Vray SSS Render Element with Diffuse

[emrau]

Hi again

 

I would like to render an object that has SSS. I have a diffuse map and sub surface map plugged in and my diffuse amount is set to 0.

 

But when I render my passes, my diffuse and lighting are black and my SSS pass is full, obviously because I set diffuse to 0.

 

So I set diffuse to 1 which makes the diffuse and lighting pass normal, but the SSS is now black.

 

I don't want to set the number anywhere in between 0 and 1 because then either the diffuse or SSS will not be showing it's true 100% value.

 

So my question is, how can I render a full value SSS pass while not affecting any of my other passes?

 

Thanks!

[Chris MacDonald]

I don't want to set the number anywhere in between 0 and 1 because then either the diffuse or SSS will not be showing it's true 100% value.

 

You have to use a mix, otherwise the object you're rendering will break the first law of thermodynamics. Vray will internally calculate any maths, you just need to create the material so that it looks right.

 

An object in real life doesn't have both 100% diffuse AND 100% SSS. A percentage of light will be reflected diffusely, a percentage will be reflected specularly, and a percentage will be absorbed, bounced around and then either end within the material (changing its energy to heat) or bounce back out.

 

All of these can never total more than 100%.

[emrau]

Thanks for the reply.

 

I fully understand what you are saying and already knew that, but I still want both passes at 100% for compositing in Nuke.

 

I could just render it out twice, but I am trying to get both passes in 1 render.

[Chris MacDonald]

create render elements for them both.

 

Try setting the effect to 50%, then adjusting levels etc in post?

[emrau]

I tried setting the effect to 50%, but I feel that's more of a compromise than a solution, because I won't be getting a true diffuse and SSS pass.