Request: BSP Improvements


I’m enjoying using Unreal Engine 4, however after some extended use I feel that the BSP tools could be improved compared to the rest of the feature set. Here’s a few specific issues I have encountered when using them to block out levels:

  • With the “Update BSP Automatically” setting on: freezing when editing or adding brushes in a map containing around 50, and long freezing when CTRL + Z’ing changes (I realize while the number of brushes increases, the calculation time becomes greater, but freezing for over 10 seconds is unworkable)
  • Resizing faces results in unexpected behavior:
  • (could be a training issue on my part)- Brush origins often get offset from geometry, have to be manually moved back (an auto-reset to median point feature would be nice):
  • Crashes to desktop when using BSP tools (I’m not able to cite any causes for these, they seem completely erroneous. During an hour of work UE4 generally crashes around 5 times, but only when using BSP tools - it’s stable with everything else. I always submit crash dumps for these.)

Aside from that, they’re extremely powerful blocking out tools. Subtractive brushes are especially cool :slight_smile:


I am also seeing crashes with brushes (I think the term BSP is a misnomer and should be avoided, brush/csg is more accurate); I think my crashes are actually when using CTRL+Z after doing various brush manipulation.

Here are some things to add to the list (unless I am simply doing something wrong, in which case please tell me):

  • Cannot create a working Blueprint from brushes; creates an empty BP and replaces your selected brushes with the empty BP!
  • Transform is not exposed so its difficult to line things up or build to strict coordinate/size guidelines
  • Should be an option to cook all brushes to static meshes (assuming there is actually a performance benefit based on other posts on perf related to brushes)

Other issues/bugs that hurt usability:

  • When creating a static mesh from multiple selected brushes, if a folder is also selected the static mesh will be empty
  • When creating a static mesh the brushes are replaced, this should be optional as the brushes are lost at this point unless map is backed up or reloaded without being saved
  • Brush properties such as shape, hollow, etc. should be hidden once a brush has been modified beyond these meanings (i.e. a box re-shaped to a wedge should not show box, or let you change to another primitive shape without warning); changing this after the fact causes loss of work (brush is reset)

Cool, cheers. I’ll add the points to the OP if the thread gets any bigger. Not sure how many of mine are me doing something wrong either, but I guess either way it’s good feedback for the team :slight_smile:

Hi AlanEdwardes,

There are some known stability issues with BSP/Geometry brushes. The are primarily used for blocking out levels as you’ve indicated. We do have on our Trello UE4 Roadmap
for BSP/Geometry brushes to get an overhaul. It’s currently on the Backlog/Wishlist and will be addressed at some point in the future but is not currently planned.

Thank you!


Okay, thanks Tim. I’m sorry to hear that it’s not planned, but at least it’s recognized as an area needing attention.