Vray blend material question...

[evanerichards]

So I'm trying to figure out why my blend material isn't working the way I thought it would.

Let's say I have a snake. I have the textures all painted for him, but I want to put a glassy layer over him that I can control separately.
I make a blend material. I drop the snake shader into the base shader slot.
Then I make a glass shader. 100% refraction. 1.6 IOR. 100% reflection with glossiness at 100%. I drop this in the first layer and put contribution up to 100%.

I can see the glassy texture on the snake, but instead of seeing that over the snake texture, I see it over black, as if the glass shader somehow blacks out the textures underneath it. I tried toggling "affect shadows" but that didn't seem to make any difference.

Any idea why this is the case and if it's possible to get it to operate the way I thought it would?
Please advise.

Thanks!

[Joelaff]

For this type of effect try Shellac (additive) mode.

This is a setting in VrayBlend...

[chuckie7413]

The glossy layer does not have to be refractive. Just make the glossy layer fully reflective then in the blend amount apply a vrayfresnel. You can then adjust the ior which will change how reflective the top layer gets.

You do not set the blend mode to additive in my example.

Best,

Richard

[Morbid Angel]

chuckie7413 is correct. You can either do additive blend, be careful with reflection depth in that case, but usually doing single additive blend is ok. Or, you can go physically correct and use fresnel to blend. Theoretically, where reflection is strong, the diffuse is not as strong (diminished by the reflection/specular) and fresnel takes care of that exactly.