View Full Version : GI setttings for animation.
01-25-2006, 11:25 AM
Just wondering what GI settings everyone else uses for animation, i.e. best trade-off between eliminating GI noise/jitter vs render time. I tried all the suggestions in the manual and settled on a sampling level of 4x4 and primary ray count of 400. No secondary rays and other settings at default.
I didn't see any GI noise/jitter in any of the animated GI samples in the gallery section and wondered what settings were used.
I asked this over at the official EI forum but everyone seems to be hanging out here and I really would like to know how everyone else is making GI work.
P.S. I'm certain my jitter is not due to aliasing issues since it goes away when I disable GI.
01-25-2006, 12:58 PM
Yeah jittery lighting is a side effect of ray based GI solutions (the alternatives all have their own problems).
I didn't do any of the GI animations in the gallery so I can't comment on their settings but I think it just depends on the project, if you have simple geometry then a low ray count will do, obviously the more complex your scene the more rays it will need to light it satisfactorily, in one test I did here I needed 900 rays to get rid of the jitters - in another I needed only 100.
Changing the sampling area to 4x4 is a great help in reducing them so spot on there, and you're right about secondary rays, unless you have a render farm the size of Angola then avoid them while animating (obviously unless they are essential to what you are trying to achieve).
In my experience changing the sampling area to 4x4 from 8x8 is more efficient at getting rid of jitters then upping the ray count. "Render adjust, render adjust" ;)
Just as an aside to solving jitters, when animating I only ever use 1 bounce for RI, in a moving image of PAL resolution you simple can't tell the difference.
GI animation, is a balancing act.
For animations, I don't use Reverse illumination very much, and never use secondary Rays in the GI Options.
If I need secondary rays I use a light with GI mode set to secondary, much faster.
You can take a look at a project of mine @ http://eias.groothuis.com/ The Blikjes animation benchmark is how I setup most GI animation projects.
With the GI sample level I usually stick with the 8x8, and for most scenes a raycount between 150 and 300 should be enough.
01-25-2006, 05:12 PM
I was wondering, when you use the 'Secondary GI mode" light trick, do you know if the secondary rays become as fast as the primary rays?
I haven't experimented with that yet, I will tomorrow though if I get some spare time..
The rendertimes with secondary rays depend a lot on the specifics of the scene.
The first tests using the light with GI mode set to secondary blew me away. In most scene's it has only very little effect on the rendetime, by using secondary Rays in the GI Options the rendertime can multiply by big numbers, this makes it often unusable for animations.
If I remember it correctly, I think the blikjes benchmark renders 1 frame in about 4 minutes, and by using secondary Rays in the GI Options it was almost 30 minutes.
The weird thing is that I think scenes with a light with GI mode set to secondary look better than using secondary Rays in the GI Options.
01-25-2006, 08:01 PM
Very very cool, I'll be sure to do some experimentation with this! :)
In addition to what Hans has said I was told that setting the color tolerance to between 2.5 and 10 and using sampling of 4x4 reduces noise. I used these types of settings on my last 2 projects and got decent render speeds and quality(minimal noise).Samples below 4x4 take too long but do make the noise smaller.
Models ranged between 500,000 and 3 million polys and I had render speeds between 2 min 2 seconds and 20 minutes per frame depending on the proximity of the detailed (high poly count) part of the models to the camera.
So far the 2.5 setting for the color tolerance seems ,at least with the renders I've been doing, to produce consistantly good results.
Other settings have been 150-400 rays( if render appears to have semi static blotches up this count), never more than one bounce (results take longer and difference is almost non existant), never use secondary rays, exclude transparencies from GI solution, and never set any of the energy bias or intensity settings over 1 unless you are looking for an unusual effect.
Additional note: to increase the bounce light if needed create a separate light that is GI only and up its intensity in the light setting. this way you get lots of bounce without blowing out your bounce surface.
Anyway, this is all I can remember at this moment. Hope this helps.
01-27-2006, 07:24 AM
please to see EIAS in cgtalk :)
I use 200 rays, Secondary 0 as Hans said, GI SL 8x8, sky on =1, 1 bounce, color tolerance 2.5.
I tried a lotta different color tolerance and i found more important to put a texture to all objects and avoid using only color while texturin.
Also exclude glass in GI panel in order to speed the render, (i did it even whit trees).
01-27-2006, 07:37 AM
Welcome! Thanks for visiting..
01-28-2006, 09:13 AM
Increasing the tolerance is great for still work, but in animations you have to be careful because it has a tendency to just swap the jitters for noise.
Depends if you can get away with it I suppose :)
02-01-2006, 10:56 AM
It's great to read about the various settings.
Are these settings derived from trial and error or another
02-01-2006, 12:09 PM
Trial and error & educated guesses... unless there is a big secret I'm not in on....
Dun dun duhhhhh.... :eek:
I use the secret button :)
02-01-2006, 06:18 PM
Trial and error it is...thanks.
02-01-2006, 06:18 PM
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