[vtkusers] Problem With vtkUnstructuredGrid, displaying 3d elements

[David E DeMarle]

Most data types are converted to vtkPolyData, ie the surface is
extracted and drawn, before rendering a you have observed.

To see inside the voxels, tets and other volumetric cell types, you
might want to check out the volume rendering classes in vtk, which can
draw the data directly.

If you want to see the wireframe of the data which shows all of the
internal cell edges, I think you have to write a new filter, or add an
option to vtkDataSetSurface filter. I looked quickly through the vtk
doxygen and no classes seemed appropriate. The filter would be pretty
simple. It would be a DataSet to PolyData filter, in RequestData it
would:

copy all the points in input data to output data
copy all point centered data likewise
for (i in inputcells)
  new cells = triangulate inputcell i;
  add new cells to the output data

Then you could draw that in wireframe mode.

cheers,
Dave DeMarle


On Mon, Jul 14, 2008 at 1:12 PM, Robert Caldwell
<allan.caldwell at mail.mcgill.ca> wrote:
> Hi,
>
> I'm working on improving someone else's program for viewing Finite element meshes. The problem I'm working on is that when a 3d mesh (tetrahedral or sometimes hexahedral, 4 nodes per element). Is put from my data structure to the vtkUnstructuredGrid structure and rendered, the only a skin mesh (2.5D with either square(from hexahedral) or triangular(from Tetrahedral) elements showing the outer surface) is displayed. I think it is some sort of filter to improve performance, or I'm using the wrong Class. Has any one encountered this before?
>
>
>
> -Robert  Caldwell
>
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