VrayMaterialHair3 results are dark...

[evanerichards]

I've been doing some fur tests with the vraymaterialhair 3. I've been finding that the results are really really dark.



You can see from the picture how much brighter I had to make the image just to lighten the hair. But by the time the hair starts to reach a reasonable lightness the other parts of the model are completely blown out. The color on the top there is supposed to be bright hunter orange.

Any ideas why that may be the case?
I'm lighting with a dome light mapped with an HDRI.

[vlado]

What are the settings of the hair material? Do you have GI enabled?

Best regards,
Vlado

[evanerichards]

Gi is enabled.

The settings are:
Overall color and primary secular are mapped with colors from a jpg.
Diffuse Color = black
Diffuse amount = 1
Primary Glossiness = 0
Secondary Diffuse locked to first
Transmission = Black
Transmission amount = 1
Simply for GI = On
Cached for GI = On

No matter what my GI settings are the shader is still super dark.
Also is the vraymaterialhair 3 supposed to render anything on a diffuse render element? When I render out a diffuse pass I feel like it should be flourescent orange (since that is what the fur color is) but it is almost completely black. The image is still dark btw if I manually change the color of the fur to fluorescent orange vs. mapping a color from an image.

[vlado]

You will need to either add some diffuse component, or some transmission component (or both). If you just use the primary specular, then the result will indeed be a bit dark. Since the diffuse color of the shader is black, this is why you get a black diffuse render element.

Best regards,
Vlado

[evanerichards]

Hmmm. That is strange. I've been doing a lot of tests and when I changed the transmission color to white the render actually got darker rather than lighter.
I hadn't tried the diffuse because I had read "Note that clean hair or fur does not normally have a diffuse component, so in that case leave the parameter black." Now that was from the 3dsMax vray manual but I assumed perhaps wrongly that it would be the same in Maya.
I'll give it a test and see what happens. Thanks

[evanerichards]

Yeah. That actually made things a little darker.
Here's the reference.

[vlado]

Hm, the diffuse component will take away from the other components so that the shader is still energy preserving. It's odd though, that the rest of the scene is so much brighter. Can you post just that part of the scene or send it to us at vraymaya@chaosgroup.com ?

Best regards,
Vlado

[evanerichards]

I wish I could. It's kind of a proprietary hair system so you wouldn't see the fur on your end. I'm trying to see if I can duplicate it with the vray fur. Will let you know.

[t.petrov]

Have you looked at the vrscene file?
If the hair is exported as GeomMayaHair, sending the vrscene will be enough, probably.