Overbright in motion blur - Fur

[Resin]

I am getting clamped over bright colors in motion blur frames. Does anyone know why this happens? Its happening on shave hair cut fur.

[vlado]

You are getting a warning about this, or simply the colors get clamped? What are your color mapping settings?

Best regards,
Vlado

[Resin]

I am getting over bright white colors and im getting little black spots.. My settings under color mapping are

Type: Linear multiply
Gamma 2.2
dont affect colors (adaption only)
liner workflow

[pechart]

Is it a problem? Do you render to EXR 32bit? Then everything should be fine.
Only problem then is, if you have very hard contrasts (maybe from 0.3 to 120 float). You'll get bad antialiased edges then. This can be "corrected" by using the clampin value in the rendersettings to clamp the colorvalues to more "antialiasable" ranges (like 0-5).

EDIT: Or did i misunderstand the question and the overbrights should be there but are clamped in the float image?

[Resin]

The over brights are a problem and is not fixed by rendering 3dbit / 16 / 8. It happens regardless of output type. The fur starts to "glow" under fast movement even if there is only one very dim light in the scene. Its looks very strange and I think its something that cant be fixed via render settings but more of a BUG. It looks like the colors multiply on top of themselves regardless of light levels. Antialising is pretty important for us too because there is a high level of motion blur. 2D blur is not an option for us either. HELP!!!

[vlado]

Ok then, would it be possible to get me a scene with the problem to vlado@chaosgroup.com (I can't seem to be able to reproduce it here)?

Best regards,
Vlado

[Resin]

Sure Vlado i will get you a scene today, I did a render a few nights ago (i have been away sick for a few days) and it turns out that the overbright issue is actually creating light!! I have fur interacting with fluid effects and the over bright is creating light on the fluid!! makes dust look like fire!! soo crazy..

[Resin]

I have a worked out how to get a slightly better result but its not fixed the issue. Using the adaptive method not the DMC is better but now I get little black holes ripping through the motion blur!!! grr im going around in circles. Also I get alot of V-Ray warning: Invalid geometric normal (0 -1.91063e-014 2.2593e-013) for "shaveVrayShadeable". Dont get that error when im grooming a static character, its only under animation.

Is shave hair cut simply not developed for Vray correctly?? HELP HELP HELP!!!

[vlado]

This looks to be a problem with the Shave plugin, so it would be best to contact Joe Alter and get him a copy of the scene.

Best regards,
Vlado

[Resin]

Ok so looks like the new shave haircut shader has fixed the over bright problem! yay... however, when motion blur is turned on I get "V-Ray warning: Invalid geometric normal (-2.2004e-013 7.05371e-013 3.96383e-013) for "shaveVrayShadeable"." for what looks like every hair on the characters!! ahhhh >( plus it renders very very slow. Mental ray is a whole lot faster to render the same thing and probably looks better because I can have tip fade turned on. Is there some special render setting i'm missing? I have tried lots of alternative AA filters + GI methods with not a whole lot of luck. My MR time for 1.5Mill Hairs with tip fade and MB is about 15mins whils vray is up around 1 hour +. grrr the never ending saga that is rendering fur...

[vlado]

It's so slow because of the warnings that are printed. Can you get me a file where I can reproduce them? I don't get them in the scene that I have.

Best regards,
Vlado