BSP brush converted to Static Mesh Behaves Weird

I am Using Unreal Engine .5 and Brushes That were converted to Static Meshes Behave Weird as below. Situation is not present if lighting is unbuilt. I already updated the lightmap resolution of the mesh and light map coordinate index of the mesh and it seems to solve absurd lighting, but creates what is in the attachment.
anyone know how to solve it?

how it must be?

how is it wired now?

what is the problem?

I could not understand what is wrong in that image :)))

This happens because you used bsp, when ue4 converts bsp to static meshes, it random connects vertices together with lines… and since bsp is not made as a replacement for modeling software like blender, maya, max, modo, etc this is the result you will get.

the only thing you can do fix is it to get a 3d program and recreate it there.
bsp should ONLY be used to block out a simple level, afterwards you use 3d modeling software to create environment props like that archway.

so, DONT use bsp to create meshes like these… its not made to do that.