Brute force + light cache - flicker

[redhafauzi]

Hi I did an animation test to study brute force. There's a slight flickering occurred at the bottom of one of the white pots circled in the image below.

 

 

Here's the render setting

 

 

Here's the summary

 

AA - Adaptive DMC (Area - size 1.5)

Min - 1

Max - 100

 

GI

Primary - Brute Force, Subdv 64

2ndary - Light Cache, Subdv 2000, Sample Size 0.02

 

DMC Sampler

Noise Threshold: 0.002, Adaptive amount 1.0, Time dependant

 

Rendered at 1920x1080

 

Here's the image sequence. Try and download the images into your local hard disc and play the animation to see the flickering.

 

 

Is the render time too long for an animation? the ceiling is set to glossy reflection with ward material. For the purpose of the test, every single object in this image is glossy with blurred reflection. Thank you

[redhafauzi]

Owh yah, I for got to inform. Subdivision values for all materials and lightings are set to default. reflection depth are within 3 - 5 depending on each material. These are settings i get from chaos group's own BF Universal Setup.

[Francisco Penaloza]

Rendering with Brute force will always imply longer rendering time, if you have the computer power and objects, lights and camera are moving, this is the way to go, now if nothing is moving, besides the camera irradiance should be used, Time Vs quality there is no way around.

Now for study purpose, you should not apply universal method for animations, universal method is one old attempt to "one setup fits all" sort of thing, and it will take longer than really need it. This is not optimized!

Just after a quick look at your values I can tell that your DMC is way to high and you Brute force samples are too low, as well your materials samples. If you are using VRay 3 this can be fixed with the shader sampler but in VRay 2.x this had to be controlled manually on each material.

Long History short.

Read this, and it will help you to find your sweet spot rendering speed/quality

Fco.

[redhafauzi]

Thanx Francisco Penaloza, I'm reading it right now =)

*the haze in Kuala Lumpur this morning is like shallow z-depth, glad it's raining.

[Zdravko Barisic]

http://www.workshop.mintviz.com/tutorials/flicker-free-animation-using-vray/

 

 

http://www.cbuelter.de/

Edited March 4, 2014 by okmijun

[thanulee]

I have exactly the same problem, though my samples are very well optimized and really high. What is the problem with the brute force solution in animations? the same scene with im+lc prepass method, worked like a charm in terms of flickering, while in terms of detail in small areas brute force is the best.

Should i have both primary and secondary as BF?

Should i have only my primary engine on as BF?

Should i increase more the samples (i doubt that this is the way)?

thanks

[Francisco Penaloza]

Thanos,

Brute force should not produce flickering, it only produces noise, less sample more noise, more sample cleaner image.

If you image looks like blotches of dark and bright, the problem is Light cache map, check those values, for animations fly though mode and save it, then read from file.

 

You could also let the light cache be calculated for each frame, but this generate more noise.

 

Also it is recommended to use world scale no screen. In some extreme cases BF-BF is the only solutions but this is only if everything is moving.

[thanulee]

Ye i believe that light cache causes the issue too. Its not a camera flythrough though, i got all kinds of animations from camera movements to transforming/moving objects etc.

 

How should i set up light cache then? Leave it as secondary bounces? Flythrough mode there?

How about using bf as secondary bounces also will it help? Render times will be massive?

 

Save me dear friend thanks a mil

[Francisco Penaloza]

if your object are moving or changing shape, you should not bake your GI.

You can try to still using Light cache as secondary but let is calculate for each frame. If still to noisy, then just put BF in both primary and secondary and bite the bullet with the time, there is no way around.

 

Well actually there is a way around. not using GI, you can setup a nice light rig and fake light bouncing and all that, just like old school and forget about GI, just like big studios

 

V Ray dome light can be a great help here.

[thanulee]

"You can try to still using Light cache as secondary but let is calculate for each frame."

And how i do that?

I untick store direct light and tick camera path?

 

Also no matter what i ll do at the end u believe using vraydome for skylight is better than just adding a color to the environment?

It will be a night scene so i just need a dark blueish for gi no maps there.

thanks buddy!

[Francisco Penaloza]

for light cache just leave it as default, Single frame mode. It will take longer per frame, but it can work.

What type of animation are you trying to do?

V-Ray sky dome it is a light, using a color in the environment will not produce any light, if you turn of GI.

Even at night you have light coming from the Moon, or lamps around you and such. so there is always something illuminating your scene, unless you are in a room with no lights.

[thanulee]

I will have a town in a night scene with mostly neon lights. How would u set that up?

(in an older similar project i had 1 sphere light representing the moon at very low intensity and a dome light for GI.)

[Francisco Penaloza]

Well I would need more information to tell you what I would do, also without being arrogant, but my workflow may be more complex than you are used to do. Maybe I will render the set and use it as backdrop in a 2.5D comp in fusion, or render everything in passes and comp in Fusion or After Effects. I can use GI in the environment and set, and Brute force in the moving objects.

 

Usually for Arch Viz, this workflow is way to much, that's why we are comfortable using GI because, if anything moves, still be be GI - baked.

Maybe for your scene the best solution can be, use Irradiance and Light cache, but use detail enhancement on Irr, this way, Brute force rays will be shoot in the complex areas to not lose detail that only Brute force can show. Or a very high Irr setup.

[thanulee]

check this out : https://www.behance.net/gallery/14550547/BE-NOISE

 

Im making something very similar, i work like u do almost, but this time i wanna try brute force into the workflow (if possible)!

[Francisco Penaloza]

Well for what I saw some area lights with dome light will do just fine. Maybe an ambien light to give a little color bounce to the whole scene too.

 

GI what it does in your case is help you to simplify you light rig. I will give a try BF/LC and see how it goes, let it calculate each frame, just as default values. if not use BF both bounces.

If you are using V -Ray 3 your rendering time won't be as bad as with V_Ray 2.x

You can also try Corona render, it is faster than V_Ray 2.x brute force and maybe faster than V_Ray3 with I don't have it so hard to compare, but considering the setup time, Corona can give you great result faster.

[thanulee]

Ye im trying now a test render with bf + bf and seems flawless from 15 frames im checking.

 

Btw although environemnt color gave same GI result as with dome light, in light pass only dome light appears u were right! When i set up the whole scene i all ask again thanks bud!

[Francisco Penaloza]

no problem, glade to help.

[siddharthkolte]

Hi I did an animation test to study brute force. There's a slight flickering occurred at the bottom of one of the white pots circled in the image below.

 

[ATTACH=CONFIG]50894[/ATTACH]

 

Here's the render setting

 

[ATTACH=CONFIG]50895[/ATTACH]

 

Here's the summary

 

AA - Adaptive DMC (Area - size 1.5)

Min - 1

Max - 100

 

GI

Primary - Brute Force, Subdv 64

2ndary - Light Cache, Subdv 2000, Sample Size 0.02

 

DMC Sampler

Noise Threshold: 0.002, Adaptive amount 1.0, Time dependant

 

Rendered at 1920x1080

 

Here's the image sequence. Try and download the images into your local hard disc and play the animation to see the flickering.

 

[ATTACH=CONFIG]50897[/ATTACH][ATTACH=CONFIG]50898[/ATTACH][ATTACH=CONFIG]50896[/ATTACH]

 

Is the render time too long for an animation? the ceiling is set to glossy reflection with ward material. For the purpose of the test, every single object in this image is glossy with blurred reflection. Thank you

 

Make the AA from Area to Gaussian and set the size to 3.0 or 6.0 depending on the quality. This way the the combination brute force and lightcache gives smooth results. This used to be my settings for car renderings.