Yggdrasil WoW makes NPCs move in smooth curves instead of sharp corners

Yggdrasil WoW changed how every NPC on the realm moves on 22 September 2026. Creatures now sweep through the corners of their path in arcs instead of turning sharply at each point.

Why NPCs walked in polygons

Private servers usually build a creature's path from A to B out of straight lines across the map, adding extra points wherever it would hit a wall or an object. An NPC patrolling past a building ends up tracing its walls in short straight lines, a pentagon pretending to be a circle, as the team put it.

The fix is Catmull-Rom pathing, where the server sends the client what it needs to draw each corner as an arc. That alone is not enough, because the client also uses a value called movementId to know how fast each creature turns, anywhere from 0.25 to 10 radians per second. That value only came with Wrath of the Lich King, and few creatures have a known one, so Yggdrasil gives every creature without one the most common rate, 10 radians per second.

The result

• Patrols, chases and other moves curve through their corners
• Each arc fits that NPC's turn rate: slow turners swing wide, fast turners stay tight
• Every arc is checked against line of sight and ground height, so a curve that would cut through a wall or float in the air is sent as a plain corner

The changes are public in the server's core on GitHub.

Sources: Yggdrasil WoW news post "Development update" (22 September 2026).