Pedestrian & Cyclist Path System

Overview

This system controls the movement of pedestrians and cyclists along defined paths in the scene. It is built from four cooperating components:

Component	Role
WaypointSystem	Defines an ordered sequence of path points
WaypointFollower	Moves a character along a WaypointSystem
HumanNpcSpawner	Pool-based spawner that assigns NPCs to unique paths
SpawnerOnWaypoint	Manual or timed spawner for individual scenario NPCs
ScenarioHumanId	Assigns a unique persistent ID to each spawned human

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WaypointSystem

This component should be added to a parent GameObject. Child Transform objects define the waypoint positions in sequence.

Setup

1. Create a parent GameObject (e.g., Path_Sidewalk_A).
2. Add child Transform objects at each waypoint position.
3. Add the WaypointSystem component to the parent.
4. Click Clear Waypoints, then Generate Waypoints from Children — this populates the list in order.

If Gizmos are enabled, the path is drawn as: - Cyan spheres at each waypoint - Green lines connecting consecutive waypoints - A closing line from last to first when loopStatus = true

Green line in the Scene view and WaypointSystem in the Inspector.

Key Properties and Methods

Member	Description
loopStatus	When true, GetNextWaypointIndex() wraps from last back to first
GetFirstWaypoint()	Returns the first waypoint Transform
GetClosestWaypoint(position)	Finds the nearest WaypointNode to a world position
GetClosestWaypointIndex(position)	Returns the index of the nearest waypoint
GetNextWaypointIndex(index)	Returns (index + 1) % count
GetWaypointByIndex(index)	Direct index access
GenerateWaypointsFromChildren()	Auto-populates the list from child transforms
EndPathCheck(index)	Returns true when index == count - 1

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WaypointFollower

By adding a WaypointFollower component to a pedestrian or cyclist, it will automatically navigate toward successive waypoints in the assigned WaypointSystem.

Assign the target path via the waypoint field in the Inspector.

Pedestrian NPC with a WaypointFollower component assigned.

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IConstraintWayPoint

IConstraintWayPoint is an interface for adding stopping conditions at specific waypoints — for example, stopping at a red light before crossing the road.

Constraint components are evaluated when the follower reaches the waypoint they are attached to, so place traffic-light constraints just before the crossing point.

Provided implementations:

Class	Description
ConstraintPedestrianTrafficLight	Stop when pedestrian signal is red
ConstraintCarTrafficLight	Stop when vehicle signal is red
ConstraintSaftyDistance	Stop when a vehicle is too close

Traffic light constraint attached to a waypoint before the crossing.

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HumanNpcSpawner

HumanNpcSpawner manages a pool of human NPCs and spawns them continuously throughout a simulation run. It is designed for crowd scenes where many pedestrians need to be maintained without manual placement.

Spawn Behaviour

1. On start, an initial burst of NPCs is spawned immediately.
2. A repeating coroutine spawns additional NPCs at random intervals within a configured range.
3. Before instantiating a new NPC, the spawner reuses any deactivated NPCs from the pool.
4. Each NPC is assigned to a unique WaypointSystem — two active NPCs never share the same path.

Fields

Field	Description
npcPrefab	Human NPC prefab to instantiate
waypointSystems	All available WaypointSystem paths
spawnCountVariance	Random variance applied to the spawn count per batch
spawnInterval	Time between spawn batches

Pool Reuse

When an NPC reaches the end of its path and deactivates, it is returned to the pool and becomes available for reassignment on the next spawn cycle.

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SpawnerOnWaypoint

SpawnerOnWaypoint is a lighter-weight spawner for scenario-specific pedestrian placements. It spawns a single NPC either on a key press or on a configurable timer, and assigns it to a specific WaypointSystem.

Fields

Field	Default	Description
spawnKey	KeyCode.O	Manual spawn key
useRandomTimer	false	Enable automatic timed spawning
minTime / maxTime	—	Random interval range for timed spawning
waypointSystem	—	Path the spawned NPC will follow
npcPrefab	—	NPC prefab to instantiate

Every NPC spawned by SpawnerOnWaypoint receives a unique ScenarioHumanId automatically.

Tip

Use SpawnerOnWaypoint when you need to trigger a pedestrian appearance at a specific scenario moment. Use HumanNpcSpawner when you want continuous background crowd generation.

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ScenarioHumanId

ScenarioHumanId assigns a globally unique sequential integer ID (as a string) to each human NPC. It is added automatically by both HumanNpcSpawner and SpawnerOnWaypoint.

Purpose

The ID is used by the LogArea system to uniquely identify each pedestrian across CSV rows, even if multiple pedestrians are in the scene at the same time.

Usage

var idComp = npc.GetComponent<ScenarioHumanId>();
idComp.AssignNewId();       // assigns the next available ID
string id = idComp.HumanId; // "0", "1", "2", ...

IDs are sequential and restart from 0 each time Unity enters Play mode. The DisallowMultipleComponent attribute ensures only one ID is assigned per NPC.