Noise problem

[Aymeric_FX]

Hey guys, tried everything I could think of trying to fix this issue.

I'm rendering a simple animation, but this specular highlight on my material keeps flickering like crazy (denoiser is on).
This always and only happens when I use the Octane Daylight module - Had this issue like 5 years ago and it's crazy that it hasn't been fixed since then. I've avoided using it for years now but this particular project required its use.

I've tried:
Upping the samples like crazy (I'm at 150,000 - SRSLY lol) - doesn't have any change
Caustic blur to max settings
Adjusting ray epsilon - doesn't work
static noise (on/off)
hot pixel removal (max)

the ONLY thing that did something was adjusting the GI clamp - but this changed the lighting too dramatically - so it's not an option as this is just a render region and thus it needs to composite into the original shot.

The GI Clamp is currently set to 100.

Quick example of the issue has been uploaded


Anyone got some ideas? I feel even a million samples won't help. I'm stumped.

[Aymeric_FX]

octane settings screenshot attached

[aoktar]

don't use hot pixel removal. It's like blurring something and gives flickers if there are much fire-flys. Better to play with specular intensity in materials and keep gi_clamp low as much as possible. And use adaptive sampling to let the renderer may concentrate for this areas.

[elsksa]

What Aoktar said.

I will just clarify this part which may get misunderstood:

(...) and keep gi_clamp low as much as possible.

Bascially, the right (lowest) value that does visually (beauty or through AOVs) not / barely make a difference.

This is worth reading as some of the settings have been misused.

[Aymeric_FX]

don't use hot pixel removal. It's like blurring something and gives flickers if there are much fire-flys. Better to play with specular intensity in materials and keep gi_clamp low as much as possible. And use adaptive sampling to let the renderer may concentrate for this areas.

I was just showing that I tried it to see if it would render out different results.
Setting the GI clamp to anything lower than 1000 gives off unrealstic lighting in this scenario. I'll give adaptive sampling a go and see how that goes!

[Aymeric_FX]

What Aoktar said.

I will just clarify this part which may get misunderstood:

(...) and keep gi_clamp low as much as possible.

Bascially, the right (lowest) value that does visually (beauty or through AOVs) not / barely make a difference.

This is worth reading as some of the settings have been misused.

I just read that, nothing really new + doesn't solve the problem. Putting the GI clamp below 1000 ends up giving off an unrealistic look, adjusting the specular intensity makes the material look flat,
I'll try adaptative sampling and see how that goes! Thanks.

[elsksa]

I just read that, nothing really new + doesn't solve the problem. Putting the GI clamp below 1000 ends up giving off an unrealistic look, adjusting the specular intensity makes the material look flat,
I'll try adaptative sampling and see how that goes! Thanks.

Definitely worth giving it a scrupulous read, as the initial message indicated misused settings.
Values are not set randomly. There is a logic behind all of them and how they work together.

Adaptive Sampling is beneficial in most cases.

Render settings are not everything, though. A sane scene with careful materials, geometries, etc, is as important.