[vtkusers] Check if point is inside convex hull

[Dirk]

Dear list,

Lets say I created a convex hull H of a point cloud with vtkDelaunay3D.
I have a point A.
What's the best way to find out whether A is inside H, 
on H or outside of H?
How do I get the id of the tetraheder in which A lies?

Thank you,
Dirk