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View Full Version : what is correct technique for "GI" and "FG" calculation ?


zelda64
10-29-2009, 11:53 PM
Hello , I am a new user and beginner in maya and mentalray.
I have a question about rendering in mentalray.
I hope you can guide me.

when my animation has only camera moving and any object has not movement in it (fly through) ,I calculate GI once for the whole scene and I save it.

(image No1)

http://www.freeimagehosting.net/uploads/b002058a40.png (http://www.freeimagehosting.net/)

then I set render mode in "Render Final Gather Maps" and I set "Rebuild" option for "Final Gathering" on "Off" and I calculate "FG" for some frames of animation.

(image No2)

http://www.freeimagehosting.net/uploads/64965cb779.png (http://www.freeimagehosting.net/)

then I set "Rebuild" option for "Final Gathering" on "Freeze" and I also uncheck "Rebuild Photon Map" . (because I want to use saved "GI" and "FG") and I finally set render mode in "Full Render" and I can render only animations with camera moving and without object's movment , easily.

(image No3)

http://www.freeimagehosting.net/uploads/957b2e06b9.png (http://www.freeimagehosting.net/)

but when I want to render an animation with object's movment, I have to render "GI" and "FG" in "Full Render" mode for all frames therefore render time will increase. such as a runner character layer rendering.

(image No4)

http://www.freeimagehosting.net/uploads/73e0c374e4.png (http://www.freeimagehosting.net/)

My Question :

is there a better technique for "GI" and "FG" calculation in an animation with object's movment?

or

what is correct technique and true method for "GI" and "FG" calculation in an animation with object's movment by mental ray and maya?


thanks.

InfernalDarkness
10-30-2009, 04:40 PM
is there a better technique for "GI" and "FG" calculation in an animation with object's movment?

or

what is correct technique and true method for "GI" and "FG" calculation in an animation with object's movment by mental ray and maya?

In 2009, there is an option under FG for animation optimization.

The "correct technique and true method" would be to rebuild your maps for each frame, if you're going for accuracy.

zelda64
11-01-2009, 01:05 AM
thanks InfernalDarkness.

Galakgorr
11-02-2009, 07:24 PM
i usually try to avoid using GI in animations... it's way too expensive to calculate and not get flickering.

try using a very broad FG setup... maybe 150-200 accuracy and a point interpolation of 50. it won't be very precise and you will get some light leaking into dark corners, but you can just use your AO pass in post to multiply against it. it's also very very fast to calculate since you're not using many FG points at all.

zelda64
12-09-2009, 11:38 PM
thanks Galakgorr

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