I expected my rendering to look completely the same no matter what resolution. But the noise and/or reflection is way different when rendered 4x bigger for example. I resized the rendering to show the issue and put it next to the original output. Is there something wrong in the material?
Blend-file attached.
test01.blend (107.0 KB)The displacement is calculated per pixel, so the output is different if you increase the resolution.
You can try to disconnect the displacement node and put a Bump node in the Normal input of the Principled BSDF Shader, then the output is the same no matter the resolution.
Unfortunately it behaves the same with the normal input.
With detail 5 in the noise node, there is a lot more hidden detail that will reveal itself when you zoom into it - or render it bigger.
Maybe also the film pixel filter type and size and image size reduction algorithm used comes into play, I’m not sure.
Also, it doesn’t really matter if you’re using displacement or bump if displacement is faked. If you want to tweak the bump effect (through bump or fake displacement), temporarily use adaptive subdivision with microdisplacement for real displacement - that’s the only way of tuning the bump to correct values. The bump node should use strength 1 and the distance tuned waaaay down. I don’t know if it will help, but I always use this method to get sensible bump effect and also verify bump directions and relations are correct.
