Brute Force animation

[xjapanese]

Hi Guys,

 

I need your experience while rendering animation and using Brute Force.

I have so far always used IR and LC but as I need complete flickering free animation and decided to test BF this time>

What are the important things one might consider when Rendering Brute Force and LC.

How low to you go on the image sampler?

What other things one might consider.

 

Thanks!

[Chris MacDonald]

When you go brute force it becomes a lot less about settings than irradiance map. You simply have to choose between noise & render times.

[Francisco Penaloza]

Well first you'll need more rendering power, or more patience because your rendering time will be longer.

VRay 3 is a lot faster brute force wise but still, going brute force is not about speed during rendering time, it is about convenience with moving objects and setup time; also quality gain.

You need to be ready to trade a little noise as mentioned by Chris. Needless to say when camera moves, the noise become more forgiving of what you think so a few test will give you a good idea of how much noise you are willing to accept in your scene.

 

If you are using V Ray 3.x I will recommend to play a little with the shaders rate and antialising values. I know Chaos group recommend to not push shader rate more than 6 but honestly with some scenes it render a lot faster if I increase this value and reduce the antialising. But this of course depend of the scene. if you have large scattered areas with many small object, you'll need to increase your antialising over shader rate. Also LC may be a little fleaky in that scenario you may need to go full brute force. On exteriors is not that bad, believe me.

[xjapanese]

Hi Francisco,

 

Thanks for the answer and tips .. what do you mean by "little freaky""..yes you are right about the antialising...but on the post wireframe channels sometimes get strange selection if antialising is reduced..I will test again..

 

Thanks Chris too!

[Francisco Penaloza]

If you are working with complex displacement, or large areas of it, LC start to use a lot of RAM also get affected with many instances such brass, trees and in general very large scenes. Also with fast moving object it create weird noise. Over all in the latest version of V Ray it been less but the RAM usage it is consisten, but that because the way LC works.

Just things just to consider while you are working

[xjapanese]

I see.That is very good to know.

What about using any image filter is needed does tha pattern of the niose smooth out possible flickering issues?

 

DO you go lower than 0.01 on antialising and noise trish?

Edited May 13, 2016 by xjapanese

[xjapanese]

Usually 1.8 Area image filter does good job for animation but is there a way I can save that extra time from the renders turn it off and have the soften effect in AE:...

[Francisco Penaloza]

Antialising filter I use area or VRay lanczos, while this do not affect "much" the image if you are rendering very large sizes, it will help the noise threshold to define contrast areas. Vlado recommend to use VRay lanczos in default values, but Area works pretty good most of the time for animation.

If you have very small objects, such grass far far away trees or cars, then you may need to increase your bottom value of antialising, default is 1, you can use 2 instead of moving antialising filters values.

 

noise threshold is per scene basis, yes it can get bottom 0.001 or 0.005 or o.01 depending of your scene and how much light you have on it.

 

When less light or using HDRI you need more samples or lower threshold to clean noise.

[xjapanese]

Thanks ..

 

and sorry when you render Brute Force do you render the ligght Cash separately?

[xjapanese]

I am a liitle lost i get the same time if I do IR and LC ( prepass way..two times slower than the ir lc single frame normal mode) ...compared to BF and LC ...

 

would precalculating LC slow things ?

Edited May 16, 2016 by xjapanese

[Francisco Penaloza]

BF always will be slower to render to get same clean result compared to IRR.

 

In animations depending of your scene you can pre-calc you LC pass, (it only calculate one time) or use the camera path function,or do not pre calculate at all. This last option may cause some flickering. It get diminished if you use the camera path option, and way less if you save the LC as pre pass. if LC is taking too long to cal may be memory issue, as mentioned early, in that case you may need to go Brute force brute force.

[xjapanese]

Hi Francisco,

 

Yes I know it should be ..but I am getting strange results..Iam following vray tut step by step :

http://docs.chaosgroup.com/display/VRAY3MAX/Rendering+an+Animation+with+Moving+Objects+II

 

and with IR and LC I am getting 16min per frame and it has some awful artefacts and flickering ..while BF and LC is 18min and looks better almost flicker free ( will precalc the LC to see how it will help) ..

 

I am starting to get lost ..why IR LC interpolation prerender

gets such a long time to render when it is not doing anything

[Francisco Penaloza]

You said Irr+LC is 16 min and Brute force+LC is 18min. So what the problem IRR+LC still faster, 2 minutes per frames, Flickering, may be caused for different factors, maybe too low settings, etc etc.

 

With Brute force you won't get GI splotches, they are transformed to Noise. is that what you mean?

When you pre cal IRR and LC you are only saving GI generation, all the other calculation, glossiness, antialising, bump, displ and others are calculated during renderings.

 

What are you trying to render any ways.

[xjapanese]

OK yes I agree but small difference..well I will upload tomorrow..it is just that trees( it is an exterior scene with trees ) leavs are "boiling" doesn't look like noise to me..but will try with higher settings...now is color tresh 0,01 noise tresh 0.005 ...

[Francisco Penaloza]

well depending how far the trees are from camera it may be the radius of you IRR or LC size.

In that case Brute force will be better.

any ways you may need to increase your AA

[xjapanese]

yes I am tetsing all these still...

 

I am reading an old thread about opacity flickering:

 

""In the end if your deadline it coming at you too quick to really spend the time discovering the solution, try Brute force with 12-16 subdiv Light Cache on single frame and 800-1200 subdiv. If you un-tick the time indepence box any noise will be like film grain."

 

where is that " time indepence box" in vray 3.2 can't seam to find it?

[John Dollus]

Time independence was renamed to 'lock noise pattern'

[xjapanese]

Would that make it look better if it is "on" to make it look less like flickering but in real life and film it is not locked ?

[xjapanese]

on BF and BF as second I am getting boiling trees again opacity is without filtering too..so maybe antialising is the only thing left ..0.005 should go to 0.002

[Francisco Penaloza]

Yes as mentioned by John now is called lock noise pattern. Antialising on trees is always a pain and besides the noise threshold you need to increase your Antialising samples.

Use the samples pass, if the leaves are too red and look noisy, you need more samples not reducing the threshold, if the leaf are blue and noisy, then you need to reduce the threshold.

 

By default in V Ray 3 antialising is set to 1-24 you should try, 2-18 or so, maybe 3-18 with an minimum shade rate of 8 or 10.

Per VRay documentation, when you have high frequency element AA will be better than minimum shade rate. By experience it has to be a mix of both.

 

You could also select the trees and change the subdiv multiplier for that tree only,(right click on the tree and VRay properties) that way you don't waste AA on the rest of the scene. This make seance because usually trees are the last think to clean up.

 

Having said all that, remember that on Fly thru you should use some motion blur to avoid image jittering, and this will eliminate some of the tree boiling effect too. As mentioned at the beginning, using Brute force is a trade of how much noise "is acceptable"

DOF and motion blur, will cover lot of that. I am not talking in a none seance use of it, just natural blurriness will go a long way.

 

what are your setting over all?

How far are you from the trees?

How fast your camera moves?

[xjapanese]

50m-80m..camera is moving realling slow..subs of materials mostly are 64 sub ( reflectionwise) ..they do have translucensy on ( some refract 16subdiv) ..

 

 

mind shade rate :2

divide shading subdivs:on

 

adaptive image sampler:

min: 1

max:4

col treshold 0.01

 

dmc

 

min samples : 16

adaptive 0.85

noise treshold: 0.005

 

 

 

I will maybe try and render people separatley ..and now test IR and LC optimisation again ..

[Francisco Penaloza]

Without knowing your scene it is kind of hard to know what setting you'll need to adjust, but for start, if you are going brute force, and not the new simplified method on VRay (minimum shade rate). I believe your AA setting are low.

as mentioned in other post, with trees and landscaping you need to increase your AA.

Something on the neighborhood of 2-24 may work. maybe you can get a way in one aerial with 1-16 but this depend of your scene.

Also keep an eye if you are setting your scene old style be sure to give enough samples to the brute force it self.

[xjapanese]

Hi Francissco,

 

THanks a lot !!! That was it antialising 2/24 almost gone maybe I will try even higher ..Definetely I had very poor understanding of AA..I used to control it only via noise treshold...

I will render people separately ..what will be the best way to do that?..I am used to work with lightwave not 3ds max and vray they I had them as trga separate channels all objects but I don't think that is possible here

[Francisco Penaloza]

Well if you are using brute force you don't really need to render then separate, but if you want extra control then you'll need to render everything first, with all the passes(lighting, mat shadows, Diffuse, Reflection , etc) then Place a material overwrite with matte/shadows in everything except the people and render only the people with their passes too and then mix in post.

 

This get tricky if there is glass and reflections, and shadows. so pretty much always tricky in that case you may need to build your whole scene from passes instead of just pasting the people on top of your beauty pass.

 

Of course depending of your scene this may be a little simpler, for instance if there is not mixing of hard shadows or reflection/ refraction in the path of people.