Bad noise, even with 16 AA samples 6 light samples. Geo to big?

[TwigaArts]

Hi lighters and renders,

I am having a problem with an Arnold render. I have a scene, The renders come out slow and noisy.. even though I am rendering on 4xGTX3090's, 16 AA samples, and lights samples at 6.

I rendered a scene before, fast and clean. much lower samples too.

From what I know, the differences between the scenes, in the bad scene. are that the geo is very big, they have ai stander surface shaders, there are render layers, and the geo was exported from blender to Maya.

Any ideas on what might be causing the noise?

I am at a loss google isn't giving me anything useful anymore.

Thank you!

[lee_griggs]

Some screengrabs showing settings and renders would be useful.

Camera (AA): 16 and 6 light samples seem like a lot. 5 and 3 should be more than enough. What other sample settings are you using: diffuse, specular, etc? Are you using the default ray_depth settings?

Some tutorials about removing noise can be found here.

[TwigaArts]

Well, it's a GPU render. it looks great as a CPU render. but I'm paying for a GPU render service and it looks great on another project. here are some settings.

 

[lee_griggs]

Can you post some renders, a log file, and a screengrab of the geo in the scene?

[Stephen.Blair]

16 AA samples for Arnold GPU is not really a lot, unless you're using adapative. In which case, that could be too high.
Did you try increasing Max Camera AA?

Matching Noise on CPU and GPU

Matching noise can take a little experimentation because Arnold GPU uses Camera (AA) sampling only. We recommend you also use Adaptive sampling. Here are some guidelines:

• Set the Max. Camera (AA) in the range of 30 to 50 (depending on the scene, you might go closer to 100). In general, the max samples should be a large value. A large max samples means that the quality is controlled by the noise falling under the threshold, instead of by clamping to the max AA.
• Set the Adaptive Threshold to something like 0.015 or 0.02. For a noise-free render, lower the threshold value, maybe even as far as 0.010.
• Set the Camera (AA) samples to around 3 or 4. One of the few reasons to go higher with AA is for motion blur. The higher the number of Camera (AA) samples, the less of a speedup you'll get from adaptive sampling.

[TwigaArts]

Ok, so I went through my rigs and deleted thousands of unused render nodes. and there is a slight difference in noise but it is still long to render.

Where do I find the render log files?

Is this it?

[TwigaArts]

Sorry, I forgot to send the render, this is at the setting you recommended 5AA 3 light samples. this was an .exr file but I had to convert it to png to send it..

 

[TwigaArts]

I think the Adaptive sampling was it I'm going to give it a try in I render! Thank you both I learned so much!