In ABx a Player or NPC can move autonomously from one point to another. For example, a Player can click on a point on the Terrain, the client calculates where the mouse pointer hits the terrain with a raycast and tells the server to move to this coordinate.
To make this happen, the server performs three steps: (1) Find a path to the destination, (2) avoid obstacles on this path and (3) if there is some dynamic object on the way the actor would collide with, slide along the bounding box of this object. Also NPCs use the same method …