Testing Visibility with an Actor's Bounds
Each Actor placed in a Level has a set of bounds using a box and a sphere that is used for various things in the Engine. One of those being specifically to test whether an it is visible or not. The bounds of an Actor is made up of two parts: a sphere and a box. The bounding sphere is used for fast collision detection with a simple distance test, and, more often than not, it's greater in size than the object it contains. On the other hand, the bounding box is a closer match to the shape of the object and provides more accurate results.
Visualize bounds of Actors in the Level Viewport by selecting Show > Advanced > Bounds
. Alternatively, in the Skeletal Mesh Editor you can select Character > Bounds
and in the Static Mesh Editor, select Bounds
in the main toolbar.
An Actor with its bounds (sphere and box) displayed.
Each Static Mesh and Skeletal Mesh has its own bounding box and sphere that automatically scales to the size of the geometry when imported, or when scaled or rotated in the viewport.
You can edit an Actor's bounds using the following ways:
Increasing an Actor's bounds can potentially impact performance and shadow quality by keeping the Actor from be culled sooner than it would otherwise have been.