[vtkusers] How to get the visible face?

[David.Pont at ForestResearch.co.nz]

Hi Larry,
   you could traverse all cells, get or calculate a cell normal and use dot
product with camera vector. To handle occlusion would be more tricky...
  Dave P


|---------+---------------------------->
|         |           "Larry"          |
|         |           <larry74 at 163.com>|
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|         |           23/04/2004 02:10 |
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  |       Subject:  [vtkusers] How to get the visible face?                                                                        |
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Hello, everyone!
Suppose I have a polydata, which is consisted of triangles, I'd like to get
the faces which can be seen by the camera.
That's to say, there is a point M, and an object whose faces is a set of
triangles, How can I get the faces that can be seen by the point M? and how
can I get the faces that is not seen by the point M?

Thanks!
Larry
_