Struggling with transparent acetate like plastic, weird artifacts

[mkmkmkmk]

Hi,

Getting some weird artifacts and not sure what im doing wrong would love some advice. Material is a custom tortoise shell material (forgive me cant recall who made it) For a pair of glasses im trying to render. Any thoughts?

thanks in advance!

Ray bounces 37
indirect bounces 43
shadow quality 2.9
self shadows on
everything else off

[mkmkmkmk]

Apologies if this in the wrong section!

[DMerz III]

I would render far more samples for this complex of a material. Right now you're using 16. I'd try at least 64 and see if that cleans up the image. Depending on your machine, this might take some time, in which case, turn your shadow setting back down to 1, this will significantly decrease your overall render time.

Hope that gets you going in the right direction.
PS. I don't think you need THAT many ray bounces either, but I can't see what else is in your scene, try cutting that in half to decrease render time as well.

[mkmkmkmk]

Ok will try thanks!

[DetroitVinylRob]

mkmkmkmk, though I agree that much of your noise issue is probably related to samples and ray bounces, perhaps your abbe number is a bit low. For automotive lighting I find a sweet spot around 64 Samples/33 Ray Bounces. Just worked through a very similar issue. Hope this is helpful and doesn't further the noise.

Here are some basic, ballpark examples and a decent reference site...

PC 27.86
Cellulose 54.00
PMMA 53.18
Cellulose Acetate Butyrate 82.00 (Refractive index 1.478)

https://refractiveindex.info/

[Speedster]

Try unchecking (if not unchecked already) "Global Illumination Cache" on the render tab, Render > Options, bottom left.  This almost always screws up plastics.
Bill G

[mkmkmkmk]

Awesome thank you both so much for the feedback! Will try these tips