Trying to reduce noise in path traced renderings

I am trying to get familiar with path traced rendering, in combination with movie capture. My impression is that certain reflective/transparent material is rendered with a lot of noise that is particular visible in movie sequences. In the render settings, I have denoising activated. Apart from that, I experiment with different values for Samples per Pixel and also motion blur. My impression is that when spp is set to about 16-32, the image overall looks clean, but I have a lot of noise in reflective material. If I increase spp further, the rendering time increases quickly up to an amount that I cannot handle anymore. Is there any other settings I can try? What are realistic settings for spp?

Right now, I get these results with different spp settings:




With ssp=512, I still see a lot of noise.


Hi Bruno,
Thanks for the question. Yes, unfortunately, certain materials are going to be more noisy than others. The denoiser does it’s best to get rid of all noise, but certain materials and surfaces are going to fare worse than others. in general, I advise an SPP of at least 256, to get the best results. Sometimes going as high as 512, yes. It just depends on the scene. Unfortunately, there is not a lot of workaround for this, but just more rendering time.

I have to say, though, that in your examples, the 512 version looks really nice. I don’t think you can get less noise than that. You don’t want the rendering to look completely flat and devoid of texture.

Thanks Richard,

good to have that clarified. Then we will have to accept and buy more GPUs.


Try to reduce noise on shiny surfaces by adding a little roughness. Look at what else you can do to reduce noise. Maybe more lighting, more exposure, adjusting materials. Also see how far you can push the RealTime renderer as well. With AOVs and mattes you can even combine passes from both

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Thanks Richard for the additional advice. I will try to get myself familiar with these concepts.


Also there are rumors of new rendering solution coming,
and real-time rtx is getting better all the time.

We are always making signifant improvements to the quality and speed of the RTX renderers.

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