Blotchy flickering on VRay Fur between frames - not GI

[Dynedain]

I'm having problems with


Here is a slow-motion example of what's happening:
http://www.kaadesigngroup.com/temp/blotchgrass.mov (400k)


As you can see, the grass (VRay Fur) is getting blotchy patches. I've already ruled out it bing a GI problem, as GI is turned off in this render example. Modifying AntiAliasing settings also seems to have no effect.

The only thing that I can figure is that the UVW map that is applied to the underlying object is being ignored. The only map involved is a simple bitmap applied in the diffuse slot. The underlying object has a planar UVW map.


Can anyone figure this out?

[Dynedain]

I've tried applying a uniform diffuse color (instead of a map) and can verify that the flickering goes away.

In other words, this means that the VRay Fur is having a problem with UVW mapping...

[LarsSonparsson]

Thank you!

I'm having that same problem, but didn't had time to
find the reason for it. For my project solid color will be fine.

Anyway, this really should be fixed!

Max 9 64
V-Ray rc4 64


-LarsSon

[jacksc02]

vrayfur works perfectly well with uvw mapping in RC4.
You just have to becareful with the W co-ordinates

[Dynedain]

I don't have any W coordinates, as I mentioned, it's a planar UVW map on the underlying object. And as you can see from the animation sample, there's substantial per-frame flickering.

I'm on RC4h

[DaForce]

For curiousity sakes, just chuck a Box uvw map on that sucker. I probably because of the lack of W mapping thats causing the problem.
Any errors in the vray log?

[Dynedain]

I had tried that, and got the same results

[jacksc02]

any chance you could send me part of the scene?

PM me

[Dynedain]

Done, and I added you on MSN

[Dynedain]

So jacksc02 has been very helpful in taking a look at the scene and helping me brainstorm the problem, but together we still haven't been able to identify a solution.

Here's what we've tried:

• GI - Example clip has no GI
  AA - Tried different Anti-Aliasing settings, including turning AA off, QMC, and Adaptive Subdivision. Problem occurs regardless
  UVW - Tried switching to box-model UVW on base object, no change. Example has simply a basic bitmap for diffuse, no procedurals (although the problem happened with procedurals as well.
  Dome Light - Turned off dome light, problem still occurs.

There's only two things left I can think of to try... and I'll run them through today... but this is looking more and more like a bug with the UVW mapping on VRay Fur.

[vlado]

If you wish, you can send me (a part of) the scene to vlado@chaosgroup.com for investigation - if it is a bug, it must be corrected.

Best regards,
Vlado

[Dynedain]

Thanks for offering to take a look vlado, here's an update.

I tried removing all environment lighting/maps - still have the problem. Only one thing left that I can think of...

[Dynedain]

One more update...

I tried turning off every source of lighting in the scene (environment, lights, etc) so that there was only 1 direct light, with no shadows, no GI....

Problem still exists.


I am officially out of ideas.

[DaForce]

Send it to Vlado

[Dynedain]

Already did... just posting here for the record in case other people run into the same situation... and to let Vlado know what i've tried.