AA Samples VS Denoiser

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lacilaci
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AA Samples VS Denoiser

Post by lacilaci » Wed Aug 08, 2018 6:16 am

I'm interested in the tiled sampler cause it seem to allow use both cpu and gpu even when scene wouldn't fit into gpu memory.

I wanted to try and find out how AA samples affects performance and I found it not working very well with denoiser. What happened was using 16 AA samples somehow breaks denoiser. At first I thought maybe since it needs more passes to make denoiser work properly so I left it run longer but didn't help at all, then I thought maybe it's broken only with OpenCL, so I switched to CPU but didn't help either. BTW I didn't take screenshot but the AA at 16 was waaay cleaner than AA 1 at similar time, yet denoiser completely failed I don't know why.

Another thing that I find weird is that I use i7 4770K and a 6GB gtx 1060. In cycles it would seem using cpu+gpu would roughly double the performance compared to rendering 4770K. However using 16 AA samples with luxcore seems to be pretty damn fast using cpu+gpu but cpu is waaay slower on its own. Way slower than half the performance, maybe more like 1/8th (didn't do the exact math) is this behavior normal?
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cpu_longrender.jpg
opencl_quick.jpg
opencl_quick_AA1.jpg

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lacilaci
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Re: AA Samples VS Denoiser

Post by lacilaci » Wed Aug 08, 2018 6:41 am

Just posting another example of the issue here:
Rendered in the same time see how much cleaner the AA16 setting is, so obviously it's what I'd like to use, however denoiser doesn't work.
With AA1 denoiser works but since it's not enough samples for good quality I'd still have to render for way longer...

EDIT: It also turns out that using default AA samples of 3 is introducing the denoiser clamping and flattening the highlights, whereas AA 1 doesn't clamp/flatten highlights at all.

EDIT2: In the same view and scene I'm not seeing issues or clamping usin sobol sampler... So I guess it's only related to "tiled" sampling? Can this be fixed?
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aa_vs_denoiser.jpg

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lacilaci
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Re: AA Samples VS Denoiser

Post by lacilaci » Wed Aug 08, 2018 8:28 am

Yet another issue is, this scene is mostly empty.
Full project was rendered using cycles using mostly 14GB ram(and it's still not a big scene) and it wouldn't matter what resolution I render 4K 8K still almost no memory footprint.

The issue here is that this scene atm almost empty and no textures is taking around 3GB ram without rendering (that's normal) not much more rendering at 1K but close to 11GB at 5K and it reached 26GB on denoising phase.
I would not be able to render full project in 4K with 32GB of ram. And that's not even that big of a project.

Are there ways to optimize this? Is this framebuffer taking memory? Or something else? Could maybe tiled sampling be optimized to minimize memory usage?

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B.Y.O.B.
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Re: AA Samples VS Denoiser

Post by B.Y.O.B. » Wed Aug 08, 2018 10:50 am

I think this might be related to this issue: https://github.com/LuxCoreRender/LuxCore/issues/120
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Dade
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Re: AA Samples VS Denoiser

Post by Dade » Wed Aug 08, 2018 10:58 am

Are you using a single pass tile rendering ?
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lacilaci
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Re: AA Samples VS Denoiser

Post by lacilaci » Wed Aug 08, 2018 11:01 am

B.Y.O.B. wrote:
Wed Aug 08, 2018 10:50 am
I think this might be related to this issue: https://github.com/LuxCoreRender/LuxCore/issues/120
Yes, judging by the pictures it seems to be related.

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Re: AA Samples VS Denoiser

Post by B.Y.O.B. » Wed Aug 08, 2018 11:38 am

lacilaci wrote:
Wed Aug 08, 2018 8:28 am
The issue here is that this scene atm almost empty and no textures is taking around 3GB ram without rendering (that's normal) not much more rendering at 1K but close to 11GB at 5K and it reached 26GB on denoising phase.
I would not be able to render full project in 4K with 32GB of ram. And that's not even that big of a project.

Are there ways to optimize this? Is this framebuffer taking memory? Or something else? Could maybe tiled sampling be optimized to minimize memory usage?
I also noticed that the RAM usage of LuxCore seems to be higher than I would expect.
I documented my findings here: https://github.com/LuxCoreRender/BlendL ... issues/151
Dade wrote:
Wed Aug 08, 2018 10:58 am
Are you using a single pass tile rendering ?
@lacilaci
By default, BlendLuxCore uses multipass tile rendering.
You can switch it on/off with the "Multipass" checkbox:
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lacilaci
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Re: AA Samples VS Denoiser

Post by lacilaci » Wed Aug 08, 2018 11:56 am

I was using default/multipass rendering in all cases

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