I have a few meshes that essentially are just fancy planes. I'm planning to use these as repeatable tiles to construct my world from. However, I'm getting strange lighting issues (the animation below is with all static meshes and after waiting for the lighting build to complete): The issue appears to be that ambient lighting is completely ignored on some of the tiles. Here's what happens when I turn ambient lighting up and down: My best guess is that Unity is doing some interior/exterior determination to decide whether a mesh is influenced by ambient light and that this logic is somehow failing for my shapes. Can anyone explain this or better yet, provide a workaround?