New principled BSDF in Blender 4

[Nikita_Bukoros]

I`ve been trying some of my scenes from 3.6 in Blender 4 and there was a huge disappointment that many shaders look much worse.
I know that the new BSDF is Multiple scattering GGX by default and there are no options anymore. First of all it is not possible to even compare the render result with identical parameters in both 3.6 and 4 because Multiscatter in 3.6 is completely screwed. 4 in turn, does not have the opportunity to return to GGX, and as a result of this, it is now impossible to change the transmission roughness

I absolutely don’t care about physical correctness and energy preservation, but I need flexible artistic control, especially on materials with frozen glass effects, and now I`m struggling with it in the new version.

I wonder if it is possible to at least recreate the old one with refraction/glass shaders separately, but glass and principled BSDF with full transparency never gave similar results even in an earlier versions.

Will be grateful for any advice

[picto]

May I suggest that you post at least some pictures and, better still, a test scene.

[DNorman]

@Nikita_Bukoros

it is now impossible to change the transmission roughness

Transmission now uses the general roughness, (that has changed) to do frosted glass use a coat to give the shinny surface.

Why don't they want us to make frosted glass or deep ocean materials anymore?!

Use the general roughness for the transmission and a “coat” for the shinny surface. The coat has it’s own roughness setting to get a shinny surface on top of the rough one. Cycles [Cycles] For Eevee turn on screen-space refraction in render properteis and turn on refraction in the material settings. Eevee [eeve] Another one (that is maybe more of a pain) is the subsurface scattering colour input has gone, there are workarounds but yes more complicated.

Yes you do have to redo some old materials, but they should still be possible.

Edit; sorry I posted this in the wrong thread!

Another one (that is maybe more of a pain) is the subsurface scattering colour input has gone, there are workarounds but yes more complicated.

Subsurface Scattering colour

Hi Friends… I used to be able to precisely mix in a texture for the sss colour input… now that it is gone (fix things that aren’t broken, it’s 2023 after all), what awkward work around (using many nodes, probably) do I have to add in order to achieve the same results as with this simple input? …lol Thank you kindly and Merry Xmas.

[Hadriscus]

@Nikita_Bukoros

I know that the new BSDF is Multiple scattering GGX by default and there are no options anymore.

No, multiple scattering GGX is gone. It was replaced by an approximation (albedo compensation) which is almost equally accurate but a bit faster.
cf https://developer.blender.org/docs/release_notes/4.0/cycles/

@Nikita_Bukoros

I wonder if it is possible to at least recreate the old one with refraction/glass shaders separately, but glass and principled BSDF with full transparency never gave similar results even in an earlier versions.

You can still mix bsdfs to your liking, so a combination of rough transmission and sharp reflection is still possible. I agree removing that bit of control from the principled bsdf was uncalled for, though.

[Nikita_Bukoros]

Yes, here is a fast example from my recent scene

First one is 3.6
second is 4.0 without any changes
This is not quite good example to discuss, I will prepare may be more simplified scene tomorrow already

I usually make some unrealistic and physically incorrect materials for artistic purposes and light effects, and now its harder to manually control all parameters
For example earlier I sometimes put in base color values more than 1.0, and it created interesting effects for some translucent plastics and glass, and now it is also not working for principled bsdf. This feature as well as GGX still persist in glass and refraction BSDF, but they never worked similar to principled even in earlier versions. Glass with transmission roughness 1.0 work different than the same with principled