Weird texture/BSP geometry error?

Hi, I have experienced this quite a few times recently. Look at these two pictures.

As you can see it looks like floor bsp / wall bsp have changed its geometry and goes in random shapes also down onto the wall bsp. They show like that in the editor as well as in Play Mode. If i duplicate the floor/wall/ceiling and removes the old and just replace it, they disappear. But evetually they come back, but not on the same places, it can be totally different walls/ceilings/bsps.

Why is this? I know there mucst be a easy reason for it.


When i build there is no error either.

difficult to see without looking at the geometries in editor. I see you use box brush - did you try to convert them to a solid mesh? And made sure you didn’t mix up (accidentially) additive and substractive brush types? Can’t think of much more atm. The brushes are great for basic level design, but for detailed walls, floor etc they sure have their limits.

Hi! Yes, I guess I have to convert them all to meshes soon, its just that we are not 100% sure that we want these proportions of the whole apartment so until then Ill keep BSPs. But yeah it definately could be some overlapping since the door openings are reductive BSPSs. But its not that the weird parts are, or look like they are reductive, but maybe it could be a error since the reductive BSPs are pretty close to the solid ones.

The “triangle” and “rectangle/triangle” on the wall os actually parts of the ceiling BSP in the 2nd picture and of the floor in the 1st. But the BSP itself does not look like that if I were to pull them out to have a look at them. An if I put them back the errors will disappear fro a while. Well, Ill keep looking and get back if I fint the solution.

Also, almost everything in my map are BSP even the doorframes and lists and so on - so when Im gonna convert (my 1st time doing so), what is a good way to do it without mixing everything up? I guess Ctrl+a is not a good option, but maybe to try to make meshes of bif parts, or maybe one room at a time

Before you experiment too much - make a backup of your project folder.

Then I’d convert some Brushes to meshes and see if that fixes the error. I wouldn’t CTRL+A or you have one solid mesh and can never change anything again. I’d try to group halfway reasonable structures (i.e. “left wall”, “left wall ornaments”, “left doorframe” etc), you can later make folders for “grouping them”, then you can just close all folders in the hirarchy if there’s too many objects around. The more brushes you combine into a mesh the less flexible it gets. I’d make a “Wall” the biggest combined brush object since you can easily copy/replicate them and you often come into a situation where you are like “nah the hallway has to be narrower” or “Dang the room needs to be deeper”, so you often move walls in a practical project.

Epic only recommends brushes for “prototyping” or just making a basic path for walking. You can use and abuse brushes a lot, but they might have some issues especially with overlapping stuff.