More Samples for Path Tracing?

Is there a way to go above 4096 samples with Path Tracing?

If not, why not?

Hello, there is actually two soft reasons why it’s 4096.

  1. Our sampling sequence is made of 256 optimal samples, that are then reused after that (by shifting dimensions of the sequence), and the more you go past 256, the more you lose the good properties of the sequence towards a pure random one.
  2. After a large number of samples, you really get diminishing results and because of the implementation of our path tracer (unidirectional with next event estimation), they are some setup where it’s will be next to impossible for the final image to converge so it doesn’t make a lot of sense to wait for 100k samples for next to no better results.

However, since those are soft reasons, you can easily modify the upper value of the maximumSamples variable in the script and try :

Don’t forget to reset the override (or remove/re-add it for the new value to be taken into account)

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I mean, that’s true for all path tracers and other brute force like methods, not sure if you mean the returns are extra diminished in this specific path tracer.

I just want something better than my current workflow, which is to render at x3 times the resolution I want and then resize down, which works and I get (almost) clean results, but surely being able to throw more samples at it would be faster?

I’ve just edited the PathTracing.cs file and will see if that helps me enough.

In any case, please consider an official better solution, since my feedback is : the current implementation / sample limit is not enough to get clean results.

For the record, I found that increasing the limit allowed me to have much cleaner results.

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It does helps in some setup, I agree.

It as been added as an improvement that can be tracked here (a few hours is need for the link to be up)

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@chap-unity I saw the sample increase mentioned in the 2021.1.7 release notes. Is this a mistake? I see it’s part of the v12 HDRP package, not the v11 2021.1 uses.

Had to remove and re-add the Path Tracing volume override to get the slider max to update. Thanks again for increasing this value.

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Indeed, if you change default values, they won’t be updated right away on HDRP 11, you’ll need to either delete/re-add the override or reset it by clicking on the 3 vertical dot menu.

This has been fixed only recently in HDRP 12

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