You can implement picking if it ' s important to you to trigger whatever the player is looking at , if you only want to trigger something the player is near and don ' t care if they ' re looking the opposite direction , implement what ' s called a trigger area . It ' s essentially just a larger bounding box or sphere since that ' s faster . You can either trigger the action automatically when they intersect with the trigger area , or make it so if they ' re intersecting AND pressing ' A ' you trigger an action , etc . The action can be an event broadcast or tied directly to the box , or whatever . Otherwise you have to implement picking , and there is a lot of information about implementing picking available . One way I ' ve done picking in the past it to render an additional buffer with an encoded entity ID during the geometry pass of a deferred renderer . Afterward you can read the RGB value of that buffer at the pixel where the crosshair is and decode it into an Entity id to figure out what entity should be picked . I ' ve never actually read any picking implementations so this is probably a terrible way of doing it . In my case it was for a world editor so being pixel perfect where the mouse pointer was , was important .