[Algorithms] Stopping shadow volumes from going through geometry

[Fong, J. <JF...@Bl...>]

Hello,
 
I was wondering if there is some way to prevent shadows, generated by the
stencil shadow volume technique, from being extruded through other objects
in the scene?  e.g. a character standing on an overhanging ledge above
ground casts a shadow on the ledge but also onto the ground below the ledge.
 
I thought about clipping the extruded shadow polys against the world
geometry but I'm hoping for a more elegant (i.e. simpler) solution since our
world geometry is quite dense.
 
Any solutions or links/pointers to papers related to this issue would be
much appreciated!
 
Thanks,
Jay