ABSTRACT
On Assassin's Creed Syndicate, part of the mandate for the AI team was to support horse-drawn carriages at every level for the nonplayer characters (NPCs). This chapter adapts the NPCs' steering behaviors to navigate around a convex hull representing the vehicles instead of using a traditional radius-based avoidance. Most object avoidance steering behaviors are implemented by avoiding circles or ellipses. Classical obstacle avoidance provides an agent with a lateral pushing force and a braking force, allowing the agent to reorient itself and clear obstacles without bumping into them. To mitigate the wide avoidance paths, the circular obstacles are modified into ellipses. The best representation of the vehicle we could conceive was a convex hull, as it could wrap around all of the subparts of the vehicle without creating any concave sections. This would allow the NPC to steer against the horse-drawn carriage as if it were a single uniform obstacle.
