[vtkusers] Cutting UnstructuredGrid (updated)

[Hongyu Wu]

Hi, 

I am sorry in the last message I incidentally left out the word "than" in
the sentence "I got a seg fault ... with normals other than (0, 0, 1)"  --
that might have caused confusion.   

So, let me describe my problem again here. 

I am trying to visualize my FEM UnstructuredGrid results -- displacements
and stresses. My cell type is VTK_WEDGE(13). I have been successfully
showed the displacements with WarpVector, stress tensors with
TensorGlyph, and effective stresses with colors throughout the whole 
grid. Also, when I tried to show a horizontal slice across my grid (using
vtkCutter) with a plane of normal (0, 0, 1), I got correct cutting
display. But when I tried to cut the grid with normals other than (0, 0,
1), say, (1, 0, 0) or (0, 1, 0), I got seg faults.

My platform is Linux on i686, VTK 3.1 with MesaGL 3.0. Tcl/Tk 8.0. The
Plane and Cutter are defined as:

vtkPlane plane
    plane SetOrigin 1500 1500 500
    plane SetNormal 1 0 0
vtkCutter planeCut
    planeCut SetInput [reader GetOutput]
    planeCut SetCutFunction plane


Further, I reduced my grid from 3409 points to 532 points and tried 
again. This time, when I used a plane with normal (1, 0, 0) or (0, 1, 0),
I didn't get seg faults and could see the visualization. But there were
some errors -- the cutting plane was not continuous cross some wedge 
cells. Instead, in those wedge cells, the result cutting plane display
went from one intersection line directly into infinity.

I suspect the intersections of some wedge edges with the cutting plane are
set to infinity somehow. 

Does anyone have any ideas how to fix it? Thanks a lot.

  -- Hongyu