Render is grainy no matter what. Tweet

[Pectabyte]

Hey guys, I’m creating a series of renders for my science fiction series, The Amaranth Chronicles.

https://theamaranthchronicles.com/media

I’m having trouble with Octane Renderer for 3D Studio Max. I've searched all over the web and there are a lot of "my render is grainy" posts but nothing seem to work. No matter the values I give the Kernel or Camera, my renders are still coming out incredibly grainy. This is the result of a 30 minute render on an RTX 2080.

What am I doing wrong? How can I remove this fuzzy, grainy quality to the image?

[frankmci]

I'm not a MAX user, but off the top of my head, I'd suggest first turning on the AI light, since this is exactly the sort of scene it works well on, enable Adaptive Sampling, and I'd also reduce your GI clamp to something like 10 or 100. If the AI light doesn't do much for you, you may want to simplify the shape/number of polygons on light emitting geometry, plus manually set your Sampling Rate for each emitter, to give priority to the ones that matter most.

[Pectabyte]

That made it much, much worse.

[frankmci]

That made it much, much worse.

Oops.

Which "that" do you mean? Did you try those suggestions incrementally and in differenct combinations?

How are you generating all those lights? Looks like you have 100+ individual sources. Are they light primitives or individual pieces of texture driven, light emitting geometry? A combination of the two? Do you have different materials for each light type? Are you faking any lighting with luma maps on textures?

Have you tried isolating each major group of light sources to see which might be the most guilty culprit? There's an awful lot going on in that scene, illumination wise, so simplifying may help you track down the issue more quickly.

[Pectabyte]

I tried all three of your suggestions at once. Any combination of the 3 leads to a crash.

The majority of the lights are texture base and there are 3 different lighting materials. Its not the lights. Its the overall image.

[frankmci]

I tried all three of your suggestions at once. Any combination of the 3 leads to a crash.

The majority of the lights are texture base and there are 3 different lighting materials. Its not the lights. Its the overall image.

If those are causing a crash, you may have a deeper problem.

If it's not the lights, are you saying that you still get overly noisy renders with, for instance, a single Daylight lightsource? Can you share an ORBX of the scene?

[Pectabyte]

Its fine if I place a day light source in there. Its literally only in low light situation. I have no idea what an ORBX scene is, but this file is several gigs worth of assets, if that makes a difference.

[frankmci]

Its fine if I place a day light source in there. Its literally only in low light situation. I have no idea what an ORBX scene is, but this file is several gigs worth of assets, if that makes a difference.

OK, so it clearly is the lights, then. Yes, low light is inherently noisy, (and even more of an issue with a high number of light sources for CGI). That's an unavoidable fact if you are ray trace rendering, shooting a film camera, or a shooting a CCD camera. Fewer photons means more noise.

ORBX is the native file format that Octane uses. It's essentially what the render engine is actually rendering, and what you can examine and edit in the OctaneRender stand alone application. It's also a good format for sharing while troubleshooting, since it's not tied to any given 3D host package.

You have many, many lights in your scene, but you really should not need 15,000+ samples to get a good looking image. Some light sources are more important than others, and you need to figure out how to use them optimally. It is not a trivial problem. Normally, the AI Light does a pretty good job of this, but not always. As I mentioned previously, I suggest you isolate different logical groups of light sources and see which ones contribute the most to overall scene illumination, and which contribute minimally to inter-object illumination. Then use the Sampling Rate for each source to weight them accordingly. The Sampling Rate is a relatively weighted value, not an absolute value. It doesn't matter if you use 1 and 0.1 or 100 and 10. They have the same relative weight to each other.

You should be able to get a much cleaner image, much faster than what you've got now. In addition to optimizing your lights, definitely read up on Adaptive Sampling, Denoising, AI Lighting, and the GI Clamp value. Since you are having crashes, you may also be running into a low memory issue, and may want to look into Out of Core RAM use.

[whersmy]

If its possible export to .orbx (possilbe from 3dsmax plugin) and I`ll try and give you a few pointers.

Indeed all of the above tips are useable