Q: Isosurface pipeline ???

[Audrius Stundzia]

Dear vtker's

I would like  to compute an isosurface of the scalars S = S(x,y,z)
associated
with a structure point data set.

I'm using the following pipeline to try to generate such an isosurface
from
a 128 x 128 x 23 slice data set.  I've loaded and displayed the 2D
slices without
any problem. Now I'm trying to generate an isosurface. So far without
success.

The pipeline.

   vtkScalars

   vtkStructuredPoints

   vtkImplicitVolume

   vtkSampleFunction

   vtkMarchingSquares

   vtkPolyDataMapper

   vtkActor

The vtkScalars object is loaded into an vtkStructuredPoints object

points->GetPointData()->SetScalars( scalars)

The above pipeline gives me a blank screen (just background).

Are the scalars passed down the pipeline?
What methods should I use to make that they are and that
their isosurface is calculated?

In the VTK 2nd ed. pg. 508 example:

Why in the vtkPolyDataMapper object is the following method used?

skinMapper->ScalarVisibilityOff();

Similarly, in the pg. 520 example, the vtkMarchingCubes object uses the
following method.

mcubes->ComputeScalarsOff()

Why?

Any pointers (pun intended) would be most appreciated.

Audrius Stundzia

IBMG



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