[vtkusers] Interpolating point on a surface

[Kenneth Porter]

I have a point cloud representing a deformed plane. I run this through 
vtkDelaunay2D to get something I can render. I'd now like to be able to 
plug in arbitrary XY values and get the matching Z. (Not a rendering 
problem. I just need the single point computed.) Is there a class that will 
do this?

Here's an example rendered with ParaView:

<http://sewingwitch.com/ken/Stuff/Surface.png>