How to make a BSP brush invisible?


I am using BSP brushes as triggers for camera zones (think resident evil 1).
Obviously these BSP brushes need to be invisible at runtime, and also not show in the perspective view in the editor (although still having the wireframe visible would be great when using the orthographic views)

I don’t want to convert it to a blocking volume (at this stage) as i need to edit the vertices right up until the point the gameplay is finalised.

Is there any way of making them totally invisible but still generate overlap events… perhaps a totally invisible material?

Please could someone show me how to do this?

Many thanks,


Did you try Trigger volumes?

Invisible Material might work though. But I think setting them up as volumes is a better way to do it.


Thank you for your reply; however Trigger Volumes can only be Cubes, Spheres or Capsules. I need arbitary shapes which is why I was using BSP brushes with edited vertices.

Re: the invisible material; do you know how I can achieve this?


For invisible materials.

Create a new Material, Set lighting to ‘Unlit’.Create a float constant, set it to 0. Now connect this to Opacity node.

Now drag this material on top of your brush.

But I believe there are more proper methods to achieve what you want. I will look into it when I get time.

Great, thank you. I shall try this (the invisible material) method when I get home tonight.
This will do for now for prototyping the game.

Regarding any better method, then that would be fantastic if you find one… thank you!


Going to answer my own question now!

Thanks to mindfane, I investigated Trigger Volumes.

I didn’t realise that Trigger Volumes they can have their vertices modified in the same manner as brushes (I thought that we were stuck with the original shape)… so, for me at least, I no longer need to make brushes invisible, and Trigger Volumes give me exactly what I need!

Cheers mindfane! :slight_smile:

Great. You found the answer yourself.
I knew we could have volumes in any shape in UDK. So its still UE4 as well. great!


While I do realize that this question is almost three years old now, I would just like to add extra help for those that had the same problem as me - make custom shaped collisions i Unreal.

While this is entirely possible to do in a 3D-modeling application, such as Autodesk maya, it is also possible by using addative and subtractive brushes in Unreal.

Just make sure to select all brushes before pressing the create static mesh in the brush settings panel in the
details window.