[vtkusers] Picking invisible object...vtkPlane ( Simple version ! )

[Charl P. Botha]

On Tue, 2003-07-22 at 14:14, Sebastien Auclair wrote:
> The vtkPlane's normal is not always parallel to the display plane's normal.
> In which case the returned value (vtkPlane::ProjectPoint) is always correct.
> The more perpenticular the vtkPlane's normal is in relation to the Display
> plane's normal, the less accurate the intersection coordinates becomes. (It
> should be the opposite !)
 
Why?  The more perpendicular the vtkPlane's normal is to the view plane
normal, the more perpendicular the vtkPlane is to the view plane, which
means that your projection point will shoot off to infinity or miss the
plane completely.

You're probably going to have to solve this problem by yourself by
analysing the source code and first manually doing the math that is
being implicitly performed by your VTK calls to see where your
understanding and the code diverge.

-- 
charl p. botha http://cpbotha.net/ http://visualisation.tudelft.nl/