Testing samplers and engines

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ariellev
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Joined: Wed Feb 06, 2019 2:04 pm

Testing samplers and engines

Post by ariellev » Wed Feb 06, 2019 3:12 pm

Hello, I was having trouble with a scene for a long time with 18 lights in arbitrary placement around a large void, a complex-shaped reflecting subject with two lights and caustics, and very high lighting contrast. I was getting very many fireflies, so I tried the bidir engine. I want to make this example to show just how big this difference is. This is a version of the scene with a lot of things scrubbed from visibility due to an error I made.

Here I have rendered with the path renderer twice, to 500 samples, on two GPUs (HD 7850 and RX 570).

With the sobol sampler, 40% adaptivity, forgot to record time but it was less than half the time of the metropolis sampler:
1 - PATH SOBOL.png
With the metropolis sampler, untouched sampling settings, 4 and a half minutes:
1 - PATH METROPOLIS.png


Next I have rendered once with bidir and metropolis. I have limited this render to 40 minutes as I have a very slow cpu which is slightly broken (being replaced soon), I don't want to stress it too much and cause too many wrong results, and want to upload this today. As I write this it has been going for a minute and has reached three samples per pixel.

While I'm waiting for this I might as well say, since I'm bored: I chose luxcore due to the nicer reflections than cycles and is better for local rendering on my amd hardware, and even as I'm finding it's missing things currently, I believe it is right to stick with exciting new tech before it's considered useful by the crowd so that it becomes useful to the crowd.

okay it's done rendering, got to 116 samples in 40 minutes, here it is
1 - BIDIR METROPOLIS.png
Something to note: in the path examples, the more samples I pumped through the more fireflies there would be, 500 is a little high

so if you're having trouble with fireflies in a scene with complex lighting, try the bidir engine

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Dade
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Re: Testing samplers and engines

Post by Dade » Wed Feb 06, 2019 3:17 pm

ariellev wrote:
Wed Feb 06, 2019 3:12 pm
so if you're having trouble with fireflies in a scene with complex lighting, try the bidir engine
Or just use variance clamping option and/or denoiser :idea:
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ariellev
Posts: 2
Joined: Wed Feb 06, 2019 2:04 pm

Re: Testing samplers and engines

Post by ariellev » Wed Feb 06, 2019 3:21 pm

Dade wrote:
Wed Feb 06, 2019 3:17 pm
ariellev wrote:
Wed Feb 06, 2019 3:12 pm
so if you're having trouble with fireflies in a scene with complex lighting, try the bidir engine
Or just use variance clamping option and/or denoiser :idea:
I am using the clamping option, I adjust the value so much and try all the recommended values, it really doesn't help with this scene

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