while I took a look through the project settings, I found two options in the Materials section. I did not found any viable documentation and thought maybe somebody here knows more about.
The first one is “Enable Rough Diffuse Material”
The second one is “Enable Energy Conversation on Material”
The only info I found was here on the forums:
“For material to be true PBR, it has to be somewhere in real world. Otherwise, it is all just approximation. In the industry, PBR, typically means energy conservation (material cannot reflect more light, than it receives).”
Any idea on these?
PS: And why is any UE5 version tag in the title not working…
Upon further investigation the “enable rough diffuse” changes the default diffuse model to the “Chan” model used in Call of Duty: WWII and ties roughness to specular roughness.
Here’s the presentation if you want some more info on the shading model.
The “enable energy conservation on material” seems to change the fresnel in some way though I’m not sure exactly how.
Was curious about these two options as well! Here’s a before and after with both of them on. Pretty subtle, but the slight darkness shift on diffuse and fresnel adjustments are kind of nice! Reflections feel clearer particularly on the glossier floor, rubble reads nicer on top of it. The darkness I’m getting in the SSS geo leaves feels much nicer as well.
(Click on images and switch back and forth with arrow keys on keyboard for full before/after effect)
Wait, what?
Unreal’s renderer is not energy conversing by default?
Edit:
After some comparisons, it looks like it isn’t indeed.
I’d be curious why this isn’t enabled by default.
I haven’t found any performance reasons (10ms render time with or without it).
When a light source directly lights geometry it makes a huge difference, otherwise, I found it negligible.
Oh! I’ve found that option for a long time, I think this may effect the Diffuse term and Specular highlight term, by making them more brighter(In fact, I capture the process of calculation by renderdoc, find that they try to compensation the energy by adding the multi-scattering terms)
