Shadows (Yet Another Object Graphics Question)

["Jason P. Meyers" <jpm7934(at)cis.rit.edu>]

Hello All,

	I learned my lesson with the Orb/sphere thing.  Before, I try to do
things the hard way, I'll pose the question and see what surfaces.

Does IDL support casting shadows caused by one object onto another, for
example a ball over a ground plane?  Here is what I am doing:

1) I created two spheres (using the orb object)
2) I place them in 3-D space according to some user specified params
3) I "tether" them to the origin with a polyline
4) I display some axes (centered on [0,0,0])
5) I create a white ground plane just under the x & y axes (i.e. z=-0.1)
6) I place it all in an IDLexObjView object (I love being lazy!)
7) I display it in a draw widget

This all works nicely.  However, I would like to see a projection (i.e.
shadows) of the spheres (and tethers too) in the ground plane.

If I can't do this, my current idea is to draw two more lines and a pair
of
circles on the ground plane.  I have all the data necessary to do this. 
But
if something line MyView->TurnOnShadows exists, I would be all for using
that!

As always, I am open to any suggestions and thank you in advance.

-- 
Jason Meyers
Ph.D. Student, Center for Imaging Science
Rochester Institute of Technology
jpm7934@rit.edu