Skip to content

Adding a new Pedestrians

Entry point into Evacu-agent logic from Traffic3D

The entry point that initiates Evacu-agent logic in Traffic3D can be found in PedestrianFactory.

The method SpawnPedestrian() instantiates a regular Traffic3D pedestrian consisting of:

  1. A humanoid pedestrian model.
  2. Walking and running animations.
  3. Textures for clothing and facial features.
  4. A Pedestrian script.

The Pedestrian script for Traffic3D allows Pedestrians to spawn and then walk or run to a randomly chosen junction.

Upon reaching the road junction they have chosen to cross, the Pedestrian will wait for the appropriate traffic light signal to cross.

After crossing the pedestrian walks to a location and de-spawns.

Evacu-agent logic is then added to the Traffic3D pedestrian and the boolean isUsingEvacuationBehaviour in Pedestrian set to true to turn off Traffic3D pedestrian behaviour so the two sets of logic do not interfere.

Pedestrian types

Pedestrians are divided into Types.

For example:

  1. FriendGroupLeaderPedestrian.
  2. FriendGroupFollowerPedestrian.

Each different type models different pedestrians you may see in a high street setting.

The examples above model friend groups who will meet in a location on the map and then travel to various BuildingPedestrianPointTypeBase together.

BuildingPedestrianPointTypeBase are explained in more detail below.

Note the naming convention suffixes:

  1. LeaderPedestrian.
  2. FollowerPedestrian.

This is used as all pedestrians in Evacu-agent are in groups, with a group leader and followers.

Groups are explained in more detail below.

Points of interest on the map for Pedestrians

BuildingPedestrianPointTypeBase are places on the map to act as markers for buildings such as food stores and offices.

BuildingPedestrianPointTypeBase extends PedestrianPoint found in Traffic3D with specific types such as ShoppingPedestrianPoint extending BuildingPedestrianPointTypeBase.


All pedestrian types in Evacu-agent are in groups, which must contain one or more pedestrians.

Group logic is contained in GroupCollection.cs which is responsible for maintaining a List<EvacuAgentPedestrianBase> to represent the members of the group as well as storing the groups List<Vector3> path and Vector3 GroupDestination.

Only one GroupCollection is held by a group, and is placed on the group leader, with members receiving a reference to it.

By having only one GroupCollection per group the group is able to share the same path and path without updating many GroupCollection objects.

Pedestrians simply check the current destination in GroupCollection and make decisions from it, updating it when the currentDestination is reached.

GroupCollection is also used in grouping boid behaviours where pedestrians should apply different spacing behaviour to members of their own group than to members of other groups.

Boid grouping can be viewed in more detail on Boid Grouping.

Adding a new Pedestrian type

Several parts are needed to add a new Pedestrian into Evacu-agent.

The necessary steps have been listed below and then explained in more detail in subsequent lists.

Parts necessary:

  1. Add a new Pedestrain prefab.
  2. Create a new Pedestrian script.
  3. Create a new BehaviourTypeOrder.
  4. Create a new Pedestrian highlight.
  5. Add the necessary scripts to the new Pedestrian GameObject and set the appropriate values in the Inspector window.
  6. Add a AbstractEvacuAgentPedestrianFactory to instantiate the Pedestrian at run time.
  7. Add the new factory to PedestrianFactory.

1. Adding a new Pedestrian prefab object

Creating a prefab for each type of Pedestrian allows AbstractEvacuAgentPedestrianFactory to instantiate them at runtime without large amounts of code.

  1. Create an empty GameObject in any scene by right-clicking the Hierarchy, an appropriate name suffixed with LeaderPedestrian or FollowerPedestrian should be chosen. Creating empty GameObject example
  2. Drag and drop the new GameObject into Asset/Resources/EvacuAgent/Prefabs/Pedestrian_Types from the hierarchy window. Drag and drop of new prefab before Drag and drop of new prefab after
  3. Double click the new Pedestrian GameObject to open the prefab menu and ensure that each Transform component is set to 0 and that each Scale is set to 1 in the Inspector window. New pedestrian transform example

2. Create a new Pedestrian script

Creating new scripts for each Pedestrian has a similar benefit to creating prefabs of each pedestrian in that each can share a large number of properties through extending EvacuAgentPedestrianBase.

  1. Navigate to Assets/Scripts/EvacuAgent/PedestrianTypes in the Project window, right click inside the PedestrianTypes folder and create a new C# script. Creating a new Pedestrian script example
  2. Double click the script to open it in your IDE and set the script to extend NonShooterPedestrian. New Pedestrian script example
  3. If creating a group leader Pedestrian you will also need to create a path creator script in Assets/Scripts/EvacuAgent/PathGenerators that should extend NonShooterPedestrianPointPathCreator.
  4. The logic for the new path creator can utilise both PedestrianPoint locations or random valid locations on the NavMesh.
  5. WorkerPedestrianPointPathCreator is shown as an example below, it simulates a Pedestrian walking to work with a random chance of stopping for coffee before work.
  6. Only group leaders decide on paths for the group currently so non-leader group members do not require a path creator script.
public class WorkerPedestrianPointPathCreator : NonShooterPedestrianPointPathCreator
    public override List<Vector3> CreatePath()
        List<Vector3> path = new List<Vector3>();

        if (UnityEngine.Random.value < EvacuAgentSceneParamaters.WORKER_CHANCE_TO_VISIT_HOSPITALITY_POINT_IN_ROUTE)


        return path;

3. Create a new behaviour type order

  1. See Behaviour structure.

4. Create Pedestrian highlight

Each Pedestrian is given a highlight, modelled by a small flat circle that appears at the base of the pedestrian feet. This can be toggled by the UI at runtime to more easily distinguish Pedestrian types.

  1. Create a new empty GameObject the same as in Step 1 with the name prefixed with the pedestrian type and suffixed with the word Highlight. For example: ExampleLeaderHighlight.
  2. This new GameObject should be dragged into Asset/Resources/EvacuAgent/Prefabs/Pedestrian_Highlights.
  3. Create a new Material by right-clicking in Asset/Resources/EvacuAgent/Materials. New material example
  4. Change the colour of the new material via the Albedo property, the colour scheme is a darker shade of the same colour for leaders and a lighter shade of the same colour for non-leader members. New material colour example
  5. Open the prefab for the new highlight created in Step 4.2 and apply the material created in Step 4.4 in the material property of the Mesh Renderer, shown in red below. This change should be reflected in the shader property marked in blue. Setting highlight material example
  6. Add a tag to the highlight following a naming pattern of: PedestrianType Highlight. For example: exampleHighlight. Note that adding a tag will not apply it to the currently open prefab, a new tag must be created and then manually applied to the new highlight prefab. Add tag to highlight example
  7. Add a string value to EvacuAgentSceneParamaters that matches the string input for the new tag (case-sensitive). For example: public static string EXAMPLE_HIGHLIGHT = "exampleHighlight";.

5. Add the necessary scripts to the new Pedestrian

  1. Open the new pedestrian prefab again with the Inspector window open.
  2. Using the Add Component button add the pedestrian script created in step 2. Empty example Pedestrian prefab
  3. Populate the Pedestrian script as seen below remembering that non-leader group members do not require a Pedestrian Point Path Creator or GroupCollection. Scripts must be added via Add component and then dragged to the appropriate slot, prefabs can simply be dragged to the appropriate slot. Example Pedestrian inspector setup
  4. Please note that BehaviourStrategy scripts and BoidComponent scripts also need to be added via Add Component here but have been omitted for brevity.
  5. Add a new tag such as example and apply it to the new Pedestrian prefab.
  6. Add the same string used in the new pedestrian tag to EvacuAgentSceneParamaters for example public static string EXAMPLE_TAG = "example";.

6. Add a factory to instantiate the pedestrian

  1. Add a new script to Asset/Scripts/EvacuAgent/Factories with the naming convention PedestrianType LeaderFollowerPedestrianFactory. Add Pedestrian factory example
  2. Open the new factory script in your IDE and make it extend AbstractEvacuAgentPedestrianFactory.
  3. The factories are similar enough that the methods Awake() and CreateEvacuAgentPedestrian can be copied into the new factory script. The items that will need to be changed can be seen below. New factory items to change
  4. Blue shows the maximum number of groups the factory can instantiate. This needs to be changed by adding public static int NUMBER_OF_EXAMPLE_AGENTS with an int value to EvacuAgentSceneParamaters and then changing the new factory script file to the property added in EvacuAgentSceneParamaters.
  5. Red and Yellow is a bool for if the highlights for this Pedestrian type are currentlytoggled on so that new pedestrians spawned will have the highlight enabled on spawn. This needs to be changed by adding public static bool IS_EXAMPLE_HIGHTLIGHT_VISUAL_ENABLED with a false value to EvacuAgentSceneParamaters and then changing the new factory script file to the property added in EvacuAgentSceneParamaters for both references.
  6. Green is the minimum and maximum number of followers or non-leader members a group can have. This needs to be changed by adding public static int EXAMPLE_GROUP_FOLLOWER_COUNT_MINIMUM and public static int EXAMPLE_GROUP_FOLLOWER_COUNT_MAXIMUM with a int values to EvacuAgentSceneParamaters and then changing the new factory script file to the properties added in EvacuAgentSceneParamaters.
  7. A fully worked example can be seen below:
public class ExampleLeaderFollowerPedestrianFactory : AbstractEvacuAgentPedestrianFactory
    private void Awake()
        numPedestriansToSpawn = EvacuAgentSceneParamaters.NUMBER_OF_EXAMPLE_AGENTS;
        numberOfFollowersLeftToSpawn = 0;

    public override EvacuAgentPedestrianBase CreateEvacuAgentPedestrian(Pedestrian pedestrian)
        if (numberOfFollowersLeftToSpawn == 0)
            EvacuAgentPedestrianBase groupLeaderPedestrian = CreatePedestrianType(pedestrian, EvacuAgentSceneParamaters.IS_EXAMPLE_HIGHTLIGHT_VISUAL_ENABLED, leaderPedestrianTypePrefab);
            currentLeaderPedestrian = groupLeaderPedestrian;
            numberOfFollowersLeftToSpawn = GetNumberOfFollowersForCurrentGroup(EvacuAgentSceneParamaters.EXAMPLE_GROUP_FOLLOWER_COUNT_MINIMUM, EvacuAgentSceneParamaters.EXAMPLE_GROUP_FOLLOWER_COUNT_MAXIMUM);
            return UpdateGroupCollection();

        EvacuAgentPedestrianBase groupFollowerPedestrian = CreatePedestrianType(pedestrian, EvacuAgentSceneParamaters.IS_EXAMPLE_HIGHTLIGHT_VISUAL_ENABLED, followerPedestrianTypePrefab);
        return AssignToFollowerCollection(groupFollowerPedestrian);

7. Add the new factory to PedestrianFactory

  1. Any scene that spawns Pedestrian needs to have a single GameObject with a PedestrianFactory attached to it as well as specific EvacuAgent factories such as WorkerLeaderFollowerPedestrianFactory.
  2. To enable new Pedestrian to be spawned use the Add Component button on the PedestrianFactory GameObject to add the factory made in Steps 5.1 to 5.6 dragging and dropping the appropriate prefabs as seen below. Note that pedestrians that are only have leaders are allowed but both boxes must be set as the leader pedestrian. Add new pedestrian factory to scene
  3. In PedestrianFactory.SetUpEvacuAgentPedestrianFactories add gameObject.GetComponent<ExampleLeaderFollowerPedestrianFactory>(). Note that commenting these factories out allows you to spawn only specific Pedestrian types for easier debugging.
private List<AbstractEvacuAgentPedestrianFactory> SetUpEvacuAgentPedestrianFactories()
      return new List<AbstractEvacuAgentPedestrianFactory>()