BSP Brush
We used the BSP Box Brush in Chapter 2, Creating Your First Level, extensively to create the ground and the walls.
BSP Brushes are the primary building blocks for level creation in the game development. They are used for quick prototyping levels like how we have used them in Chapter 2, Creating Your First Level.
In Unreal, BSP Brushes come in the form of primitives (box, sphere, and so on) and also predefined/custom shapes.
Background
BSP stands for binary space partitioning. The structure of a BSP tree allows spatial information to be accessed quickly for rendering, especially in 3D scenes made up of polygons. A scene is recursively divided into two, until each node of the BSP tree contains only polygons that can render in arbitrary order. A scene is rendered by traversing down the BSP tree from a given node (viewpoint).
Since a scene is divided using the BSP principle, placing objects in the level could be viewed as cutting into the BSP partitions in the scene. Geometry Brushes...