I was wondering if the samples matter at all when you're baking a normal map. I don't think so, but I just want to make sure.
2 Answers
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No, samples have no effect.
A sample is a measurement done by shooting a ray into the scene. These rays scatter randomly inside the scene, so the more samples the more accurate information about the scene.
Normal map needs only 1 sample because there is no scattering. From every pixel of the normal map mapped on your lowpoly in the scene you need to send only 1 ray till it hits the highpoly, and store the surface direction into the normal map pixel. There is no additional random scattering after that, you get the exact finite value just there.
answered Jul 19, 2017 at 14:52
Jaroslav Jerryno NovotnyJaroslav Jerryno Novotny
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$\begingroup$ This seams right, but if increase the sampling the baking time increases accordingly, I don't know why, as well as the Denoising $\endgroup$ Commented Feb 17, 2021 at 16:38
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Samples do affect baking -- but ONLY the anti-aliasing to a small extent. However, if you are baking things like Ambient Occlusion or the Direct/Indirect lighting options in the Diffuse pass, the sample count does matter. Observe this example below, a close-up section of a 1024 x 1024 baked image. While there is an appreciable difference between baking with 1 sample and baking with 16 samples, there is very little difference between 16 and 128, and (not shown in this example) almost no change whatsoever between a bake at 128 samples and a bake at 2048 samples. (Click the image to view at a larger size to see the anti-aliasing better. Depending on your web-browser, you may need to download the image to see the true difference, because Google Chrome adds heavy anti-aliasing of its own on top of the image).
However, if you oversample the image by baking at a larger size and then scaling it down later, you will get MUCH BETTER anti-aliasing results. In the lower right of the image below, notice how the image rendered with 32 samples at 2048 x 2048 and then scaled to 1024 x 1024 in GIMP using the "No Halo" setting has far superior anti-aliasing.
