How to make a triangle shape floor?

I’ve tried taking the normal box floor rotating it 45 degrees and cutting it in half. however…
couldn’t find a way to cut the floor in half.

You could use an external program like Blender to create your own floor mesh.

Do I need to use an external program to create a simple triangle shape? sounds weird…

Are you using BSP to make your floor? I’m not sure how (or if) BSP handles non-quad shapes. I’d recommend making a static mesh in a 3D modeling program, such as Blender or Maya. Then import it as a Static Mesh into the engine. You’ll then be able to scale the mesh to fit your needs.

Here’s the documentation page on BSP: Geometry Brush Actors

BSP is primarily used for blocking out a level during prototyping and early design. In a final level, you would usually replace nearly all BSP with Static Mesh Actors instead; primarily for performance reasons, but also, you can create infinitely more complex geometry with static meshes then you can with BSP.

I’m quit new to the engine so I had to check what BSP means and If it means creating a 3d object (like a pyramid) then this is not what I ment.


There is not a Geometry/BSP brush in the engine by default. But you can take the square and use a subtractive brush to get rid of side. The thing with this though is that these two meshes need to stay in this position because the subtractive is not directly attached to the original box brush.

You can see from my image how this is. The blue vert box is the additive brush meaning it will be visible in the level. The rose/red colored verts are the subtractive brush. These will cut away at any other BSP/Geometry objects. It will not work with normal static meshes imported form a 3d modeling software.

Do I need to use an external program
to create a simple triangle shape?
sounds weird…

This is standard in games. These days 99.9% of all games are built using static meshes made in a 3d modeling software. For Epic, BSP/Geometry objects are used to primarily block out and prototype a level before being handed off to 3d artists to build the meshes that will ultimately populate the levels.

Epic uses Maya and 3Ds Max for all of it’s mesh creation for use in UE4.

If you have any questions feel free to ask! :slight_smile:


Thanks for the clarification Tim. Having to use two static meshes makes a lot more sense now.
And thank Fluppi393 and Jonathan as well. the community here is amazing

Took a bit of playing around, but I think I have the “right” answer, as far how to create a flat 3D triangle. Hopefully this helps someone in the future (sorry to resurrect a zombie post)

  1. Start with your cube. Adjust your z-axis to the height you’re looking for.

  2. In geometry “Edit” mode, select the top face and hit “Triangulate”. This will split your cube down the middle.


  1. Choose one of the pair of vertices that aren’t connected to the splitting line, then press delete.

  1. You will now have a triangle with a “missing” face. If you don’t need that face, you’re done.

  1. In clockwise order, select the four vertices of the “missing” face.

  1. Hit “Create”. This will create a polygon to fill in that space.

  1. You’re done