Subsurface scatter pass?

[LeoH]

Hey.

I just wanted to know if there is a way in keyshot to render out a pass of the SSS separate from the rest of the image?
The way that I would normally do it in other software is to have no specularity, make the diffuse 100% black, make the SSS colour white and render the image against a black background. The result would be a black image with white in the areas of the subsurface scatter. I would then use this as a layer mask in Photoshop when compositing.
Unfortunately I'm unable to do this in Keyshot as turning the diffuse to 100%black stops and scattering from coming through.
Does anyone know a possible work around for this?

Cheers,
Leo

[bdesign]

Hey Leo-

Here is a workflow to get an SSS mask. In my examples I used a Translucent (Advanced) material. Set the Surface Color to black, Subsurface Color to white, Specular to black, Environment Background Color to black. It will appear to be solid black in the viewport. Render out as an EXR (it will still appear to be solid black). Open the EXR in Photoshop, apply an Exposure Adjustment Layer, and increase the exposure to bring back the SSS information. Finally, desaturate the image. The example images below are:

1. Raw beauty render
2. SSS mask (after Exposure Adjustment Layer)
3. SSS mask applied to a Hue/Saturation Adjustment Layer
4. SSS mask applied to a Layer Style

Hope this is helpful

Cheers,
Eric

[Esben Oxholm]

Nice tip, Eric!
Very cool. Thanks for sharing.

[bdesign]

Absolutely, Esben! Thanks very much man

Cheers,
Eric

[DMerz III]

Wow Eric, you've done it again! Nice solve!

[bdesign]

Thank you, dmerziii!