A good Lighting workflow?

I wonder, how you light an environment.

I light everything until its pretty. Then I rebuild the lighting and 15 minutes later, when its finally done, everything looks completely different, way darker. So how am I supposed to create good lighting if the outcome after rebuilding it is completely different from the preview?
Constantly rebuilding is not a real option because it takes so long.

Thanks for your input!
David

If you haven’t seen it yet, I recommend checking out the Unreal 4 Lighting Academy video series. It taught me a lot about lighting. Unreal 4 Lighting Academy - Session 01.1 - YouTube

I’m a big fan of having a small test map with minimal geometry that allows for very quick light bakes to test out different approaches. Sometimes you just have to try stuff and see what happens, but doing so in a full production map can be slow. Building on preview quality and lowering lightmap resolutions is also helpful if you want to just speed up your bake times at the cost of visual fidelity. Once you’re happy with the value and color balance of your scene, you can crank your settings back up to get those crispy shadows back.

If everything is looking dark after you bake, my gut feeling would be that your diffuse textures are too dark or saturated. Try switching to the Unlit viewmode in the editor to gauge how dark your textures are. Here is an example from Epic of a scene that’s bright/desaturated enough to bounce and receive lots of light: https://docs.unrealengine.com/latest/images/Engine/Rendering/LightingAndShadows/Lightmass/94MidToneDiffuseUnlit.jpg (from this page: CPU Lightmass Global Illumination | Unreal Engine Documentation)