Basic Q: when no lights in EEVEE, where's the illumination coming from?

Support Basics & Interface
1

Fundamental question: when there are no lights in a scene (in Eevee), where is the illumination coming from?

tnx.

2

If i had to guess, World properties tab, thereā€™s ambient light set to 1 by default.

3

I may have hit that ā€œSolutionā€ checkbox too fast: on my (2.82a) World Properties tab thereā€™s literally ONLY a ā€œNewā€ button, no settings per se at all.

So, Iā€™m Searching the Help on ā€œambientā€, but so far no luckā€¦

4

The default world has a grey color, so you are getting ambient grey lighting.

5

So, eevee is ray tracing from every point in the ā€˜universeā€™?

Iā€™m not fond of the fact that no World parameters are visible before you ā€˜Newā€™ one into existence. After all, the World is always there. The UI should reflect that. :roll_eyes:

6

Yeah, I get it, but you gotta have something as the default when nothing is in place. If you want to configure the world, you need to have a world in your scene

Materials are the same way, there is a default grey material so that you can see ā€˜somethingā€™. if objects were solid black by default, in a solid black world by default, youā€™d get a lot of confused new users.

Eevee uses the world environment and then sorts the lighting coming from the world from each direction, so it averages everything in the top hemisphere to get the average lighting on a face that is pointing up. For a solid color, this is a pretty simple calculation. It isnā€™t true raytracing, but it does effectively sample the whole environment.

This sampled environmental lighting is the basis lighting for all objects in a scene. I believe it is only overridden by irradiance probes. so if you do an interior scene and you have an HDRI environment, your interior lighting is going to be weirdly broken without the probes.

Oh, itā€™s also effected by the ambient occlusion. The ā€˜bent normalsā€™ checkbox changes the direction of the lighting sampled from the world by looking at what direction is occluded and what direction isnā€™t. It finds the average normal of the un-occluded area, then uses that normal to sample the environment lighting.

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7

Good stuff: thanks for the instruction. :+1:

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