Dead white pixels even after convergence

[matt-42]

Hi, Even after convergence, some noisy white pixels remains in the scene:

Is there any workaround ?

[passariello]

mmmm, it's part of the game. You need to bake many and many time to try to remove the noise. Nvidia have made a optimix algorithm to reduce time an noise. We need something similar. At the end the noise is normal.

Dario

On Wed., Aug. 26, 2020, 6:59 a.m. Matthieu Garrigues < [email protected]> wrote:

Hi, Even after convergence, some noisy white pixels remains in the scene: [image: image] https://user-images.githubusercontent.com/846584/91312711-d14f8300-e7b4-11ea-9f93-6bfdc62b6c61.png

Is there any workaround ?

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[matt-42]

Thanks for your answer. What do you mean by "bake" ? Do you mean that the noise is supposed to eventually dissapear if we leave the rendering run forever ?

[matt-42]

If noise is normal, it seems like we can remove most of it with a simple filter assuming local coherency.

[passariello]

Some information are here:

https://alain.xyz/blog/raytracing-denoising https://www.scitepress.org/Papers/2018/66558/66558.pdf http://www.cs.cmu.edu/afs/cs/academic/class/15869-f11/www/readings/parker10_optix.pdf

Without GPU support I think that it is really hard to remove these "white points", It's part of the problem of the "caustic" approach of path trace. Optix is really useful in this sense.

I hope to see soon a GPU integration in this project.

---

Dario Passariello Principal Software Developer Trainer and 3D Expert https://dario.passariello.ca mobile: +1-778-318-2645

On Wed, Aug 26, 2020 at 9:22 AM Matthieu Garrigues [email protected] wrote:

If noise is normal, it seems like we can remove most of it with a simple filter assuming local coherency.

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[matt-42]

Another note: the white dots seems to increase when we let the rendering run.

Thanks @passariello for the links, I'll have a look.

[elfrank]

Hi, Even after convergence, some noisy white pixels remains in the scene:

Is there any workaround ?

@matt-42 do you have glass on the scene?

[matt-42]

No glass. But I think this is due to a low roughness on materials. When I increase it the white dots dissapear...