Vray Hair and Shave

[UCDenver]

We have been using the default shading for Hair with Shave and a Haircut. It is really slow. How can we speed this up?
Also, how do you attache the Vray Hair shader to Shave?

Thanks,
Steve

[Morbid Angel]

For the first question there is no real way to speed up hair with a raytracer. I would recommend limiting your lighting to point/directional lights, do not use dome light, that slows down the rendering quite a bit. Area lights are ok, but they are also soft shadow casters, keeping them to a few in the scene can be manageable.

[UCDenver]

I have seen another raytracer (Arnold) crank through hair and wanted to know what I could do to make Vray a bit more competitive with it. If you do not raytrace through the hair, how do you get it to shadow and self shadow. Mental Ray's hair rendeing is pretty fast as well but I believe they are depth maps.

[Morbid Angel]

I have done some extensive speed comparisons between vray and arnold. They are nearly identical in render speed (not hair), but general shading purposes, shadows, glossy reflections, caustics etc. Regarding hair though, I could not get shave and haircut to work with arnold, so I can't test it but Im certain that any raytracing of hair would be slow, hance the use of shadow maps/depth maps etc.

[vlado]

Also, how do you attache the Vray Hair shader to Shave?

This won't work for the time being; it requires changes to the Shave plugin for V-Ray. In any case, we are looking into ways to speed hair rendering and there are a few things coming soon.

Best regards,
Vlado

[UCDenver]

As we have here. I find the ability to use brute force and light cache and skylight portals for interiors is FAR faster in Vray. Hence the reason we would like to get hair working better. i switched the lights to dmaps and left the environment dome. I tried hair without brute force light cache and used IR map and Light cache and we are head to head with arnold and hair in render times and it looks far softer and more realistic in vray. The issue then is using brute force which we often times find we need with our dimly lit interiors. Though Arnold brute forcing an interior becomes a bear to render with respect to time as we have to through tons of rays into it to get the grain out. Why brute force for vray? Noisy ir maps with animated characters and lights. Not interested in pre-computing IR maps.

[vlado]

Yes, I understand the point... the V-Ray hair shader would help with hair render times quite a bit, if only it worked with Shave I'll bug Joe about it a bit more...

Best regards,
Vlado

[Morbid Angel]

how deeply does the character interact with interior? could you split the scene into two layers, i.e. interior/character. You may benefit from optimizing the lighting for the character quite a bit.

[hellobard]

maybe you should give Peregrine Lab's Yeti a try? it works just great with the VrayHairMtl's and it all renders quite fast. Easy to setup and use.

[UCDenver]

That is really a shame to hear. We are subject to the American blockage thanks to Joe Alter. I guess we have to wait to see what Vlado can get Joe to do in getting Vray Hair applied.

[vlado]

I guess we have to wait to see what Vlado can get Joe to do in getting Vray Hair applied.

Yep, working on it...

Best regards,
Vlado

[UCDenver]

Would we be able to use the Vray Hair shader in Softimage if we use something like Melena or Kristinka? Can the Vray Hair shader be applied in Softimage's version of Hair (which I know is shave & haircut). Sure would love to get out from under Alter.

[vlado]

Would we be able to use the Vray Hair shader in Softimage if we use something like Melena or Kristinka? Can the Vray Hair shader be applied in Softimage's version of Hair (which I know is shave & haircut). Sure would love to get out from under Alter.

Yes, no problem with either of these.

Best regards,
Vlado

[jpwestmas]

Joe Says to use photon mapping and you will get huge speedups with Shave for maya.

http://www.cgfeedback.com/cgfeedback...?t=1562&page=2

BTW Is Maya hair system (not shave) officially supported by Vray Maya 2012? I didn't see it in the docs?

[vlado]

Joe Says to use photon mapping and you will get huge speedups with Shave for maya.

Maybe, but I can't really recommend this method...

BTW Is Maya hair system (not shave) officially supported by Vray Maya 2012?

It is.

I didn't see it in the docs?

It is mentioned in the geometry section here: http://www.spot3d.com/vray/help/maya...a.htm#geometry

Best regards,
Vlado