ENH: improvements for vtkWrite function object (issue #926)

- parallel output.

  The output is now postProcessing/<name> for similar reasoning as
  mentioned in #866 - better alignment with other function objects, no
  collision with foamToVTK output.

- align the input parameters with those of vtkCloud so that we can
  specify the ASCII precision and the padding width for the output
  file names as well.

- emit TimeValue field, support file series generation

- support internal or boundary meshes, combining the result into a vtm
  file.

- can restrict conversion based on zone names, enclosing volumes,
  bounding box

tutorials/heatTransfer/chtMultiRegionFoam/multiRegionHeater/system/controlDict

@@ -52,4 +52,9 @@ maxDi           10.0;
 
 adjustTimeStep  yes;
 
+functions
+{
+    #include "vtkWrite"
+}
+
 // ************************************************************************* //

tutorials/heatTransfer/chtMultiRegionFoam/multiRegionHeater/system/vtkWrite

@@ -0,0 +1,62 @@
+// -*- C++ -*-
+// Use the vtkWrite function object
+
+vtkWrite
+{
+    type    vtkWrite;
+    libs    ("libutilityFunctionObjects.so");
+    log     true;
+
+    writeControl    writeTime;
+    writeInterval   1;
+
+    // Fields to output (words or regex)
+    regions (".*");
+
+    internal    true;
+
+    boundary    true;
+
+    single      false;
+
+    interpolate true;
+
+    // Fields to output (words or regex)
+    fields  (".*");
+
+    //- Output format (ascii | binary) - Default=binary
+    // format  binary;
+
+    //- Use legacy output format - Default=false
+    // legacy  false;
+
+    //- Output directory name - Default="postProcessing/<name>"
+    // directory   "VTK";
+
+    //- Write cell ids as field - Default=true
+    writeIds    false;
+}
+
+
+// Solid walls only
+walls
+{
+    type    vtkWrite;
+    libs    ("libutilityFunctionObjects.so");
+    log     true;
+
+    writeControl    writeTime;
+    writeInterval   1;
+
+    internal    false;
+
+    // single      true;
+
+    regions     ( heater "(?i).*solid" );
+    patches     ( "(?i).*solid_to.*" "heater.*(Air|Water)" );
+
+    fields      (T);
+}
+
+
+// ************************************************************************* //

tutorials/incompressible/simpleFoam/windAroundBuildings/system/vtkWrite

@@ -15,15 +15,69 @@ vtkWrite
     //- Use legacy output format - Default=false
     // legacy  false;
 
-    //- Output directory name - Default="VTK"
+    //- Output directory name - Default="postProcessing/<name>"
     // directory       "VTK";
 
     //- Write cell ids as field - Default=true
-    writeIds        false;
+    writeIds    false;
 
     //- Write more frequent than fields
     writeControl    timeStep;
     writeInterval   25;
 }
 
+subset
+{
+    type    vtkWrite;
+    libs    ("libutilityFunctionObjects.so");
+    log     true;
+
+    // boundary    false;
+
+    interpolate true;
+
+    // Fields to output (words or regex)
+    fields      (U p);
+
+    //- Write cell ids as field - Default=true
+    writeIds    false;
+
+    //- Write more frequent than fields
+    writeControl    timeStep;
+    writeInterval   25;
+
+    // Region of interest
+    selection
+    {
+        dome
+        {
+            action  add;
+            source  sphere;
+            origin  (125 100 0);
+            radius  100;
+        }
+        cylinder
+        {
+            action  subtract;
+            source  cylinder;
+            p1      (125 100 0);
+            p2      (125 100 100);
+            radius  20;
+        }
+        outlet
+        {
+            action  add;
+            source  box;
+            box     (300 -100 -100) (330 250 100);
+        }
+        clipping
+        {
+            action  subset;
+            source  box;
+            box     (-1000 -1000 -1000) (1000 1000 50);
+        }
+    }
+}
+
+
 // ************************************************************************* //