Material Blend modes & questions regarding IOR

Tue Feb 19, 2013 12:45 am

Sorry I'm posting a lot lately and asking questions. I'm experimenting with skin shaders and SSS these days. What I realized was that the way the material mix works is based on an opacity and there is no blending modes available to my knowledge. What if I only want the reflections/specular from the glossy material? I'm asking this because when I try to blend a glossy and a diffuse SSS, I either don't get enough SSS or I don't get enough specular. I got around this by increasing the scale of the SSS and the absorption/scattering. However as soon as there is a back light the entire head mesh starts to glow. So I was wondering if someone could shed some light on this topic, it would be nice if we could isolate the specular like when you use a "screen" blending mode in mentalray or vray

Secondly, I don't quite understand the IOR. The standard number for skin is 1.33 and whenever I punch that number in the fresnel effect seems to remove the specular completely. This makes it even harder to blend materials because the specular/reflection is so minimal that as soon as you blend the 2 materials together it practically is non existent which makes me think that a blending mode would be nice to have.

Additionally, whenever I use a map to drive the roughness I don't seem to get as much range as a slider would. When I want something to be really glossy I would pretty much put pure white in the map (I turn on the invert, cuz it makes more sense for my brain to wrap around it since that's how glossiness maps work in mental ray and vray) but I would never get those nice sharp reflections like you would when you turn the slider all the way down.

Thanks again for any help that anyone can offer!

Tue Feb 19, 2013 4:13 am

Image textures have the same range as sliders. Make sure you set the power slider to 1.0 and you may have to tweak the gamma slider.

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Roelaned

Wed Feb 20, 2013 5:29 am

thanks for the response! I got it working after a while. It was the mix material that was blocking out the specularity a bit so I couldn't get the full extent of it.

What about blending modes? Anyone managed to find a way to have it working? Or do I have to do it in post process?

Thanks again