Good evening. I’ve been working on some updates for my advanced skin shader and during some of my tests with Global illumination (which is set to baked), I notice that even in areas of shadow, transmission shows up at full strength.
The shader is created with Amplify Shader Editor and I’m wondering if this happens because of the lack of raytracing (I’m currently using an old laptop with an ancient GTX 670M) or will I need to do something more in the shader side… maybe I can use fresnel on the transmission and make it’s intensity view dependant (I work with offline renderers and I’m expecting the head to self shadow.
I don’t have a direct answer unfortunately, however it’s worth debugging your AS node graph with any lighting contributions to the transmission & thickness maps you may be using.
If this is just ambient light causing this, it may be additive from within the mesh itself ( depending on two sided or not) essentially there should be the absolute minimum of SSS going on in a scene that is overcast or neutral with minimal direct lighting.
Scene lighting as a whole can also massively affect this, so ensure you have a well balanced scene, if you’re purposely breaking PBR you would also have to adjust SSS too.
This is because you can exposure a scene to look the same but have wildly different EVs.
Like a day scene @ 100k lux 14EV, Vs a day scene @10k lux EV10.5
once your break PBR, everything that is affected by light would also have to be adjusted accordingly.
You could potentially debug a little further maybe in screen space as well. It won’t be as accurate but it may give you some faster iterations whilst debugging/updating shaders and lighting
Honestly, it’s just the texture plugged into the thickness input with no modifications whatsoever. The test scene also has an HDR map with it’s exposure set to 13 (shouldn’t the texture just show up without doing any of this?) and the whole glowing ears still happens even with no lights enabled.
The best I can do is just adjust the amount of transmission
Here is a shot of my LookDev scene. The ears are still glowing even with no lights in the scene. Maybe lowering the exposure of the skybox might alleviate this, or some other tweaks, but it will leave my scene a bit dark. In the old Unity days, I could just plug this HDR into a cubemap sky and it would just behave
I just found by accident that on the Volume / Shadows settings (where you set the shadow cascades for directional light) a transmission multiplier slider. Never saw this before, but it reduces the transmission in shadows if turned down. Not sure if it helps in your case.
I didn’t notice this. I’ll have a look when I get home. I was also able to stop the transmission from showing up in HDR sky environments by increasing the transmission distance in the diffusion profile
