Hair rnd by strand

V-Ray V-Ray for Maya General
1

Heya,

I am somehow too stupid to use the rnd by strand feature.

Anyone who can help me out?

Thanks Paul

2

In the latest nightly builds, the VRayHairSampler texture has a “random by strand index” output that you can use to drive a ramp, for example.

Best regards,
Vlado

3

Heya,

I have the nightly from yesterday. Do I need to upgrade?
And into which connection of the ramp should I connect the output? uCoord?

Paul

4

Hi,

The nightly from yesterday is good for the random by strand output. If you’re using a Uramp connect to uCoord, for vRamp - vCoord. Hope that helps.

5

Hm, not working. I try to use it with VRay fur, maybe this is the problem?

6

Ah, that’s probably it. It works for Yeti and Maya hair, but not for VRayFur yet. For VRayFur, you can try using a fine noise map to color the strands.

Best regards,
Vlado

7

Okay, sure noise works too :slight_smile: Thanks for the info.

8

I can’t get random by strand to work with Shave Display through a ramp shader. Is this a known issue? When I hook up the random by strand feature (in the hair filter) to a vramp I just get a single color even though there are 2 or more colors in the ramp. This is even visible in the hypershade preview icons.

9

I’m not sure it works for S&H either; I will have to check.

Best regards,
Vlado

10

Thanks Vlado, what’s interesting to me is that a B&W Vramp works fine with defining distance along strand and then plugging that into transparency. So I guess there is some kind of limitation centered around random colors for some reason. I’m essentially attempting to get more of a salt-pepper variation in the hair colors to express age, dirt or color highlights.

11

Why don’t you use the Shave & Haircut controls for that (mutant color or something), and then just set VRayHairInfoTex to use the Hair&Fur color?

Best regards,
Vlado

12

Because I didn’t know about it or how it could be used with Shave. :slight_smile: I’ll give that a try.

13

I can’t find any info on its whereabouts. Is this VrayHairInfoTex a node by itself or is it a connection part of another node?

14

It’s basically the hairSampler node in the utilities section of the hypershade.

15

So what everybody is saying is: just Connect the “out color” or “hair color” output (of the hairSampler) to the overall color of the Vray Hair material? Which in turn uses the color settings from shave.

yes, that does work, but like I mentioned somewhere else, it does render 30% slower then. I guess that’s to be expected.

16

It’s odd that it renders slower. Does it do that even if the colors are still the same?

Best regards,
Vlado

17

Interesting: At a resolution of 500px

-) shaveHairShape (hairColor connected to overallColor) Colors/ Same color value in all shave slots: 6m 38sec

-) shaveHairShape (hairColor connected to overallColor) Colors/ Multiple color values between shave slots: 5m 51sec

-) remapColor/gammaCorrect node (connected to overallColor) single color node: 4m 59sec

18

Can you provide example scenes about these tests ?

19

Hi thanks for your attention. I sent a scene to support with a link to this thread.

20

Were you guys able to see longer render times with the shave colors being plugged into the overall color of VRHairMtl? Just want to know if I made a mistake somewhere and if there is a different way to get color streaking in the hair using Shave.