BSP extrude problem


I have a little problem with extruding a hollowed cube.

As you can see on the picture, I can extrude the outer wall without problems, but when I try to extrude the inner wall, I can just move it to the blue points. I know why it doesn’t work, but I don’t know how to get it work ^^. Has anybody any suggestions?

Hi Philip,

There may be a few workarounds. One is that the translation tool cannot be grabbed through bsp walls, so moving it from within may help. Also if you can extrude that wall at all, can you extrude it a little, then switch to Edit and just move it the rest of the way? You said you knew what was causing it, could you please explain that? I may need to report it. I hope that this has helped.

Thank you,


Thank you for your answer, but it isn’t working.

“You said you knew what was causing it, could you please explain that?”

The problem are the vertices from the outer wall (those which I marked with the blue circles). I just can move the extruded part of the inner wall to those vertices, but not further. There is the problem. I need to pass through those vertices to get what I want (-> a turnoff)

Hey Philipp,

It is unfortunate that the potential work around had no effect. Another option may be to create the BSP then add another subtractive volume where you want the hall for now.

I have compared this issue with Beta3 versus an internal build and it would appear that BSP editing is completely different. This issue will be resolved in a future release of Rocket.

Thank you,

Ok, nice to know. Then I will do it with the “UDK hollow” variant ^^ Thank you for your support.