Baked lighting issue

Questions & Answers
1

I’m quite new to Unity and i try to understand how i obtain this bad lighting render from my scene.
See the shaded/wireframe scene on first screenshot, and the result (black one with yellow dots) after generated lighting.

The scene consists in a terrain, a museum building (you see trees and grass through the window on the left), a directional light (outside, realtime), and mixed/baked spotlights inside the museum (oriented to picture frames on walls). Of course, there’s nothing in my scene (models, lights) that would explain the yellows dots. Materials on the walls are standard white whit slight normal map to get concrete effect.

The museum building model is a blender model exported to DAE file, the “Generate lightmap UVs” is checked, and the object receives and casts shadows, contribute to global illumination.
Same settings for picture frames.

I understand that i may not be using the best render quality parameters (i tested differents samples and lightmap resolutions), but it seems to me there’s some other matter here…
so if you have any clue, please tell me what i could do to fix that ?

Thanks for your help

2

This is a tough one to work out, in my experience it is nearly always something wrong with the model. And usually when the light scatters like that it is something to do with backfaces/open faces on the model

What pipeline are you using? On your materials do you have the option to set the “Render Face” dropdown to both? If so change that to “Both” and try bake again.

3

Thanks @MickyX for your answer !

I use the built-in render pipeline, and my model seems to be quite standard : no specific export option from Blender (the default ones from .dae), and my model imported in Unity has the default options (see screenshot on the right, materials section’s set to import/embedded materials ) …

Even on standard cube created with Unity i get this dotted render (see screenshot, walls are Unity standard cube), that weirdly even seems to consider the external environnement (trees and grass behind the wall responsible for this greenish dotted effect on wall ? or just some kind of grass reflection from the ground ?)

I’m certainly missing something obvious here …