Testing Visibility with an Actor's Bounds
Each Actor placed in a Level has a bounding area 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 with 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 it's 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 the bounds of an Actor in a couple of ways:
Increasing the bounds of an Actor can affect performance and shadow quality by keeping it rendered longer than needed.