Strange lighting result - See pictures

Unity Engine
1

I am having considerable problems figuring out lighting for my VR arch viz project. I have a house model with around 5.1M triangles. Here is what I have gone through:

  1. Only directional light → dark inside / 100 FPS great performance (as expected)
  2. Added realtime point lights (10-15) → visually great / 20 FPS poor performance
  3. Baked GI with point lights → poor quality at several settings / bakes for hours / acceptable performance
  4. Changed lights to emissive materials → Visually good / excellent performance…

… but some very strange lighting results. Check the picture of a sofa with single white standard material. In many locations lighting works pretty OK with same material, but I have multiple instances of these extreme results with white armrests and black backrests. Emissive light is pretty much directly above the sofa. There is a bed with same material behind it. I have some other issues too like light leaking via ceiling to adjacent rooms, but that is a another story.

Any clue what could cause this?

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2

Have you checked the ‘normals’ on the mesh. Black planes are usually caused by incorrect normals which can be fixed in your 3D app.

You also want to reduce the number of tri when you import and bake in unity, otherwise it can crash. In blender you can use the decimate modifier.

3

After long investigation I managed to fix the issue. I am not sure which setting was the key here, but I changed Directional mode to Directional (not Specular) and and changed Default Parameters to Default-HighResolution.

What made the investigation long was actually time required to build the lighting to the scene. I have about 1.7k objects in the house model all marked static, this is probably makes calculation bit intense for the engine. I am presuming about 6 hours with i7-6700K @ 4.5 GHz.

Nevertheless I am now finally satisfied with the performance and visual look of the model. For convenience baking would have been most logical solution for me, but I just could not get it look good enough. I will have one last go on “Default-HighResolution” and see if that helps. Let’s see how much lightmap data I will have for the entire model.

Thanks for the tri tip iamthwee, I will check if that will create still usable results. Unity mesh compression did nothing in terms of performance.

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4

One thing when using Directional Specular, Double check the import settings on the _Dir Maps, they are/used to be wrong, causing weird shading when importing the lightmaps from a different pc than you baked on (bug in the meta files) if you change import settings on them to be advanced, and check the “Bypass sRGB sampling” that should hopefully help