Weird shadows over brush generated static meshes

i’m having some unexpected shadows over some static meshes i’ve generated from a “box brush”.
how i’ve reached this bug:
i’ve generated some static meshes from the box brush, all fine, when i build the lighting some parts of the meshes became black (like there’s something casting a shadow over it, but there’s not), i’m using a skylight (with the epic courtyard cubemap) and a directional light (intensity 4, color=30,100,195), i’ve tried to remove both lights and readd them, i’ve noticed the weird shadows appeared after adding the skylight (things seemed ok with just the directional light)
there are 2 sidewalks in this example, the meshes from the right sidewalk have the weird shadows, from the right sidewalk it’s alright.


light only:

This is normal behaviour for anything you made out of brushes, you would need to open your mesh in a 3d program, weld vertices, clean up uv’s, smoothing groups, etc. and it will work.

Ue4’s brushes arent a replacement or alternative to modelling so dont use them like that :slight_smile:

thank you but what you define as “normal behaviour”? you mean it i’s a known issue or it’s perfectly acceptable and expected?
and what’s the correct use for brushes at all? is there any use for brushes? i always looked at them like “unreal isn’t a place for modeling, but if you just want a box or a primitive form you can use this”

When you convert a BSP brush into any static mesh form you have to also assign the lightmap otherwise you can get errors like this as well. Also because of the way BSP brushes are generated when the lightmap is packed you can notice some seam/edge errors with your light bake that you’ll need to correct in an external application.

For info on setting the lightmap to the correct coordinate index follow this part of my Lighting Troubleshooting Guide.

ty Tim, i’ve tried to change the lightmass resolution before (it actually made it worst) but i’ve not changed the light map coordinate index, this was the problem.