BSP Surface Render Issue

Hi Folks,

Recently I’ve started using UE4 a bit more, I downloaded the ShooterGame project just to see how one can go about in learning the specifics of weapons, pickups and FPS animations etc. With this in mind I decided to create a simple test level to test my new weapon and pickups out in, making this level I just used some simple BSP boxes, some additive and others subtractive, to just block out a testing area for my content. Finished the small level and used some of the materials that came with the ShooterGame Example.

I rebuilt both the Level geometry and lighting for the level, and once this was complete, the following happened. I’m still not sure what is causing this, but the surfaces seem to render incorrectly and tend to jitter whenever the camera moves, at first I thought it might have been the material, replaced it with another, and it seemed to persist, don’t have any double meshes on each other or anything that might cause two materials to overlap or anything.

Anyone know what might be causing this? It only seems to happen on this level, haven’t seen this happen anywhere else.

If it helps, I’m currently running the latest NVidia Drivers for my Graphics card.

System Spec:

OS: Windows 7 Ultimate 64-bit
CPU: Intel I5 3330 @3.0 ghz
RAM: 8gb
Graphics: NVidia GTX 660 Ti 2gb

Hi Xelus,

Thank you for your report. I am looking into this issue and I was not able to get it to reproduce on my computer. I may need some more information from you to narrow down the possibilities a bit. The most important things to know right now are:

  1. What version of the engine are you running?

  2. Do you see this issue when you play one of the levels included with shootergame? (Sanctuary, High Rise)

  3. Do you see this issue if you create a new blank project?

Hopefully with this additional information we will be able to work out this issue for you. If there is anything else that you think would be helpful feel free to include that info as well. We can never have too much information.


Hi ,

To answer your questions:

  1. At the time of creating this simple map I’m using version 4.7.0 of UE4 (Busy downloading version 4.7.2, will see if the problem still occurs)

  2. I haven’t experienced the issue in any other level, I did notice however, that deleting the BSP block and re-adding it seems to fix the problem temporarily, after which, a few minutes later the bsp starts doing it once again.

  3. I made a different test map before this one, and never had the issue. If it helps, when I started using subtractive BSP the problem started to occur, with each subtractive BSP, the problem seems to have gotten worse. Also, it doesn’t seem to happen on all of the surfaces, for instance, the holes in the ceiling, their walls are fine, however, the floor and the ceiling surfaces seem to react the most to the issue. It looks as if though most notably, horizontal surfaces get affected the most.

The doorways also seem to be fine. If it helps, I noticed when replacing the bsp, before it starts to occur again, the textures become fuzzy and start to jitter around whenever the camera moves, and eventually end up with the bsp stretching the texture so much that it appears as a single color, setting the surface properties back to 1 for the texture, doesn’t seem to restore the textures coordinates.

Also noticed, that especially the floor, seems to be rotating the real-time reflection from the material, to 45 degrees, as if the surface is somehow angled rather than being perfectly flat which the physical BSP actually is.

This happens both in the editor as well as running the map in-game. Walls start off fine, but once I spawn and fire a shot, the wall bsp seems to the same as the floor and ceiling, not as bad, but still noticable, however wall reflection stay un-affected by the visual bug.

Once my download is complete, I would be able to provide you with more screenshots if the problem still occurs in version 4.7.2

Hope it helps.

Kind Regards

Hey Xelus,

I’ve been digging into this issue a little further for you and I have managed to reproduce the issue that you are seeing. I do not have exact reproductions steps ironed out quite yet, but I was able to gather enough information to put together a bug report which I have submitted to the developers. The Jira ticket number is UE-11375. I will keep an eye on it and let you know when progress has been made.

Side note: I am still working on this issue and will add more info as I find it so if you see anything useful just post it as a comment and I will add it to the ticket.

Thanks for your patience while we work out this issue,


Thank you very much for the help. Much appreciated. I’ll check the map on the updated engine, and if the issue is still present, I’ll send some screenshots your way to hopefully help understand what happens with the visual bug, and maybe a short video clip to see the bug happening.


So I followed up on the issue on 4.7.2, and is still present, so I thought I’d send some screenshots for you, it seems as if though the bug has gotten a slight bit worse on the ceiling and walls, however the floor seemed to be a slight bit less affected by it, though it still has the fuzzy jittering texture.

Hope these can help out and give more info on what happens. I’m including a map overview, as well as where the bug is happening and the fuzzy material on the surface of the BSP floor. Let me know if there is anything else you need.

Fuzzy Jittering Floor material

Ceiling Hole wall texture unaffected

Wall surface stretched

Map Overview of BSP map

Hi Xelus,

Thank you for the additional info. I have added it to the ticket. I’ll keep you posted on progress.