[vtkusers] vtkCellPicker question

[Stephen Langer]

Hi --

I'm using a vtkCellPicker to select cells in a tetrahedral mesh.  Sometimes the point returned by vtkCellPicker::GetPickedPositions is on the near side of the picked tetrahedron, and sometimes it's on the far side.  Changing the position passed into vtkCellPicker::Pick by only a pixel or two will cause the returned point to switch sides.  Is it possible to force the picker to return the point on the near side, or at least to return both points?  I'm really interested in identifying the nearer triangular face of the tetrahedron, but my vtkUnstructuredGrid contains only tetrahedral cells.

Thanks,
    Steve

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