BUG: distributedTriSurfaceMesh: handle zero sized local surfaces

src/meshTools/searchableSurface/triSurfaceMesh.C

@@ -433,7 +433,10 @@ Foam::triSurfaceMesh::edgeTree() const
           + nInternalEdges()
         );
 
-        treeBoundBox bb;
+        treeBoundBox bb(vector::zero, vector::zero);
+
+        if (bEdges.size())
+        {
             label nPoints;
             PatchTools::calcBounds
             (
@@ -451,6 +454,7 @@ Foam::triSurfaceMesh::edgeTree() const
             bb = bb.extend(rndGen, 1e-4);
             bb.min() -= point(ROOTVSMALL, ROOTVSMALL, ROOTVSMALL);
             bb.max() += point(ROOTVSMALL, ROOTVSMALL, ROOTVSMALL);
+        }
 
         scalar oldTol = indexedOctree<treeDataEdge>::perturbTol();
         indexedOctree<treeDataEdge>::perturbTol() = tolerance();

src/meshTools/triSurface/triSurfaceSearch/triSurfaceRegionSearch.C

@@ -121,7 +121,10 @@ Foam::triSurfaceRegionSearch::treeByRegion() const
             );
 
             // Calculate bb without constructing local point numbering.
-            treeBoundBox bb;
+            treeBoundBox bb(vector::zero, vector::zero);
+
+            if (indirectRegionPatches_[regionI].size())
+            {
                 label nPoints;
                 PatchTools::calcBounds
                 (
@@ -136,18 +139,22 @@ Foam::triSurfaceRegionSearch::treeByRegion() const
     //                    << "Surface does not have compact point numbering. "
     //                    << "Of " << surface().points().size()
     //                    << " only " << nPoints
-//                    << " are used. This might give problems in some routines."
+    //                    << " are used."
+    //                    << " This might give problems in some routines."
     //                    << endl;
     //            }
 
-            // Random number generator. Bit dodgy since not exactly random ;-)
+                // Random number generator. Bit dodgy since not exactly
+                // random ;-)
                 Random rndGen(65431);
 
-            // Slightly extended bb. Slightly off-centred just so on symmetric
+                // Slightly extended bb. Slightly off-centred just so
-            // geometry there are fewer face/edge aligned items.
+                // on symmetric geometry there are fewer face/edge
+                // aligned items.
                 bb = bb.extend(rndGen, 1e-4);
                 bb.min() -= point(ROOTVSMALL, ROOTVSMALL, ROOTVSMALL);
                 bb.max() += point(ROOTVSMALL, ROOTVSMALL, ROOTVSMALL);
+            }
 
             treeByRegion_.set
             (

src/meshTools/triSurface/triSurfaceSearch/triSurfaceSearch.C

@@ -200,7 +200,10 @@ Foam::triSurfaceSearch::tree() const
     if (treePtr_.empty())
     {
         // Calculate bb without constructing local point numbering.
-        treeBoundBox bb;
+        treeBoundBox bb(vector::zero, vector::zero);
+
+        if (surface().size())
+        {
             label nPoints;
             PatchTools::calcBounds(surface(), bb, nPoints);
 
@@ -208,7 +211,8 @@ Foam::triSurfaceSearch::tree() const
             {
                 WarningIn("triSurfaceSearch::tree() const")
                     << "Surface does not have compact point numbering."
-                << " Of " << surface().points().size() << " only " << nPoints
+                    << " Of " << surface().points().size()
+                    << " only " << nPoints
                     << " are used. This might give problems in some routines."
                     << endl;
             }
@@ -221,6 +225,7 @@ Foam::triSurfaceSearch::tree() const
             bb = bb.extend(rndGen, 1e-4);
             bb.min() -= point(ROOTVSMALL, ROOTVSMALL, ROOTVSMALL);
             bb.max() += point(ROOTVSMALL, ROOTVSMALL, ROOTVSMALL);
+        }
 
         scalar oldTol = indexedOctree<treeDataTriSurface>::perturbTol();
         indexedOctree<treeDataTriSurface>::perturbTol() = tolerance_;

src/parallel/distributed/distributedTriSurfaceMesh/distributedTriSurfaceMesh.C

@@ -2360,10 +2360,28 @@ bool Foam::distributedTriSurfaceMesh::writeObject
     // Make sure dictionary goes to same directory as surface
     const_cast<fileName&>(dict_.instance()) = searchableSurface::instance();
 
+    // Copy of triSurfaceMesh::writeObject except for the sorting of
+    // triangles by region. This is done so we preserve region names,
+    // even if locally we have zero triangles.
+    {
+        fileName fullPath(searchableSurface::objectPath());
+
+        if (!mkDir(fullPath.path()))
+        {
+            return false;
+        }
+
+        // Important: preserve any zero-sized patches
+        triSurface::write(fullPath, true);
+
+        if (!isFile(fullPath))
+        {
+            return false;
+        }
+    }
+
     // Dictionary needs to be written in ascii - binary output not supported.
-    return
+    return dict_.writeObject(IOstream::ASCII, ver, cmp);
-        triSurfaceMesh::writeObject(fmt, ver, cmp)
-     && dict_.writeObject(IOstream::ASCII, ver, cmp);
 }
 
 

src/parallel/distributed/distributedTriSurfaceMesh/distributedTriSurfaceMesh.H

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2013 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -446,6 +446,10 @@ public:
         // regIOobject implementation
 
             //- Write using given format, version and compression
+            //  Do not use the triSurfaceMesh::writeObject since it
+            //  would filter out empty regions. These need to be preserved
+            //  in case we want to make decisions based on the number of
+            //  regions.
             virtual bool writeObject
             (
                 IOstream::streamFormat fmt,