View Full Version : please help indirect lighting

11 November 2009, 05:47 PM
hi everyone,
I am working on my student film and am at the rendering stage now. I have rendered images using fg and gi in mental ray for maya before. but i've been told it'd take too much time if i use that for my entire animation ( I guess so :( )

looking around threads, I have got the idea that one can fake fg with ambient occlusion. but all i manage to do with ao is enhance details and add smooth shadows.I dont think it can create indirect fill lighting (Correct me if i am wrong here).

so my question is what is the best workflow for creating indirect lighting? should i use fg? should i fake it with a plugin like gijoe? or should i somehow fake it with ao?? which would be most efficient approach??

thanks a lot for going thru this.

- regards

Also, is it better to use mr's inbuilt ao mia ao shader or something like dirtmap?

11 November 2009, 06:41 PM
It really depends on what kinds of imagery you intend to make, but FG is a great tool for indirect lighting. You can animate with it just fine. GI is a bit more render-intensive in mental ray, but FG works for 90% of the time you need indirect lighting.

I always use the mia_material_x's AO, which you can apply texture maps to just fine if you need to.

11 November 2009, 06:11 AM
Thanks sho pi,

I am using fg with a dome textured with surface shader as the light source. wrks great. And im using mr's mia texture plugged into a surface shader for ao. strangely, maya's render layers' preset for occlusion does the same thing but ends up taking 4 times the render time....wnder y!!!

one more question though, is it a better solution to use something like gijoe if all i want is fg and no gi in my scene??

thanks :)

11 November 2009, 06:36 AM
GI Joe is a Global Illumination replica, using multiple lights as your sky. It's not necessary if you have mental ray. Used to be that using a few lights was faster than true GI or FG, but with modern computers just using MR indirect illumination is fast enough and looks much, much better.

11 November 2009, 08:11 AM
great to know that....:)

thanks a lot man.uve been a great help.

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