Unreal has several collision filtering channels pertaining to different Object types (vision, weapons projectiles, players, static meshes , etc etc)
An object can be set to interact with other objects on the relevant channels in one of three ways :
- Ignore : any collision with other objects of this channel are ignored by the object in question
- Overlap : allows other object on channel to overlap or pass through but still triggering a collision event
- Block : Doesn’t allow the colliding objects to pass.
For each of the above to work both colliding objects must have the same settings otherwise the lower collision option is taken (for example Ignore vs Overlap would result in Ignore even if one of the two colliding objects was set to overlap.
Furthermore the collision bounding box can be either simple or complex(taken directly from geometry) as needed