[vtkusers] ImplicitFunction from vtkPolyData?

[Prabhu Ramachandran]

>>>>> "TDS" == Theodore D Sternberg <tdsternberg at lbl.gov> writes:

    TDS> I'd like to clip one vtkPolyData against a (non-planar)
    TDS> surface defined by another vtkPolyData.  Image the first
    TDS> vtkPolyData is the Earth, and the second vtkPolyData is the
    TDS> shape of an impact crater; I'd like to show the Earth with a
    TDS> crater in it.

    TDS> To do this, I think I need a vtkImplicitFunction to pass to a
    TDS> vtkClipPolyData.  Is there a good way to obtain the necessary
    TDS> vtkImplicitFunction from that second vtkPolyData?

I dont know of a way to do exactly this but take a look at the
vtkSelectPolyData class.  It lets you define a loop on your PolyData
and then lets you select everything within or outside that loop.
Maybe you can use it to do what you need.

cheers,
prabhu