Arnold Denoiser

[balazsmd]

Dear Community,

Is there a tutorial for 3ds max 2021 denoising? I do not mean the OptiX denoiser but the actual Arnold Denoiser with the AOVs. The AOV manager is totally different in the 2021 version and I am lost completely. I would really appreciate some video tutorials. 

[madsd]

Do you mean the CPU denoiser?

You need to render out an exr file you load back into the ui and denoise.

[balazsmd]

My apologies but the Arnold Denoiser tab calls it "Arnold Denoiser".

 

What is a CPU denoiser? Do you mean that the Arnold Denoiser only works with the CPU render mode not the GPU? That would explain that even though I added the appropriate AOVs it is still not perform the denoise process. Can you clarify this? Because if

 

I am wasting my time with the GPU renderer for my production render. I thought I could seriously reduce render times for 1080p video renders but if that is an illusion then i need to move on to more serious rendering engines and reconsider my scenes. I also tried everything you recommended in your earlier video on noise reduction but I cannot get a cleaner image (see screenshot). I do not know what I am doing wrong. 

 

[madsd]

Arnold comes with OptiX, which is the GPU denoiser. it works if you have a newer cuda enabled and preferably RTX model.

There is also a CPU denoiser, the one you show in your image, but dont use that if you have a gpu you want to denoise with.

The best thing you can do if you have a GPU and can render with it is to Add an AOV called RGBA its the very top one.

Then tick the "denoise" flag in the AOV line, restart rendering and it will apear in the AOV list so you can swap to it live.

You do not do this in Production mode, you do it in Active shade mode while Arnold just stands and renders the whole time, while you work.

[balazsmd]

Yes I have an RTX 2080 Ti. i would like to take full advantage of it. The .EXR denoised images were created even with the production renderer, so I guess I could just use those denoised images as my final render result? Are these denoised AOVs flicker less than the OptiX denoised ones or they are pretty much the same in quality. 

I also performed what you recommended and added each AOV to the activeshade and fired up the active shade to see the different passes. here they are with current settings (camera AA:2, diffuse:1, specular:1):

 

 

 BY far specular and indirect are the noisies are the noisiest passes. I keep AA at level 3 and you are right does not change the  quality much increasing it. Is this supposed to improve when i increase the specular and diffuse ray depth? By the way not sure if you saw but you cannot change the ray samples for specular and diffuse when in the GPU mode! When I turn the specular and diffuse to 0 I get a very fast render even with CPU. But then I will lose material reflections right? Ok, I think I am getting closer but still I am not sure how to get this resolve. 

[madsd]

Here I added 3 different types of AOVs, the beauty full image the indirect diffuse and the indirect specular, and I also denoised the channels with OptiX, check the small check box in the middle of each line, saying "Denoise"
So you can render some AOVs out without denoiser and the bad ones you can denoise. They render noise free in some seconds, and give it a minute so it sharpens up.

Depending on how you light it, you can optimize a bit on light samples and some clamping, but the actual individual samples are automatic on the GPU at the moment.

[balazsmd]

Very helpful but I need to bug you a little more I apologize. That checkbox in the AOV manager window actually activates the OptiX denoiser? I thought that was a different denoiser there. I almost want to send you my file so you can see if something causes my high level of noise. If you have other ways of receiving files please let me know. The file is over 1.5 GB. 

I also want to emphasize that I care about the production render a lot more than the active shade. That helped me to pinpoint issues as you recommended but I am ultimately aiming for a production quality low noise render of max 120 seconds per frame. That is ultimately my goal. I am now actually concerned that my GPU is damaged or not working properly because my GPU denoised render images are so bad that when the denoiser kicks in it actually distorts the image! I set the ray depth 3 for diffuse and specular as you do on your example pictures but those are even noiser. I assume this makes sense since higher the ray depth the more bounces occur (which then generates more noise). 

But take a look at the GPU set to AA:3 and the diffuse and specular depth both at 1 and then compare that to when I set the renderer to CPU. It is night and day. Even a single 1 point increase in ray depth causes this much noise? Is that normal (see my request above to share my file)? 

GPU denoised and how it distorts the geometry

 

GPU 3AA diff and spec set to 1

CPU AA:3 and diff and spec ray depth set to 1. (same as GPU above)

  

[balazsmd]

Can you also show me this exact scene without denoiser enabled? I am curious of your noise levels. Thank you,

[madsd]

Upload the scene but archive it from max so it becomes a .zip file. it shrinks final size down a lot, and I also get your full light kit.

I see a couple of things we could do to improve the situation.

The artifacts you see, is the incomplete Optix denoiser at work, an image as you see when rendering in active shade, always starts out with zero noise from the first pixel rendered, but the image is very scrambled, over time, the details starts to get more and more refined, so if you stop it before it has rendered long enough you get these artifacts, do not they are not noise, they are unfinished/processed resampled Optix results, after noise has been removed.

[madsd]

If you just want me to have link to zip file stored on a wetransfer or something, then send link PM.

[madsd]

Dont worry about not using Production render.

The whole idea is that we use Active shade when we optimize the scene for rendering, so we constantly have a render view open when rendering and adjusting settings, the adjustments translates to the framebuffer virtually instantly, and you become a machine to adjust a render very very fast, compared to an oldschooler who sits and work in a production environment. You get orders of magnitudes more work and calibrations done than these other folks.

[balazsmd]

How can I send you the link directly? Can I DM you somehow? I like the forum but there are obviously confidential things I do not want to disclose. 

[madsd · Accepted solution]

[balazsmd]

Can you please turn off your denoiser and show me what the scene looks like without it? Thank you,

[balazsmd]

What kills me is that I feel the RTX GPU "real-time-ray-tracing" hype is not real. Or at least it is not production ready to take the CPU rendering's position in production work.

Take a look at when I enable adaptive sampling with the GPU (and leave the AA samples Max at 20 default) I get an almost perfect result! My AA samples max is at 20. they recommend 50-100 and yet the result is almost perfect.

  

I would be totally happy with this result even without denoising, except that it takes 20 minutes per frame(!!!). That is punishingly long. That should be not more than 5-6 minutes! Where is the real-time raytracing in this? This technology is not ready to replace CPU rendering in my opinion. There is no way that if I render with CPU for 20 minutes on the same scene, I will not get a way better result. So no need for an expensive RTX card, just get a threadripper or a xeon...Anyway. Let me know what you think.

[ryan_lepianka]

Thank you for this discussion!  I do not use 3dsmax that often for animation anymore.  About a year ago I decided to try the GPU renderer because I have a Quadro RTX4000 and I wanted to see what the hype was about.  I'm doing the first animation I've done in a year and could not figure out why the images were so noisy.  I then learned a little about the EXR format and using the Arnold denoiser, but really for as often as I do this, the simplest solution is the best.   I am never going to get all of the necessary steps into procedural memory enough to make fiddling with GPU rendering worthwhile.  I've switched back to CPU rendering.  Thanks again for posting your struggle with this!