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Author Topic: Vray GI flickering with Forest Color  (Read 1222 times)

vklein

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Vray GI flickering with Forest Color
« on: January 05, 2015, 05:24:28 PM »
I'm getting flickering on the trunk of standard HQ Plants with Vray materials and ForestColor applied to the leaves (not the trunk itself).
Settings exaggerated, simple test scene with preview settings.
It looks like buckets renders differently.
Network-render problem only (over beckburner).
See the attached pics, they are out of a sequence, all frames flickering at the same amount.
Seems to get worse on machines with more cores.

FP 4.33
3dsmax 2014 latest updates, Vray 3.10.02


iToo

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Re: Vray GI flickering with Forest Color
« Reply #1 on: January 06, 2015, 09:47:42 AM »
I'm comparing the images using A/B tool included with V-Ray frame buffer, and it seems there are differences with trunks as well (see attached image).

Please, would you try converting Forest to stand-alone objects using Forest Tools, and removing Forest Color ? Just to be sure the problem is caused by Forest or not.
Carlos Quintero
iToo Software

vklein

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Re: Vray GI flickering with Forest Color
« Reply #2 on: January 06, 2015, 11:36:15 AM »
Like I said the problems are mostly on the trunks.
Same scene with Forest without ForestColor works fine.
Also converted to real instances without ForestColor work well.
It's what the GI-rays hit on a per bucket basis that changes every bucket/frame.
Perhaps ForestColor not consistent randomized on the items outside the viewing cone? (outside the particular buckets viewing-cone)?

Problems occur when rendering frame ranges, not on single frames. Locally and on the render-farm.
I mean single frames render correctly, with consistent lightning over the bucket-edges.
Here is the scene (3dsmax 2014):

https://www.dropbox.com/s/ncjmbowdlo18wk9/Testscene.max?dl=0


Attached a 50 frames movie of the scene rendered on the render-farm to ease up debugging.

iToo

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Re: Vray GI flickering with Forest Color
« Reply #3 on: January 06, 2015, 12:27:23 PM »
Sorry, i didn't read well your post. I though the problem was on the leaves, not on the trunks.

I can reproduce it here, even without Forest Color. The flickering is caused by the Normal Bump map, which is not supported in V-Ray for instanced objects (as Forest or proxies).
Just replace it with a VrayNormalMap. That should solve the problem.
Carlos Quintero
iToo Software

vklein

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Re: Vray GI flickering with Forest Color
« Reply #4 on: January 06, 2015, 12:50:15 PM »
Thanks a lot.
Didn't know about Vray's problem with NormalMap, and I don't expect it to be a material problem with a default enclosed plant.
Strange thing is that I also run a test without ForestColor onto my renderfarm and the frames were OK. I used only equal machines for this test, this seamed to work somehow.
Please built a NormalMap to VrayNormalmap function into your MaterialOptimizer script to eliminate this source of trouble.
I used your default HQPlants for this test, please also clean the enclosed plants's VRay Materials from the default Normalmap.




iToo

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Re: Vray GI flickering with Forest Color
« Reply #5 on: January 06, 2015, 01:54:11 PM »
This is a known problem in the recent releases of V-Ray, but i'm not sure if it happened also in previous versions (V-Ray 2 and before). This may be the cause that HQ Plants uses Normal Bump instead VrayNormalMap in their materials.
We'll inform to 3D Mentor about the problem, so they update their libraries. Unfortunately we cannot make changes on third-party products.

Thanks for you suggestion about Material Optimizer. We'll add this functionality in next updates.

I could reproduce the error rendering locally, removing Forest Color and selecting a frame range. Rendering a single fine works fine.
But the behaviour would be different in your render farm. If the problem is not fixed using VrayNormalMap, please tell us (in case there is a different problem).
Anyway, elements which don't use Forest Color (as trunks) are rendered directly by V-Ray. Forest should not affect in any way, because doesn't participate in the render process.

Apologies by the incoveniences.
Carlos Quintero
iToo Software