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# 1 07-10-2002 , 08:51 AM
Jim's Avatar
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Join Date: Jun 2002
Location: Adelaide Australia
Posts: 201

Mental ray _GI and final gathering settings????/

Hi all,

Just curious to find out what types of settings people are using for 'Production' Quality (in Mental ray for Maya settings) to achieve decent but not too slow GI renders?


GI accuracy ??????
GI size????

Final gather accuracy ????
Final gather size ????

This would be very useful as I'm currently using a P3 450 which for this sort of stuff is extremely slowwwwwwwwww..

re Jim

Mayan elder......only in years.....
# 2 07-10-2002 , 09:54 AM
Registered User
Join Date: Sep 2002
Posts: 10
if you don't need real acurate gi solution , try to use Final Gather alone (settings depend of your scene).
you will get a gi like effect (color and light bleeding) for a really shorter time

# 3 07-10-2002 , 04:55 PM
undseth's Avatar
Join Date: Aug 2002
Posts: 1,135

Im still a newbie, but if you use mentalray when doing ONLY FG, you would (best i think) want to push the accuracy to over 1000 (1000-4000).

-With min-radius equal to a tenth of the max-radius;
If you dont get the results you like, try these settings;
Min-radius = 0.01
Max-radius = 0.1

or even better

Min-radius = 0.01 (or 0.001)
Max-radius = 0.01

-If radius is set too low, it produces a "low-quality-jpeg" pic, i think. (correct me if I am wrong)


-For production results with GI ALONE, i usually push accuracy to max (usually 30000, on my machine).

-Radius can be set automaticly by setting it to 0.
-Raduis is relative to scene size i think.
-Else try to testrender, and start off with small radiuses, AND exposure to 1 (not 2 like in "realistic exposure")
-The exposure = 1 lets you see more clearly the size of the area lit by the individual photon.
-If you increase the number of photons in a shoot, i guess the radius can be smaller, contra a scene with fewer photons.

I have tried this once but i do not render much these days. And I am NO expert in mentalray (hard to find anything useful on the net, unless you code you shaders yourself i feel).

-With limited processor power/time, I think I will explore the combo solution sometime in the future. Meaning a "medium" FG WITH a "medium" GI, a little of the both.

-Still FG radius would have to be set good, i think.

-GI accuracy setting can be lowered good, but not the radius, i think.


-FG accuracy setting can be lowered good, but not the radius, i think.

I think this would produce decent renderings in shorter time. But let me know if you want to add anything, as I am puzzled by mentalray settings myself.

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