What makes some skins take much longer to render?

tcassat

Hello!

I am doing some tests with some models I own and I noticed that some skins are much more complex to render. For example, I made two renders with the default models of Genesis 8 and The Girl 8, with iray materials. Rendering time result:

Genesis 8: 2min 17s
The Girl 8: 7min 15s

Here the result:

https://imgur.com/ZrcLgZo

 

Is there anything in particular about The Girl 8 materials that makes the skin take much longer to render? What do you recommend that I modify to try to optimize render times?

Thanks.

rames44

One possibility is sub-surface scattering - that would add a lot of additional calculations for iRay, although it can greatly add to the realism of the skin. I don’t own The Girl, so I don’t know what her skin settings like like.

tcassat

rames44 said:

One possibility is sub-surface scattering - that would add a lot of additional calculations for iRay, although it can greatly add to the realism of the skin. I don’t own The Girl, so I don’t know what her skin settings like like.

Thanks.

I noticed that you can't "turn off" the SSS, but I reduced the translucency of the model's skin and the rendering dropped from over 7 minutes to 1 minute (the skin became less realistic and beautiful, however).

I believe that by decreasing translucency, I prevented the rendering process from calculating the SSS, correct? Is there any other way to try to soften this effect to get faster renders?

JonnyRay

There are so many things that can affect a skin shader, I'd have to take a look at The Girl 8's default skin to see for sure. Adjusting one parameter (like the translucency weight) without also knowing how that will affect other parts of the shader can definitely create some unwanted effects. I learned a TON about how Iray renders skin from @V3Digitime's excellent Skin Shading Essentials Tutorial.