Vray for Anmiations

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  02 February 2013
Originally Posted by Panupat: Thanks for sharing! Do you use Nederhorst 100% adaptive settings? Or do you prefer to control brute force subdivision by yourself with this workflow?


Since the new vray version (since version 2) its not recommended to use 100% adaption anymore. More something like 90-95%.
 
  02 February 2013
Originally Posted by Panupat: Thanks for sharing! Do you use Nederhorst 100% adaptive settings? Or do you prefer to control brute force subdivision by yourself with this workflow?


Adaptive settings are becoming irrelevant after some point because you are switching from doing adaptive sampling on shader level to image sampler level. When I use BF my DMC settings are usually pretty high like 1 min and 50 max, and only thing you need to tweak at this point is image sampling threshold since every single sampling that uses subdiv in scene is casting only 1 ray (shadows, reflections, refractions etc.)

Last edited by InTerceptoV : 02 February 2013 at 10:51 PM.
 
  02 February 2013
Originally Posted by InTerceptoV: Adaptive settings are becoming irrelevant after some point because you are switching from doing adaptive sampling on shader level to image sampler level. When I use BF my DMC settings are usually pretty high like 1 min and 50 max, and only thing you need to tweak at this point is image sampling threshold since every single sampling that uses subdiv in scene is casting only 1 ray (shadows, reflections, refractions etc.)

Isn't that horrendously slow? When you're only taking one secondary sample per primary sample, you get really bad stratification, and you need significantly more samples per pixel. It also increases the risk of completely missing features, since the adaptive system is based on local contrast. If no samples in a given area of pixels hit anything, then it won't know that it should sample it more, which makes it a bad method for resolving small geometric detail.

My knowledge about practical use of V-Ray is not as deep as it could be, but generally speaking it's better to take fewer higher quality samples, rather than more lower quality ones.

If you have a scene with a single point light and a single area light, and the area light needs all 50 subdivs to resolve properly, with this method you'll have to fire all 50 subdivs worth of primary samples, resulting in 2500 camera rays per pixel, plus 2500 shadow rays to the point light, plus 2500 shadow rays to the area light, for a total of 7500 rays per pixel. If you instead set the sampler to, say, 2:8, you'll get a total of 2628 rays and pretty much the same quality, since it's unlikely that you'll need more than 64 primary samples in the first place.

Using the adaptive anti-aliasing as a brute force method for clearing up render noise is easy, but it's not a very fast method.
 
  02 February 2013
Actually this method of relying completely on DMC sampler works very good and produces fast results. As I said, we used that on many projects while I was at Blur so it's tested in production. The only thing is that sometimes if I had DMC set to 1 50 I would set BF samples to 100 to 150 which basically gives 4 or 9 samples of glossy reflection per shading sample (non adaptive). This was for situations where we had highly reflective surfaces and reflection was priority over image sampling.
I remember presentation that DD did about their work on Tron and they basically used same techniques, relying completely on DMC sampler to solve noise problems.

When I started doing these experiments I was also a little bit sceptic about final results and render time, but after trying it over and over again it became my primary workflow. However, this was only used for moving objects, while static ones were rendered as separate pass and with different settings bcause GI was cached for those.
 
  02 February 2013
Originally Posted by InTerceptoV: It's very simple... bruteforce for 1st bounce and LCache for secondary. It works perfectly!
When I was at Blur I used this constantly on characters and it made my life much much happier compared to Mentalray pipeline we used years ago. The only thing is that you need to know how DMC works if you plan to use BForce GI.


So you precalculate Lcache for that? or per frame? also how you compensate for the GI for static environment objects which you are doing as seperate pass? how do you get that GI bounce in your scene with only characters?
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  02 February 2013
Can i suggest you have a look at the thirdparty plugin written for Vray called Solidrocks? Ill admit, i have never used it, but have heard good things. Vray is certainly very well proven in the industry and has managed to still be going strong when Brazil and Finalrender have pretty much dissppeared.

Getting flicker free animations is still a bit trial and error with it though and a technique that works for one scene might not work for another. Personally, i render a IR pass and then use it in the final render. Seems to work so far. Speak to the guys on the forum, i know one of the founders, Vlado, is still quite active and always helpful.

Good luck.
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  02 February 2013
Originally Posted by InTerceptoV: Actually this method of relying completely on DMC sampler works very good and produces fast results. As I said, we used that on many projects while I was at Blur so it's tested in production.

Interesting. I'm going to have to try it.
 
  02 February 2013
Originally Posted by InTerceptoV: The only thing is that sometimes if I had DMC set to 1 50 I would set BF samples to 100 to 150 which basically gives 4 or 9 samples of glossy reflection per shading sample (non adaptive).

I remember presentation that DD did about their work on Tron and they basically used same techniques, relying completely on DMC sampler to solve noise problems.

When you said "relying completely on DMC" you're setting the adaptive amount very high? I'm curious because if the BF samples can still kick in, this value has to be lower than 1 right?
 
  02 February 2013
When you use the adaptive settings, i also strongly suggest you set the minimum subdivs of the adaptive image sampler to something higher than 1. It does improve quality quite a bit.
 
  02 February 2013
These are the settings I always used at Aardman. I just used these as a preset and never had any problem with flicker. Also I found the render times pretty decent.

http://predmondvfx.wordpress.com/20...ction-settings/
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  02 February 2013
Originally Posted by patrickrowan: These are the settings I always used at Aardman. I just used these as a preset and never had any problem with flicker. Also I found the render times pretty decent.

http://predmondvfx.wordpress.com/20...ction-settings/



thanks for sharing the settings, but don't you get the fine grainy noise with brute force solution?
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  02 February 2013
These were just the base settings that usually worked. There not feature film settings as renderman was used for the last one. If there was still noise I would use a denoise in nukex, lower the adaptive samples or tune the brute force samples. A lot of the time the noise was acceptable.
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  03 March 2013
I know it is also possible to get the fake GI look with vray using 3 point lighting key, fill etc. and AO. it was the old method but I still don't find any good tutorial who can explain this process with production in mind. because this is a very good shortcut when ray tracing isn't working or too expensive to calculate mainly for animations.
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  03 March 2013
Originally Posted by bkravi: I know it is also possible to get the fake GI look with vray using 3 point lighting key, fill etc. and AO. it was the old method but I still don't find any good tutorial who can explain this process with production in mind. because this is a very good shortcut when ray tracing isn't working or too expensive to calculate mainly for animations.


In Maya, create an ambient light, add a VRayDirt in the ambient light.
Enable environment mode in the VRayDirt.
 
  03 March 2013
Originally Posted by bigbossfr: In Maya, create an ambient light, add a VRayDirt in the ambient light.
Enable environment mode in the VRayDirt.


so you plug vraydirt in color node of ambient light? or somewhere else?
environment mode means the environment of GI or only the surrounding objects?
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