[vtkusers] vtkImplicitDataSet from vtkPolyData?

[Theodore D. Sternberg]

I'd like to clip against the surface defined by a vtkPolyData.  I suppose 
one approach would be to create two auxiliary surfaces on either side, 
assigning the values -1, 0 and 1 to the respective surfaces' scalars, then 
pass those on to vtkImplicitDataSet, letting ImplicitDataSet interpolate 
scalar values between the cells of the actual surface and the two 
auxiliary surfaces on either side of it.

But is there any easier way to do this?

Theodore Sternberg
Lawrence Berkeley National Laboratory