Black dots with opacity falloff

[akvahouse]

Hello, I have a problem when using falloff in the opacity slot. There is always an uneven transition to black, which makes it difficult to make the effect smooth.

Can you tell me how to solve this problem? Thank you for attention!
A. Operating System, including version win10
B. Graphics Card(s) model gtx 1080ti
C. RAM Capacity 32gb
D. Nvidia driver version 388.13
F. OctaneRender plugin version 3.07 - R2
G. Host application version: Cinema 4D R19

[milanm]

Hmm... It looks like the problem is a hardware issue and it's located somewhere between your chair and your monitor

Try decreasing the Path Termination parameter to zero. That parameter is used to cut off rays that are too dark in order to make our rendering faster. Depending on our Imager settings we can actually make the image bright enough to see them and that manifests exactly like in your image and it creates a lot of problems when adaptive sampling is used. One way to fix this is to lift the lighting a bit in your scene, either by adding additional lights or adding a texture in the AO Environment slot. Or you might have to adjust Expected Exposure in Adaptive Sampling settings. Also Opacity does tend to cause a bit more noise compared to specular.

Edit: Ah, forgot to mention that there is also an issue with the Camera Imager where using the default order (Response, Gamma, Lut) could cause cliping like that. Switching to 'Gamma, Response, Lut' and adjusting gamma could fix it. But that's still not a bug in the plugin.

Either way if this was a bug it would be all over the (core) OctaneRender topics and I didn't see anything like that there yet.

I hope this helps.

Bad, bad idea to post it as a plugin bug report, god help you when @aoktar sees this.

Regards
Milan

[akvahouse]

Milanm thanks for help, it`s adaptive sampling couse this issue!

[aoktar]

It's looking like related to logic of adaptive sampling. So I'm happy to move this topic from BUGS section. Thanks for reporting!