shadows through glass

I have a glass canopy structure lit from above. I’m not able to get my shadows to reflect the transparency of the glass, in other words, the glass is casting the same density of shadow as the opaque structure. How can I adjust the glass to cast less dense shadows? Thanks. Harold

Turn on affect shadows in your glass material. Alternatively turn off cast and receive gi for the glass objects if it’s very clear glass - you’ll get a good speed up.

could be this as well

http://www.chaosgroup.com/forum/phpBB2/viewtopic.php?t=17187