Hey, Question 1: How do the "direct samples" and "indirect samples" differ? (progressive lightmapper) Looking at the docs, it's never mentioned, the only thing that's explained are "samples" Samples - The amount of samples (paths) shot from each texel. For some scenes, especially outdoor scenes, 100 samples may be enough. For indoor scenes with emissive geometry more will be needed. Ok, so we are shooting that many rays from each texel, to search for colors all around our point. However, why the amount of iluminated dots around the blue sphere stays the same if I crank up Direct samples from 0 to 1000? But, if I change indirect samples from 10 to 1000, only then does it increase the number of texels which had enough sampling rays to "notice" a glowing sphere nearby. Here you can observe how the points notice the sphere, where red arrows are one of such a ray-bouquet shot from 3 texels. Why direct samples didn't affect it? To me changing direct samples doesn't affect anything :/ One weird thing is that Indirect samples cannot go below 10, but direct samples can be negative (Unity 2017.2f03) Question 2: Also, regarding Area Lights, - does it shoot photons out, like MentalRay? Or is it up to the objects to find such an area light, through these ray-bundles as mentioned in this post? That process is also called Final Gather I have a feeling that area lights aren't shooting-out photons, because "Direct Light Quality" is grayed out, and isn't modifiable in Lightmap settigns asset when using Progressive Lightmapper. It's only tweakable when working with Enlighten Thank you!