Indirect Lighting causes problems with floor/wall tiles

As you can see on the screenshot, enabling indirect lighting causes artifacts on floor and wall tiles. I couldn’t figure out how to fix that. The only thing that works is disabling it, but then I have pitch-black shadows around my spot light sources, and that is not the result I’m looking for.

I could really use an advise here, please.

This is a common issue when over modularizing your level with assets and using static lighting. Each actor, or individual mesh, that is used to assemble your scene will look a little different when using indirect lighting and can cause some of these issues after a light bake. The mesh next to another one cannot reference what the values were for that actor. This is more evident when an actor is mostly lit by indirect lighting.

You can do a few things to help soften this effect or remove it completely.

  • To remove it completely, use a single mesh for the hallway walls, then one for the floor, and one for the ceiling. Or just use fewer meshes so it’s not as evident.
  • In World Settings > Lightmass adjust the Indirect Lighting Quality to a higher value (will increase light build times), and Indirect Lighting Smoothness to a lower value like 0.65 to 0.75, but you may need to try different ones to see what works best for you.
  • Larger lightmap resolution value can sometimes help to reduce, but keep this in check.
  • use other geometry to mask the seams along the wall. ceiling, and floor.

These are just some starting points to look at to reduce the artifact, but it’s a known limitation of lightmass current. It’s something hopefully that can be addressed in the future, but it’s not an easy thing to fix.

I hope this helps.

Tim

Thank you for your answer!
After taking my time and experimenting, i found that it’s best for my level to use dynamic lighting mostly. And static lighting w/o global illumination.
- YouTube - I managed to get decent results by artificially simulating indirect lighting with point lights around the area.