Omni Black Hair Shine Reduction?

RexRed

Omni Black Hair Shine Reduction?

I have a point light shining up from below and notice the black man's hair truns gray instead of staying black?

I am using omni shaders on both of these figures' hair.

The black man's beard and hair have the same omni shader.

The longer I render the worse the effect gets.

This does not appear this way in the iray view only in the final render.

What omni shader parameter is making the hair respond to the light in this way?

I know how to fix shine with roughness in the old iray shaders but not omni. 

Thanks in advance for any help on this.

felis

I have never seen something like that.

But you could try to turn the glossy layer weight down.

But I would say that there must be something else in play. How strong is the point light? Does othe SBH-Omnihair behave simarly? 

RexRed

felis said:

I have never seen something like that.

But you could try to turn the glossy layer weight down.

But I would say that there must be something else in play. How strong is the point light? Does othe SBH-Omnihair behave simarly? 

I have seed this with Iray when the roughness is too low but the Omni shader is a different thing. Not sure what changes this. 

My point light is not too strong you can tell by the character's skin it is in a reasonable range of brightness. 

There is a distant light coming down through a hole in the ceiling of the environment.

Maybe the distant light is not compatable with the point light but it only seems to have a problem with the black man's hair and beard.

The white guy's hair is also an Omin shader. It seems to have problems with darker color omni settings.

The image below is what the hair looks like in the Iray viewport.

It looks fine in the viewport (see image below) but in the Iray render (above) it looks terrible.

It is hard to fix becasue I have to render the image each time to see if it is fixed because the problem does not show in the Iray viewport.

butterflyfish

I had the same problem with that particular hair. Try turning up the hair dye weight.

crosswind

First, you don't have to render it each time to check the shine effect but just select the SBH node and turn on Preview PR Hairs and set Viewport Line Tessellation Sides to >=2. (ss1)

The default loaded hair is already shining enough with proper light, IMHO... but you still can tweak the properties: IOR, as well as Roughness Root / Tip, Azimuthal Roughness Root / Tip, to make the hair not that shiny plus some subtle changes... (ss2)

To make them more glossy, increase IOR a bit and reduce Roughness accordingly, then render them with enough samples.

Another trick is: if you want them look more shiny esp. from the your angle of view, you better well tweak the postion and angle of the light source(s).