About CesiumSunSky light error through of 3dtiles question

CesiumSunSky through of 3dtiles.

It doesn’t block CesiumSunSky as correctly as the terrain.

What should i do solve this question?

This phenomenon same in CesiumForUnrealSample project.

Hi @GunOmniscience,

I think this is related to the KHR_materials_unlit glTF extension. Lots of photogrammetry models use this extension to indicate “lighting is baked into this model, don’t light it at runtime.” In Unreal, though, we don’t use a true unlit material, because it’s awkward to make that work with the SunSky lighting model that is typically used in Cesium levels. The emissive light intensity has to equal the rather high intensity of sun lighting to be visible when the rest of the scene is in direct sunlight… but then when the rest of the scene isn’t in direct sunlight, the emissive “unlit” light would be much too bright. There’s no obvious way to tell Unreal to simply draw the pixels in their raw color.

So instead of using an unlit material, we render unlit models by making their normal point in the globe’s up direction everywhere. This works reasonably well when the sun is roughly overhead, but can look a weird when the sun is near the horizon. I’ve not quite sure what to do about this, but I’ve written an issue to track it:


Thank you so much.:blush: