Will using only 1/4 of a BSP cylinder cause issues?

Hi Guys!

I am recreating a swimming pool. And I am making some stairs. I though making them out of cylinders would work. However, I am wondering if there is a problem in making a cylinder and only using 1/4 by just placing it like the picture, or if I should cut out the part’s I don’t need from it. And if so, how do I cut down the brush so I only keep a quarter of it.



Thanks guys

Hi Motanum,

There is nothing wrong with using the cylinder the way you are. If you would like to ‘cut’ the extra off, you could always do that with a couple of BSP boxes that are using Subtractive geometry instead of Additive.

However, I wouldn’t worry about it to much because BSP are made for blocking out a level (a placeholder) and should be swapped out for imported models before the game is finished. This is because BSP’s are performance heavy. If you have a finished game with any BSP’s geometry you are going to notice a major loss in FPS.

Thanks, TJ

Okay, thanks.

The problem I have with this is that I come from the Source Engine, where brushes are our main tool and are also used to limit visibility and optimize levels. So, I keep wondering how you optimize levels in UE4 so that stuff behind a wall is not visible for example.

If you know some tutorials that can be handy, I’d appreciate it links.


I haven’t used the Source engine in some years, but after some research I see what you are talking about now.

UE4 doesn’t cull the back sides of BSP geometry or static meshes for you. How to achieve this is to model your assets with this in mind. A good rule of thumb is if you aren’t going to see the geometry, then it shouldn’t be there.

Here is some links to help you find more info:

Another great place to start is our Wiki tutorials and videos:

I hope that helps, TJ