Determine if face is covered by shadow

[pelvis]

Hi,

I am trying to check (in Ruby) if a face is covered by shadows or not. If possible I would like to compute how much of a face that is covered by shadows, but if this is too complex or impossible I would like to know if a face is partially or fully covered by shadows.

Have been unable to find the answer to this one in the forum so far, appreciate any help I can get.

Thanks in advance,

Pete

[TIG]

I wrote this last year http://forums.sketchucation.com/viewtopic.php?p=371243#p371243 'ShadowProjector'
If calculates shadows cast on faces and % area etc

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