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.
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.
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
I understand your confusion. Blender developers have really done and are doing a lot of good for the development of this product, but sometimes they surprise with their ridiculous decisions where everything worked fine. Putting parameters in expanders was also a stupid decision in my opinion, and here is a topic where people also talk about it. In short, the new UI for the Principled shader in Blender 4.2 is not user-friendly. I also noticed that in terms of response 4.2 has become noticeably slower compared to 3.6.5
I disagree. As more and more features, most of which that are not going to be used for most materials, being able to collapse into panels makes the node view cleaner.
Also, “worked fine” despite all the reports that it didn’t? Sheen was a hack, failed furnace test (energy conservation, including boosting energy), GGX Multiscatter produced too much noise, coat was simply added, coat GTR (prettier for coat than GGX due to its longer tail) distribution was broken (now GGX), no way to setup IOR relation between substrate and coat IOR.
The whole point of Principled is to be an easy way to setup plausible materials. If OP wants to make “unrealistic and physically incorrect materials for artistic purposes”, then Principled isn’t the way to go. Also it’s not the way to go if you want to do something that isn’t supported - at least yet.
Glass shader could be better, but it’s also one of the easiest one to replicate; fresnel to mix between refraction and glossy shaders. That allows individual colors, roughness, and even normals which is a requirement for doing frosty glass for thin geometry glass; use Geometry/Incoming normal for refraction shader only. Personally I mix diffuse and translucency as well, which is then mixed with refraction, which finally is mixed using fresnel with glossy.
