it makes you entity atached to your camera invisible for the camera

i search it up for you

view.genius
Player entity that is attached to the view. Used for first person and third person games. This entity will be invisible if the view is within its bounds. All entities that have their parent pointer set to the genius will then be invisible also. If the view is outside the entities' bounds, the entity and its childs become visible, but any object outside the entities visibility range is suppressed by the BSP tree process. By setting GENIUS to NULL, no entity is attached to the view.
Type:
ENTITY*
Example:
camera.genius = me; // current entity invisible inside view range