Hello. I have a big city model in my scene, and I get sometimes these strange shadows on the corners. How can I fix it?
Most likely an issue with mesh normals. They are probably smoothed, causing the shadowed side of the building to bleed over into the bright side. Use 3d modeling software to sharpen the edge of the mesh, or add a bevel to the corner so that the interpolation happens over a smaller distance.
there are hundred of buildings and it will be hard to manually add bevels to all problem parts. May be you know some way to fix it inside the Unreal? May be I can disabe normal smoothing somehow? Or turn normals of. ( I don’t need normal maps, this city is used for bg, but this weird shadows are visible on far distance)
Unreal has built in modeling tools, you can most likely do it there. I haven’t used them much though so I can’t tell you how.
There are also ways to facet edges in the shader. This is done by taking the DDX and DDY of the world position and then taking the cross product of those. This will derive new normals but they’ll be totally flat.
This is the result of mesh normals, not normal maps. You cannot turn it off because it is required for the engine to understand what direction a polygon is facing to properly light it.