HELP: lights will not cast through glass material or any material that is transparent

this has been really annoying me when trying to light this simple room I cannot get the light to pass through my window, I've tried every type of light as well as mental ray the only time it seems to work is when I choose ray traced shadows but I don't want to use that as it produces very hard edges. Strange thing is it will show the light passing through in the viewport but when rendering it doesn't. Any help would be appreciated.

Thank you

Sounds like a material issue.

Can you post a screen shot of your Glass Material Settings?

ye sure here they are I didn't change anything on any of the settings its just the mental ray arch and design think glass I haven't modified it in anyway and when I did to try and solve the problem ive come up empty handed

Do you windows have thickness?

no not at all in fact it seems that light will not pass through any object that has transparency when rendering buy again shows up fine in the viewport so perhaps a render setting is the problem ?

no not at all in fact it seems that light will not pass through any object that has transparency when rendering buy again shows up fine in the viewport so perhaps a render setting is the problem ?

Ok, then I won't be of any help, since I don't know mental ray that good. Hopefully someone else can help you out!

Its been a while since i used mental ray, but perhaps this is the solution?:

"If you are using Final Gather with a transparent surface, you may need to increase the FG trace depth values in the Render Settings window."