So I was making a level, placing some props, and I tried to build and it said that the PlayerStart was unusable, then I noticed that the add mode wasn’t working on brushes, only subtract, so i decided to make a huge brush and subtracted, and sure enough, i have a load of surfaces surrounding my level. I thought ‘well it doesn’t matter, they’re outside my skydome anyway, won’t cause any problems’, but now building doesn’t work, it just crashes udk. The textures on the surfaces flicker in and out so I assume they are right at the edge of my map. I used the ‘Clean BSP Materials’ thing and it didn’t do anything.
There is a picture attatched if it helps, I hope someone can get back to me on this because it has taken ages to make this level. I have a feeling I may have accidentally switched the map to subtractive mode, but I don’t see how that could have happened.