Level's BSP Model geometry is broken

  • Build Type: Fresh Binary from the Unreal Launcher
  • Build Version: 4.16.2
  • Description: Just start a new empty level, turn show flag “mesh edges” on, and start playing with BSP brushs. Add a couple of brushes, move them around, and eventually you will see the model geometry goes haywire (you might have to overlap some brushes to trigger). Creating a static mesh from one brush seems will result in an updating and fixing of all other brushes (sometimes), but it does yield a proper static mesh (most of the time). I would like this to be fixed because I am trying to define my own C++ brush builders (ie the TorusBuilder brush below).

Hey instantmelanie,

Could you be more specific in your description of what you mean by ‘haywire’?

The only thing that seems a bit odd is the flickering that occurs which is caused by Temporal AA and not easily fixable. A bug has been entered for this flickering behavior (UE-30764)

Thank you,

Andrew Hurley

Yes, look more closely at the first image. There are edges on the brush that shouldn’t be there. The second image shows how the extra edges disappear once I convert the brush to a static mesh. My custom torus brush better illustrates the issue but I just want to know why the engines default brush has these extra edges, or at least appears to.