Thanks. In the lightmap density view, each square in the grid represents the size of the lightmap pixel. This means each square will contain a single light value.
You can see that they are quite large in your model, not enough to avoid leaking between interior and exterior areas. You need to increase the lightmap resolution for that model. You can do it in two ways:
-
In the mesh asset window. Search for “lightmap” in the property search box and you should see a property called “lightmap resolution”. Increase that value and apply the changes. The grid in the level viewport should change right away.
-
You can set the value directly in the actor in the level too. This overrides the value from the mesh asset. This approach is better for when you want different instances to have different resolutions in the same scene (for example, using a lower resolution for models that are outside of the player reach to save memory).