[vtkusers] Quadratic Hexahedra Continued

[Thompson, David C]

James C. Robinson wrote:
>I have checked my file format by recompiling the SampleMFC application
>using the v4.2 libraries. That application reads in the file perfectly
>(although it has not facility to view the different attributes -
>pressures/flowrates - at the mesh nodes) and so I will conclude (for
>the moment) that my file format isn't the issue.

It may be that SampleMFC doesn't use all of the data contained in the
file; for instance, is it possible that the cell links (lookup table
to get cells that use a particular vertex) table contains incorrect
information which is unused by SampleMFC but _is_ used by the
GeometryFilter in your example below? A stack trace of your application
would really help determine the root cause if you can supply one.

>I have therefore looked
>closely at my program to try and figure out why it crashes. The logic of
>how it works is:
>
>Create a file with all the mesh info in it (data.vtk)
>Read in this file as the new view is opened - use a
>vtkUnstructuredGridReader *pMeshReader
>                pMeshReader->SetFileName(strdup("data.vtk"));
>Then use a vtkUnstructuredGrid
>	    pUnstructuredGrid = pMeshReader->GetOutput() ;
>Now filter the grid (mesh) info to create a viewable object
>               pGeomFilter->SetInput(pUnstructuredGrid) ;
>Then use a vtkPolyDataMapper:
>               pMaterialMapper->SetInput(pGeomFilter->GetOutput());
>Finally associate this mapper with an actor:
>               pMeshMaterialActor->SetMapper(pMaterialMapper);
>
>Are we sure that all of these objects have been sufficiently debugged
>and that they work correctly with the quadratic hexahedra?
I'm not sure about VTK 4.2, but I have used ParaView with more recent
versions of VTK and I believe it does use all of those classes. The only
one I am not sure about is GeometryFilter -- ParaView may use a
DataSetSurfaceFilter instead. You might try swapping those out to see
if there's a difference.

        David