- A 3D modeling program like 3ds max, Maya or Blender to create models
- A 2D paint program like Photoshop or Gimp to create textures
- The Unreal Editor to assemble the pieces for your map and add the game play elements of the map.
If you don't feel the need to create custom models or textures yourself all you need is the Unreal Editor. However, we don't know yet which version of UE4 the community will get. Some members of the team feel like the editor we are using is too powerful and lets people do things and create maps that don't fit the game. So we might lock some features. We're also observing the free Unreal Tournament 2014 development, they might create a 3rd party level editor that we could use as well.