AI roaming

Monsters that wander or patrol, attack on sight, fight back, chase, and run home invulnerable when pulled too far. Two components do this, and both come from checkboxes on the unit definition.

Setup

On the monster’s unit definition:

Field	Meaning
Use Hostile AI	Attack hostile units that come inside Aggro Range, and fight back when something targets this unit through threat or a taunt. Attaches `VtHostileAi`.
Aggro Range	Notice radius in world units. 0 never engages on sight.
Roam Radius	Wander this far from home between idle pauses. 0 stands still. Attaches `VtRoaming`.
Leash Radius	Distance from home at which the unit drops the fight and runs home. 0 disables the leash.
Roam Idle Min / Max Seconds	Pause between walks.
Roam Speed Multiplier	Wander speed relative to move speed.
Return Speed Multiplier	Sprint speed while returning.

Leave both boxes off for players, NPCs and anything passive.

stateDiagram-v2
    Idle --> Walking: idle timer ends
    Walking --> Idle: arrived
    Idle --> InCombat: target acquired
    Walking --> InCombat: target acquired
    InCombat --> Idle: target lost
    InCombat --> Returning: past leash radius
    Returning --> Idle: reached home

While returning the unit is invulnerable, cannot be targeted, drops its threat table, and ignores everything until it is home. OnStateChanged fires on every transition, which is where an “evade” emote belongs.

Walking around obstacles

Give the monster prefab the same two components the player has: VtTopDownClickToMove and VtNavMeshPathProvider. Wandering, chasing and returning then go through the mover and use the baked NavMesh. Without them the unit steps straight toward its destination, which is fine for open ground.

Patrol routes

Create an empty GameObject, add Vantage → AI → VtPatrolRoute, and put an empty child object at each waypoint. Children are used in order; drag transforms into Waypoints to override. Loop walks the route in a circle, off walks it back and forth. The route draws in the Scene view.
Assign it to Patrol Route on the VtMobSpawner that spawns the monster, or set roaming.PatrolRoute from code.

The unit walks the waypoints with the usual idle pause between them. Set the pause to 0 for a continuous patrol. Home follows the route, so the leash is measured from the last waypoint reached rather than from the spawn point.

Which units fight

Units of different factions attack each other unless either one is Neutral. Neutral units are never attacked on sight and never attack. The rule is VtFactionRules.AreHostile if you need it in your own code.

Runtime

var roaming = unit.GetComponent<VtRoaming>();
roaming.State;
roaming.Home;
roaming.SetHome(anchor);
roaming.PatrolRoute = route;
roaming.OnStateChanged += (from, to) => { };

var ai = unit.GetComponent<VtHostileAi>();
ai.scanInterval = 0.5f;
ai.lineOfSightMask = wallsLayer;      // empty = notices through walls
ai.OnTargetAcquired += target => { };
ai.FindNearestHostile();

Hostile AI scans only while it has no target. An engaged unit costs nothing per frame beyond keeping its basic attack armed.

Your own AI

Subclass VtRoaming and override StepTowards to change how a unit without a mover moves, or replace both components with your own and reuse the pieces they are built from: VtCombatEngagement.SetTarget, VtUnitAbilities.SetAutoCast, VtUnit.SetInvulnerable and VtThreatTable.Reset.