Question: Bug or am i doing it wrong Tweet

[larsmidnatt]

So when experimenting with settings I found a good mix material with a glossy and diffuse material. The diffuse uses scattering as well as transmission. However when I use both together it causes a lot of noise.

I remember at one point there were some rumblings of a SSS bug, and I kind of assumed this was it, but maybe I'm just doing something illegal. Maybe in the realworld things don't work that way, but it makes a good result for me when it's not noisy.

Did I explain myself OK. Not at the PC to give an example. I have kept trying different ways to get the same result and haven't been able to.

[t_3]

i don't think this is something to avoid (in general); i in fact use this sort of mix myself. question would be how much noise / under what lighting conditions / after what amount of s/pix; using transmission a lot clearly brings down performance, and depending on the amount and balance of light sources it might need some 4-8000 s/pix to get a perfect clean image, maybe even more for indoor scenes...

[larsmidnatt]

I should probably have said that it was blue dots as well. Lots of blue dots.

Thats for confirming that it's an OK way to go. I've done it before, but couldn't figure out what was different this time.

There was plenty of light in the scene, using HDR and 2 mesh lights. Not a ton of shadow, and the shaded area was actually well lit if that makes sense. I was letting it render to 8k and had a lot of blue noise. I usually only go to about 2k, so waiting that long and still having noise was a bit confusing. I've done the same kind of material before and had a small amount of noise that I could clean up reasonably quickly.

I did some experimenting and found an OK close enough setup that looks good enough and doesn't cause the blue dots. Basically I made scattering node black instead of red and changed the transmission color to compensate for the lack of color scattering.

I wouldn't think black scattering could do anything, but it does and I'm ok with that. Black scattering is very different than having the scattering at NONE/null. I learn everyday

EDIT: I was wrong, my new settings don't look as good. LOL. Not sure what to do about the blue specs at this point. They seem to get more pronounced with more samples, at least sometimes....I think i'll just deal with cleaning up the blue dots. I've tried not using an HDR, different kernals and still not change. I'll just deal. Thanks