Skin and Subsurface

With 4.6 and the SubSurface profile there has been an effort to improve skin rendering.
We’re currently looking at the artistic improvements of this system but I have some further questions:

-Back-Scattering is not yet added to the SS SSS I believe. Is there a timeframe for when this will be available?

In an answer to another question Martin posted some interesting numbers regarding performance.

-Do you have any numbers relative to the other (old) method of doing SubSurface? Is SubsurfaceProfile faster, slower, by how much?

Thanks.

-Back-Scattering is not yet added to the SS SSS I believe. Is there a timeframe for when this will be available?

Sorry - no date yet. We constantly improve our features (e.g. SubSurfaceProfile now looks less half resolution, SubSurfaceProfile Metallic support to blend with other materials) but we have many things to juggle. It’s on the list of this to do.

you have any numbers relative to the other (old) method of doing SubSurface? Is SubsurfaceProfile faster, slower, by how much?

I measured it on some platform that I don’t want to share the numbers. Since then multiple changes went to the code so the number have changed again. If you really care you setup a test to do that yourself.
The different methods have vastly different methods and performance and quality characteristics. A comparison is hard. If all goes well we hope to replace the old method with SubsurfaceProfile but first we need at least back scattering. Look will change as the old methods are not energy conserving and we want to fix that.

Hi,

We think this post contains useful information which we would like to share with our public UE4 community. With your approval, we would like to make a copy of this post on the public AnswerHub which includes the discussion but strips out your username and company name. Please let us know if you are okay with this.

Thanks!

Hi Martin,

Thank you for the in-depth answer.

Could you elaborate on: “SubSurfaceProfile Metallic support to blend with other materials”.

Does that mean the Metallic and SubSurface profile inputs can both be used in the same material?

For the performance, I understand it’s a difficult thing to answer. I guess I will hold off on testing that until some more changes have been made.

Thanks.

Does that mean the Metallic and SubSurface profile inputs can both be used in the same material?

Yes, but that is in latest main (perforce) - I don’t think it’s in the the released version.

I also had trouble through finding it.

I made the change on:2014/12/17 but I haven’t seen the change in 4.7. So it should be in the next release.

Ah, that is very interesting. I will keep an eye on the release notes then :wink:

Thanks.

Hi Martin,

Is there any progress on this?

Metallic is support on SubsurfaceProfile for a while now - now sure in which release it made it to - you can browse the Release Notes.

Hi Martin,

I’ve checked the release notes for 4.5, 4.6 and 4.7 but there is no mention of Metallic support for SubSurface.
We are currently working with 4.6 and when using SubSurfaceProfile the Metallic pin is white and available on the main material node but there is no output when you view the Metallic buffer.
In the 4.6 source code it’s clear that the metallic and opacity buffers are mutually exclusive when SubSurface is used.

The documentation about SubSurfaceProfile also says that Metallic is not supported.

Edit: I checked in 4.7 and now the Metallic pin is greyed out and not available when the shading model is SubSurfaceProfile.

Thanks,

Sure, go right ahead.