Game Development Reference
Can I use static meshes to create my map without using BSP?
Yes. Although, you will need a 3D sotware applicaion that supports UDK's plug-in, such as
Autodesk Maya, 3Ds Max, XSI.
UDK CSG Operaions for Brushes include the following:
Dominance of static meshes
Staic meshes are simply the models in your level. If you open up any UDK map, 90 percent
of the map will be staic meshes and the rest will be BSP brushes.