I created a brush or loaded a prefab and after compiling my map,
parts of my brush dissapeared!! When I try to re-texture the brush, the
result is the same!!
The corner points of your brush could be off the grids and will give this error, select the brush and press ctrl + g to fix this, if it doesn't work or the brush will get a weird form, just remake it.
Yes most likely a degenerate plane or bad normal. I bet you're getting either of these errors during the compile (first stage). Like At0mic said best remake the brush.
