Search in
Sort by:

Question Status:

Search help

  • Simple searches use one or more words. Separate the words with spaces (cat dog) to search cat,dog or both. Separate the words with plus signs (cat +dog) to search for items that may contain cat but must contain dog.
  • You can further refine your search on the search results page, where you can search by keywords, author, topic. These can be combined with each other. Examples
    • cat dog --matches anything with cat,dog or both
    • cat +dog --searches for cat +dog where dog is a mandatory term
    • cat -dog -- searches for cat excluding any result containing dog
    • [cats] —will restrict your search to results with topic named "cats"
    • [cats] [dogs] —will restrict your search to results with both topics, "cats", and "dogs"

Office Holiday

Epic Games' offices will be on holiday from June 22nd to July 7th. During this period support will be limited. Our offices will reopen on Monday, July 8th. 

How to work efficiently using BSP?


I have a question regarding building a level using BSP. I'm quite new to level design and I'm trying to build a simple tutorial, consisting of a few "chambers" (similar to Portal).

When I started building the level for the first time I created a cube, made it hollow and deleted the external faces. That way, I thought, it would be a lot easier, because I could see the inside of a corridor while being outside of it. Then I started extruding the cube to create the corridors. Sadly, during developement a few problem have arisen. Mainly - I couldn't create additive shapes outside of the chambers (they were invisible; meanwhile subtractive shapes carved holes in the air) and the editor started crashing. It looks like I broke something :/

So I decided to do it another way. I started building the level using modular pieces. Every wall, ceiling, etc. became a seperate cube.

alt text

This took me a LOT more time to create and I can't look at my level from the outside, but this time nothing was broken, at least.

So now I'd like to ask - what's the best way to work with BSP. Is it one of the techniques I used? If not, what method should I use to create my level?

Product Version: UE 4.7
a.png (963.7 kB)
more ▼

asked May 18 '15 at 08:21 PM in Using UE4

avatar image

85 14 16 95

(comments are locked)
10|2000 characters needed characters left
Viewable by all users

1 answer: sort voted first

Hi Bproof,

Your first method should work but you may be using add / subtract BSPs incorrectly. When you're placing add / subtract BSPs, they are put in a stack. The most recent BSP will override the ones before it. This means if you place an additive Cube BSP, then a subtractive Cube BSP that intersects it, it will subtract part of the BSP. If you put another additive Cube BSP that is intersecting the subtractive one you just placed, it will not be subtracted from. I don't know of a way to reorder BSPs once they have been placed, so deleting and re-adding would be the only method.

I hope this helps. If you still need help, please let me know.

Matthew Clark

more ▼

answered May 18 '15 at 09:02 PM

avatar image Bproof May 19 '15 at 08:40 AM

Hi, thank you for the reply!

So, just to clarify - are you telling me that building a level out of little pieces is not the way to go? And how would you go about creating a corridor? Would you create a hollow cube and delete the exterior faces? Or would you just flip the cube to create a room?

avatar image Matthew J May 19 '15 at 03:38 PM

A lot of this is based off preference and which workflow works better for you. I personally would do it all as separate pieces so that if I changed my mind later on, it'd be much easier to move things around than to mess with how the add/subtract BSPs stack. It's also easier to attach meshes to single objects instead of trying to attach multiple meshes to one big object.

avatar image Matthew J May 26 '15 at 01:44 PM

Is there anything else you require information about? In the meantime, I'll be marking this question as resolved for tracking purposes. Feel free to comment and the question will reopen.

avatar image ambhar Sep 04 '15 at 05:41 AM

Working with BSPs is having any impact on performance compared to static meshes? And if yes then why and when and where should we use BSP and static meshes?

avatar image Matthew J Sep 04 '15 at 01:42 PM

Hello ambhar,

BSPs are less optimized than Static Meshes. BSPs are normally very useful for prototyping and setting up the initial parts of a level. It would be best to replace all BSPs before finishing development, which can easily be done with the conversion tool.

(comments are locked)
10|2000 characters needed characters left
Viewable by all users
Your answer
toggle preview:

Up to 5 attachments (including images) can be used with a maximum of 5.2 MB each and 5.2 MB total.

Follow this question

Once you sign in you will be able to subscribe for any updates here

Answers to this question