Since Eevee isn’t a pathtracer like Cycles which calculates physically correct how the light rays are bouncing through your scene, it can’t calculate indirect lighting automatically like Cycles. But we can fake this with “Irradiance Volume” light probes which are aligned in a 3-dimensional grid. Each light probe in that grid acts as a 360-degrees camera which takes a picture of its surrounding during the baking process. After the baking, these light probes act as projectors of their images. You have to take care of that you don’t place a light probe inside an object because it would then take a black image. It can be a lot of tweaking until you have placed these probes well enough so that they only photograph what they need and until you’ve set it up right so that only the object receive a projection that need this. But I’m also still an Eevee beginner.
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