Yes mapped shadows with high bias settings are going to ‘miss’ a lot of geometry; and for SSS to function properly proper shadowing is a must… raytraced shadows with a little softness and a bias of around 0.1 is a good start.
Regarding the SSS depth thing - this is how far into the substance the light is allowed to pass before it scatters, generally in CM if the shader interface is written correctly. So values around 0.1 are going to be ‘correct’ for human skin. You’ll need to reduce the shading rate for the SSS to around ‘1’ to reduce artifacting. Don’t forget to set the index of refraction to 1.3 or so.
I’ve recently been experimenting with the UberShader2 and had some good results with the SSS engine there.
Check the commentary on this image from my rendo gallery for specifics:
Wow, can’t believe this is my first post to the “new” forums, been away for a while!
Great info Michael.
Michael. Yes thinking about the measurement increments in Daz Studio 1 being 1CM then a SSS scale of 0.1 makes sense I will have to try that.
The SSS Group setting is for when you have different SSS settings for different parts of the same object. Example I apply SSS to the Sclera, Skin, Teeth etc so I give the Skin a group number say 0 and then Teeth Group 1 and Sclera group 2 and so on. This is so 3Delight knows that different parts have different SSS properties. Without this grouping 3Delight would lump all SSS together as one when calculating.
As for getting a good balance between the colours burnt in to the textures and choosing what colour SSS to have is a matter of trial and error. But starting at a red colour for SSS and adjusting the diffuse has worked for me so far. I found, with using my limited library of older textures that I have in my library, I am choosing a very saturated colour with very little red in for the diffuse colour.
I am just starting to really get some tests going with this and to be honest it a going to take a while to get a grip on what does what and why. To be honest depending on what you want and the look you want there is no right or wrong way to do all this. I don’t use Ambient, I get lights to do that part, some love ambient that is there choice and there make some nice artwork with it too. So who am I to judge or tell anyone what is the right way. But I will say if you want realism then yes I do think there is a more defined path.
This is Chase skin textures by Morris on M4 in DS3A. All rendered with same light set up, Ray Trace Shadow Key Distant light. Two Fill light - Uber Spot two Back Rim lights - Uber Spots, One Bounce - Uber Spot Uber Environment 25% No HDRI Map just using the colour channel set to Occlusion with Soft Shadows. All the spots apart from bounce set to Deep Shadow Maps with 25% soft shadows. All lights white apart from the Uber Environment a mid blue. Oh yes all lights that have shadows, bias set to 0.10
Before: Loaded the skin maps and rendered, granted the lights were set up for the Uber Surfaces mats so it isn’t a fair comparison but it does illustrate the change.
1: My first attempt with adjusting the diffuse colour, reducing the red channel only.
No ambient in sight here
Spec colour white
Velvet a peach/brown 20% Strength at 15% Fall off.
100% strength with Interjection SSS maps loaded
SSS Colour 128, 0, 0
SSS Samples 128
2 Same as above with just changing the diffuse colour only
3: Again changing the diffuse colour and turning on Spec 2 channel. Which does make him look a little sweaty granted but these are only tests.
Oh and yes I know the eyes look weird in image 1 as I was playing about with the Fresnel settings but I think they look much better in image 3.