Optix denoiser problems

[Anonymous]

Can anybody send me a simple Max 2018 project file example with this active and working? It can be simply with primitives as long the denoise works.  I have not been able to get it working correctly, even using last version of Nvidia drivers or the version before and last Arnold.

[madsd]

Attached a max 2018 file that works fine.

If it does not automaticly render the denoised AOV there is something wrong with your GFX card settings/Drivers. It is set up to work as soon as you hit render button.

Remember you can swap between the AOV's in the frame buffer, I set it to the denoised version, now - you can just move around scene, and see the denoised image materialise almoste instantly, I cut it prematurely at samples so you can clearly see the noisy RGBA beautry and compare with the denoised version in the other AOV channel.

[RGhost77]

I don't think that the problems in the drivers. It seems Optix works pretty bad with large dark areas. It's no problem if you do not use after denoise exposure controls, but if you do it all this artifacts totally mess final image.

[madsd]

Yes his issues is something else, he cant even get it started.

Your issue is that you just use 1 sample on the camera AA or even 0, you the denoiser passes are bound up on the amount of Camera AA loops there are, so by using very few or only 1, you will get artifacts, you will get less and less artifacts the more samples you run through, this is the nature of the denoiser implementation.

See here to replicate your issue and how to avoid it.

[Anonymous]

When I try your file it works. When I try to reproduce it doesn't.

I have compared many settings between you scene and what I can do and I'm not able to find what is different.

I include here the scene, that in this case shows a black denoise.

[madsd]

You have 2 environment features going, both the stuff in the environment slot and a dome light with the environment.

I rebuild your case, avoid using Environment slot entirely ( no need for it ) and just use the scene node to drive the Physical sky.

Denoiser works fine.

Your scene crashed my max, so you have done something in it which isnt normal, what i dont know.

Check attached file.

[Anonymous]

Your file again works but it makes not noticeable changes in the image. Only removing the reflections in the shadow and the rest is the same.

It seems the problem comes when using exposure control in environment and effects. But then how can I can control it? It works if I simply delete the exposure control and change the light settings individually with a intensity that looks OK without it. But this doesn't give me a global control of the scene exposure. A skydome by default is too bright and I need to reduce it drastically instead changing the global exposure etc.

This is simply a first impression, more factors could be influencing. 

[madsd]

You can use the color grading tools with denoiser and it will work fine.
Don't use the environment slot for your environment, use an Arnold light
you turn into a domelight and use a Physical sky map in the Texture slot.

Set the Dome light to 1 intensity and 0 in exposure, this will give you a 1:1 exposure. The 1 and 8 is not right default.

- Mads

[Anonymous]

What system I should use for Arnold for global exposure control regardless of denoise?

For any kind of Arnold light.

[madsd]

In max 2018 you can download VFX+ it is a free framebuffer with everything from exposure, to loading LUT files, contrast, whatever. It is not compiled for 2019 yet.

http://www.monotoneminimal.com/vfb

Using the stock max color grading tools just swap to physical exposure control. You have:

Bottom
Mids
Highs
General exposure
Saturation

Often these are enough for a long stretch. Else download the free framebuffer and you got an awesome grading tool working with the render engine directly.

Also, make a scene that justifies denoising a bit better may be a good idea, a teapot on a plane with a lamp on doesnt reveal that much.

I attached a file where we look into a room, only lit by skylight, it is set to denoise, now try just push render and flip between RGBA and denoised_RGBA should give a much stronger difference between denoised and not-denoised image.

[Anonymous]

Thanks, I have tried to research this and several times appear this:

• AOVs in Arnold do not take the exposure control into account

That could explain why normally denoise doesn’t work with exposure controls ON and the only times it works is when the exposure is similar with the exposure controls on or off, as it is the case of you project file.

This raises the question of how you control the exposure of multiple lights and use denoise at same time.

[madsd]

Not sure I follow what you mean with Exposure not working on the denoised AOVs.

Take a look at this example, this is a denoised AOV with some live color grading, works perfect.

Are you talking about noice.exe the stand alone tool? if yes, then yes that one does not account for various exposure tweaks, you will have to inject the exposure post.

Same goes for OptiX if you save to disk the Exr will not carry the exposure tweaks, you can at all times though save out the framebuffer with any custom grade.

You can load the Exr back into the environment and screen map it and render with the Exposure tweaks and save.

If you want seperate exposures on lights, use the individual exposure settings on the lights.

[Anonymous]

You have set the lights of your scene to look nearly Ok without exposure control, that is when there are not problems.

I have left only the skylight and removed the ceiling. Then I set it with his normal exposure of 8 (as it was 0, unusual for a skylight). Automatically the scene needs exposure control to 15 and in this situation the denoise will appear as a black image (attached file)

It could be that yes the exposure is affecting the display in the render window but the denoise is applied before it. And if the image is too dark or too bright it seems that the denoise is not a fully 32 bit effect and has a limited range (wild guess) I sometimes see it white, sometimes black, sometimes with halos and color distorsions and sometimes with clamped black or white levels.

This is a single light, but could be more relevant when we are working in a large environment with exterior and interior lights and we need to keep a large dynamic range and be able to change exposure without affecting individually the lights.

I'm not sure of this, simply I try to understand why in some situations the denoise doesn't work at all and what workarounds are that doesn't have a negative effect.

I have not yet used the other noise reduction system. I hope first to be able to use in a reliable way the "simpler" one.

[madsd]

[Anonymous]

Are you only modifying the exposure global value of the project I sent? This is what I get that doesn't seem to match your video (unless I'm confused)

[madsd]

First image looks right.

You just need to reset the Exposure on the dome light, so exposure is 0.

Just work with it like that and it will be fine.

You can grade, lift blacks, mids, and highs and exposure in global as much as you want after that.

And if you save the Denoised AOV to an exr, reload it to the environment with the exposure tweaks and rerender it.

Naturally, at a point this will get sorted out, but you can just regrade post as well, its just exposure and low,mid,high.

[Anonymous]

Well, at least I know a workaround. Before I was getting apparently random results.

[Anonymous]

I like the progressive settings for the render that you have there. I certainly will use them.

[madsd]

Yes, they are nice.

Also dont remember, but you can change the bucket size to 16 and set to "random" this will make the framebuffer resolve in a much more uniform way, gradually removing noise and improving AA.

[RGhost77]

It would be good if in future version of max Exposure control would be changed to like exposure in VFB2+ to be real post effect. Because re-render image every time when exposure is changed its huge waste of time.
Yes, I know that I can render image in to linear then correct exposure outside of max, but we talk about usability of Max's feature.

Also would be good to have in Max Color Managment like in Maya.

https://forums.autodesk.com/t5/3ds-max-ideas/implement-color-management-in-3ds-max-support-for-icc-l...