(),
-            sendData2.size_bytes()
-        );
+        if (sendData2.size())
+        {
+            UOPstream::write
+            (
+                UPstream::commsTypes::scheduled,
+                UPstream::masterNo(),
+                sendData2.cdata_bytes(),
+                sendData2.size_bytes()
+            );
+        }
     }
 }
 
diff --git a/src/functionObjects/utilities/ensightWrite/ensightWrite.C b/src/functionObjects/utilities/ensightWrite/ensightWrite.C
index 36a3b53d18..92f6575d89 100644
--- a/src/functionObjects/utilities/ensightWrite/ensightWrite.C
+++ b/src/functionObjects/utilities/ensightWrite/ensightWrite.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2020 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -26,6 +26,7 @@ License
 \*---------------------------------------------------------------------------*/
 
 #include "ensightWrite.H"
+#include "ensightOutput.H"
 #include "Time.H"
 #include "polyMesh.H"
 #include "addToRunTimeSelectionTable.H"
@@ -47,6 +48,9 @@ namespace functionObjects
 }
 }
 
+// Implementation
+#include "ensightWriteImpl.C"
+
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
 Foam::label Foam::functionObjects::ensightWrite::writeAllVolFields
@@ -57,11 +61,26 @@ Foam::label Foam::functionObjects::ensightWrite::writeAllVolFields
 {
     label count = 0;
 
-    count += writeVolFields<scalar>(proxy, acceptField);
-    count += writeVolFields<vector>(proxy, acceptField);
-    count += writeVolFields<sphericalTensor>(proxy, acceptField);
-    count += writeVolFields<symmTensor>(proxy, acceptField);
-    count += writeVolFields<tensor>(proxy, acceptField);
+    ensightOutput::floatBufferType scratch;
+
+    {
+        #undef  doLocalCode
+        #define doLocalCode(PrimitiveType)              \
+            count += writeVolFieldsImpl<PrimitiveType>  \
+            (                                           \
+                scratch,                                \
+                proxy,                                  \
+                acceptField                             \
+            );
+
+        doLocalCode(scalar);
+        doLocalCode(vector);
+        doLocalCode(sphericalTensor);
+        doLocalCode(symmTensor);
+        doLocalCode(tensor);
+
+        #undef doLocalCode
+    }
 
     return count;
 }
@@ -215,6 +234,8 @@ bool Foam::functionObjects::ensightWrite::write()
         ensMesh_().write(os);
     }
 
+    // TBD: handle allow/deny filters
+
     wordHashSet acceptField(mesh_.names<void>(selectFields_));
 
     // Prune restart fields
diff --git a/src/functionObjects/utilities/ensightWrite/ensightWrite.H b/src/functionObjects/utilities/ensightWrite/ensightWrite.H
index 7ad89894f6..9e049823cd 100644
--- a/src/functionObjects/utilities/ensightWrite/ensightWrite.H
+++ b/src/functionObjects/utilities/ensightWrite/ensightWrite.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2020 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -127,16 +127,18 @@ See also
 
 SourceFiles
     ensightWrite.C
-    ensightWriteTemplates.C
+    ensightWriteImpl.C
+    ensightWriteUpdate.C
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef functionObjects_ensightWrite_H
-#define functionObjects_ensightWrite_H
+#ifndef Foam_functionObjects_ensightWrite_H
+#define Foam_functionObjects_ensightWrite_H
 
 #include "fvMeshFunctionObject.H"
 #include "ensightCase.H"
 #include "ensightMesh.H"
+#include "ensightOutputFwd.H"
 
 #include "interpolation.H"
 #include "volFields.H"
@@ -223,6 +225,15 @@ class ensightWrite
 
     // Write
 
+        //- Write selected volume fields.
+        template<class Type>
+        label writeVolFieldsImpl
+        (
+            ensightOutput::floatBufferType& scratch,
+            const fvMeshSubset& proxy,
+            const wordHashSet& acceptField
+        );
+
         //- Write all volume fields
         label writeAllVolFields
         (
@@ -230,15 +241,6 @@ class ensightWrite
             const wordHashSet& acceptField
         );
 
-        //- Write selected volume fields.
-        template<class Type>
-        label writeVolFields
-        (
-            const fvMeshSubset& proxy,
-            const wordHashSet& acceptField
-        );
-
-
         //- No copy construct
         ensightWrite(const ensightWrite&) = delete;
 
@@ -296,12 +298,6 @@ public:
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
-#ifdef NoRepository
-    #include "ensightWriteTemplates.C"
-#endif
-
-// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
-
 #endif
 
 // ************************************************************************* //
diff --git a/src/functionObjects/utilities/ensightWrite/ensightWriteTemplates.C b/src/functionObjects/utilities/ensightWrite/ensightWriteImpl.C
similarity index 92%
rename from src/functionObjects/utilities/ensightWrite/ensightWriteTemplates.C
rename to src/functionObjects/utilities/ensightWrite/ensightWriteImpl.C
index 8156cd0acb..3fb5204b2e 100644
--- a/src/functionObjects/utilities/ensightWrite/ensightWriteTemplates.C
+++ b/src/functionObjects/utilities/ensightWrite/ensightWriteImpl.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2020 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -30,8 +30,9 @@ License
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
 template<class Type>
-Foam::label Foam::functionObjects::ensightWrite::writeVolFields
+Foam::label Foam::functionObjects::ensightWrite::writeVolFieldsImpl
 (
+    ensightOutput::floatBufferType& scratch,
     const fvMeshSubset& proxy,
     const wordHashSet& acceptField
 )
@@ -58,6 +59,7 @@ Foam::label Foam::functionObjects::ensightWrite::writeVolFields
 
         ensightOutput::writeVolField<Type>
         (
+            scratch,
             os.ref(),
             field,
             ensMesh(),
diff --git a/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloud.C b/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloud.C
index 0a2d6f7687..9d46d9bda2 100644
--- a/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloud.C
+++ b/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloud.C
@@ -35,40 +35,41 @@ License
 
 namespace Foam
 {
-    //- Binary output
-    static inline void writeMeasured_binary
-    (
-        ensightFile& os,
-        const UList<point>& points
-    )
+
+//- Binary output
+static inline void writeMeasured_binary
+(
+    ensightFile& os,
+    const UList<floatVector>& points
+)
+{
+    for (const floatVector& p : points)
     {
-        for (const point& p : points)
-        {
-            os.write(p.x());
-            os.write(p.y());
-            os.write(p.z());
-        }
+        os.write(p.x());
+        os.write(p.y());
+        os.write(p.z());
+    }
+}
+
+//- ASCII output. Id + position together
+static inline label writeMeasured_ascii
+(
+    ensightFile& os,
+    label pointId,
+    const UList<floatVector>& points
+)
+{
+    for (const floatVector& p : points)
+    {
+        os.write(++pointId, 8); // 1-index and an unusual width
+        os.write(p.x());
+        os.write(p.y());
+        os.write(p.z());
+        os.newline();
     }
 
-    //- ASCII output. Id + position together
-    static inline label writeMeasured_ascii
-    (
-        ensightFile& os,
-        label pointId,
-        const UList<point>& points
-    )
-    {
-        for (const point& p : points)
-        {
-            os.write(++pointId, 8); // 1-index and an unusual width
-            os.write(p.x());
-            os.write(p.y());
-            os.write(p.z());
-            os.newline();
-        }
-
-        return pointId;
-    }
+    return pointId;
+}
 
 } // End namespace Foam
 
@@ -77,10 +78,10 @@ namespace Foam
 
 bool Foam::ensightOutput::writeCloudPositions
 (
+    ensightFile& os,
     const fvMesh& mesh,
     const word& cloudName,
-    bool exists,
-    autoPtr<ensightFile>& output
+    bool exists
 )
 {
     label nLocalParcels(0);
@@ -97,7 +98,6 @@ bool Foam::ensightOutput::writeCloudPositions
 
     if (Pstream::master())
     {
-        ensightFile& os = output();
         os.beginParticleCoordinates(nTotParcels);
     }
 
@@ -111,10 +111,12 @@ bool Foam::ensightOutput::writeCloudPositions
     const globalIndex procAddr(nLocalParcels, globalIndex::gatherOnly{});
 
 
-    DynamicList<point> positions;
+    DynamicList<floatVector> positions;
     positions.reserve(Pstream::master() ? procAddr.maxSize() : nLocalParcels);
 
-    // Extract positions
+    // Extract positions from parcel.
+    // Store as floatVector, since that is what Ensight will write anyhow
+
     if (parcelsPtr)
     {
         const auto& parcels = *parcelsPtr;
@@ -123,10 +125,26 @@ bool Foam::ensightOutput::writeCloudPositions
 
         auto outIter = positions.begin();
 
-        for (const passiveParticle& p : parcels)
+        if (std::is_same<float, vector::cmptType>::value)
         {
-            *outIter = p.position();
-            ++outIter;
+            for (const passiveParticle& p : parcels)
+            {
+                *outIter = p.position();
+                ++outIter;
+            }
+        }
+        else
+        {
+            for (const passiveParticle& p : parcels)
+            {
+                vector pos(p.position());
+
+                (*outIter).x() = narrowFloat(pos.x());
+                (*outIter).y() = narrowFloat(pos.y());
+                (*outIter).z() = narrowFloat(pos.z());
+
+                ++outIter;
+            }
         }
 
         parcelsPtr.reset(nullptr);
@@ -134,7 +152,6 @@ bool Foam::ensightOutput::writeCloudPositions
 
     if (Pstream::master())
     {
-        ensightFile& os = output();
         const bool isBinaryOutput = (os.format() == IOstreamOption::BINARY);
 
         label parcelId = 0;
@@ -164,35 +181,42 @@ bool Foam::ensightOutput::writeCloudPositions
         // Receive and write
         for (const label proci : procAddr.subProcs())
         {
-            positions.resize_nocopy(procAddr.localSize(proci));
-            UIPstream::read
-            (
-                UPstream::commsTypes::scheduled,
-                proci,
-                positions.data_bytes(),
-                positions.size_bytes()
-            );
+            const label procSize = procAddr.localSize(proci);
 
-            if (isBinaryOutput)
+            if (procSize)
             {
-                writeMeasured_binary(os, positions);
-            }
-            else
-            {
-                parcelId = writeMeasured_ascii(os, parcelId, positions);
+                positions.resize_nocopy(procSize);
+                UIPstream::read
+                (
+                    UPstream::commsTypes::scheduled,
+                    proci,
+                    positions.data_bytes(),
+                    positions.size_bytes()
+                );
+
+                if (isBinaryOutput)
+                {
+                    writeMeasured_binary(os, positions);
+                }
+                else
+                {
+                    parcelId = writeMeasured_ascii(os, parcelId, positions);
+                }
             }
         }
     }
     else
     {
-        // Send
-        UOPstream::write
-        (
-            UPstream::commsTypes::scheduled,
-            UPstream::masterNo(),
-            positions.cdata_bytes(),
-            positions.size_bytes()
-        );
+        if (positions.size())
+        {
+            UOPstream::write
+            (
+                UPstream::commsTypes::scheduled,
+                UPstream::masterNo(),
+                positions.cdata_bytes(),
+                positions.size_bytes()
+            );
+        }
     }
 
     return true;
diff --git a/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloud.H b/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloud.H
index 894a6aa21c..e83fbecec0 100644
--- a/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloud.H
+++ b/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloud.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2021 OpenCFD Ltd.
+    Copyright (C) 2016-2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -35,11 +35,10 @@ SourceFiles
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef ensightOutputCloud_H
-#define ensightOutputCloud_H
+#ifndef Foam_ensightOutputCloud_H
+#define Foam_ensightOutputCloud_H
 
 #include "ensightFile.H"
-#include "autoPtr.H"
 #include "IOField.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
@@ -59,10 +58,17 @@ namespace ensightOutput
 //- Write cloud positions
 bool writeCloudPositions
 (
+    //! Output file (must be valid on master)
+    ensightFile& os,
+
+    //! The associated volume mesh
     const fvMesh& mesh,
+
+    //! The name of the cloud
     const word& cloudName,
-    bool exists,
-    autoPtr<ensightFile>& output
+
+    //! The processor-local existence
+    bool exists
 );
 
 
@@ -70,19 +76,27 @@ bool writeCloudPositions
 template<class Type>
 bool writeCloudField
 (
-    const IOField<Type>& field,
-    ensightFile& os
+    //! Output file (must be valid on master)
+    ensightFile& os,
+
+    //! The cloud field
+    const IOField<Type>& field
 );
 
 
 //- Read cloud field from IOobject (if exists == true) and write,
 //- always returning true.
 template<class Type>
-bool writeCloudField
+bool readWriteCloudField
 (
-    const IOobject& io,
-    bool exists,
-    autoPtr<ensightFile>& output
+    //! Output file (must be valid on master)
+    ensightFile& os,
+
+    //! The field object name/location for reading
+    const IOobject& fieldObject,
+
+    //! Exists anywhere? May still be missing on a local processor
+    bool existsAny
 );
 
 
@@ -98,9 +112,13 @@ namespace Detail
 template<class Type>
 label writeCloudFieldContent
 (
+    //! Output file (must be valid on master)
     ensightFile& os,
+
     const UList<Type>& fld,
-    label count = 0     //!< The current output count
+
+    //! The current output count
+    label count = 0
 );
 
 
diff --git a/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloudTemplates.C b/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloudTemplates.C
index 76e671640b..cc865cc7d3 100644
--- a/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloudTemplates.C
+++ b/src/lagrangian/intermediate/conversion/ensight/ensightOutputCloudTemplates.C
@@ -69,8 +69,8 @@ Foam::label Foam::ensightOutput::Detail::writeCloudFieldContent
 template<class Type>
 bool Foam::ensightOutput::writeCloudField
 (
-    const IOField<Type>& field,
-    ensightFile& os
+    ensightFile& os,
+    const IOField<Type>& field
 )
 {
     if (returnReduceAnd(field.empty()))
@@ -79,7 +79,7 @@ bool Foam::ensightOutput::writeCloudField
     }
 
     // Gather sizes (offsets irrelevant)
-    const globalIndex procAddr(field.size(), globalIndex::gatherOnly{});
+    const globalIndex procAddr(globalIndex::gatherOnly{}, field.size());
 
     if (Pstream::master())
     {
@@ -99,21 +99,27 @@ bool Foam::ensightOutput::writeCloudField
 
         for (const label proci : procAddr.subProcs())
         {
-            recvData.resize_nocopy(procAddr.localSize(proci));
-            UIPstream::read
-            (
-                UPstream::commsTypes::scheduled,
-                proci,
-                recvData.data_bytes(),
-                recvData.size_bytes()
-            );
+            const label procSize = procAddr.localSize(proci);
 
-            count = ensightOutput::Detail::writeCloudFieldContent
-            (
-                os,
-                recvData,
-                count
-            );
+            if (procSize)
+            {
+                recvData.resize_nocopy(procSize);
+
+                UIPstream::read
+                (
+                    UPstream::commsTypes::scheduled,
+                    proci,
+                    recvData.data_bytes(),
+                    recvData.size_bytes()
+                );
+
+                count = ensightOutput::Detail::writeCloudFieldContent
+                (
+                    os,
+                    recvData,
+                    count
+                );
+            }
         }
 
         // Add final newline if required
@@ -124,14 +130,16 @@ bool Foam::ensightOutput::writeCloudField
     }
     else
     {
-        // Send
-        UOPstream::write
-        (
-            UPstream::commsTypes::scheduled,
-            UPstream::masterNo(),
-            field.cdata_bytes(),
-            field.size_bytes()
-        );
+        if (field.size())
+        {
+            UOPstream::write
+            (
+                UPstream::commsTypes::scheduled,
+                UPstream::masterNo(),
+                field.cdata_bytes(),
+                field.size_bytes()
+            );
+        }
     }
 
     return true;
@@ -139,25 +147,25 @@ bool Foam::ensightOutput::writeCloudField
 
 
 template<class Type>
-bool Foam::ensightOutput::writeCloudField
+bool Foam::ensightOutput::readWriteCloudField
 (
-    const IOobject& io,
-    const bool exists,
-    autoPtr<ensightFile>& output
+    ensightFile& os,
+    const IOobject& fieldObject,
+    const bool existsAny
 )
 {
-    if (exists)
+    if (existsAny)
     {
-        // When exists == true, it exists globally,
+        // When exists == true, it exists somewhere globally,
         // but can still be missing on the local processor.
         // Handle this by READ_IF_PRESENT instead.
 
-        IOobject fieldObj(io);
-        fieldObj.readOpt(IOobject::READ_IF_PRESENT);
+        IOobject io(fieldObject);
+        io.readOpt(IOobject::READ_IF_PRESENT);
 
-        IOField<Type> field(fieldObj);
+        IOField<Type> field(io);
 
-        writeCloudField(field, output.ref());
+        writeCloudField(os, field);
     }
 
     return true;
diff --git a/src/meshTools/coordSet/writers/ensight/ensightCoordSetWriter.C b/src/meshTools/coordSet/writers/ensight/ensightCoordSetWriter.C
index 3a2dcf0bec..91b20276d3 100644
--- a/src/meshTools/coordSet/writers/ensight/ensightCoordSetWriter.C
+++ b/src/meshTools/coordSet/writers/ensight/ensightCoordSetWriter.C
@@ -67,14 +67,22 @@ static void writeTrackField
 
     forAll(fieldPtrs, tracki)
     {
-        // Write as point data
+        const Field<Type>& fld = fieldPtrs[tracki];
 
         os.beginPart(tracki);  // Part index (0-based)
+
+        // Skip if empty. This check is probably redundant
+        if (fld.empty())
+        {
+            continue;
+        }
+
+        // Write as coordinates data
         ensightOutput::Detail::writeFieldComponents
         (
             os,
             ensightFile::coordinates,
-            fieldPtrs[tracki],
+            fld,
             false  /* serial only! */
         );
     }