Two physics fixes that have been a long time coming. Spotted by Ashley walking past a bear levitating in a field.
NPCs stay on the ground
Monsters now snap to terrain every movement tick, not just when they happen to start within a metre of it. The result:
- No more floating bears, levitating wolves, or hovering bandits. If you spotted one of the persistent floaters in Halcyona or the Dewstone Plains, they'll be on the dirt next time they respawn.
- No more underground spawns. If a spawn point's coordinates had drifted below the heightmap, the NPC would just live there forever, untargetable. Fixed.
- If you run upstairs in a building, the monster chasing you stays on the ground floor instead of rising vertically to phase into the room you ran to. They'll still try to walk straight at you in XY (so they'll bump against the wall under your feet), but the bear will not appear inside your bedroom on the second floor.
What this does not fix: the monster will still walk through the wall in XY trying to reach you. AAEmu has no building collision in its chase code — and adding it is a much bigger project (a navmesh or per-zone waypoint graph) that's not happening tonight. For now: going upstairs is a real escape; the NPC will leash out within 50m.
The technical cause was a 1-metre tolerance gate in two places (NpcSpawnerNpc.cs at spawn, Npc.cs per movement tick). The gate meant terrain-snap only applied if the NPC was already within 1m of the ground. Once it drifted further — chasing a player off a cliff, spawning on a sloped JSON coordinate, or rising to match a player's Z on an upper floor — it could never recover. Both gates are gone; NPCs snap to heightmap whenever terrain data is available.
Leash teleport-hop is no longer a hop
When you outran an aggro'd monster past 50 metres and it gave up chasing, it would visibly zoom back to its spawn point like it was being yanked on a fishing line — a clearly-broken-looking animation hop. That's fixed; the leash return is now an instant clean snap-back, no high-velocity sprint animation in between.
Upstream was sending two contradictory packets on the leash event — "I just ran 1,000,000 units in one tick" followed by "actually I'm standing still" — and clients tried to animate the impossible run. We now send only the second packet.
What's still on the floor (not fixed yet)
- Monsters walking through walls. XY pathing is still straight-line lerp. They will path-into walls, doors, and your house's front porch.
- Monsters not using stairs. Same root cause — there's no navmesh.
- **Teleport-hop toward you** (the one Ashley reported separately from the leash-back hop). Different code path; needs its own investigation. If you see it, ping the dev channel with the zone and the mob name.
Behind the scenes
Three server-source patches: NpcSpawnerNpc.cs, Npc.cs, ReturnStateBehavior.cs. All tagged // Rookery fix 2026-05-23: so they survive future upstream pulls. Memory inventory in reference_aaemu_3_local_patches.md entries #15 and #16. No client patch — the launcher will see the same .pak and skip the download.