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Add TrafficLights

To add TrafficLights into your Environment follow steps below.


In the Environment you are creating there will most likely be many TrafficLights that should look and work the same way. To simplify the process of creating an environment it is advised to create one TrafficLight of each type with this tutorial and then save them as prefabs that you will be able to reuse.

1. Add TrafficLight Object

Into your Map object in the Hierarchy view add a new Child Object and name it appropriately.

add traffic light object

2. Add a Mesh Filter and select meshes

  1. Click on the Add Component button.

    add traffic light component

  2. Search for Mesh filter and select it by clicking on it.

    search mesh filter

  3. For each TrafficLight specify the mesh you want to use.

    traffic light mesh

3.Add a Mesh Renderer and specify materials

  1. The same way as above search for Mesh Renderer and select it.

    search mesh renderer

  2. Now you need to specify individual component materials.

    For example in the Traffic.Lights.001 mesh there are four sub-meshes that need their individual materials.

    To specify a material click on the selection button on Materials element and search for the material you want to use and select it.

    specify material

    Repeat this process until you specify all materials. When you add one material more than there are sub-meshes you will see this warning. Then just remove the last material and the TrafficLight is prepared.

    too many traffic materials


    Different material for every bulb is necessary for the color changing behavior that we expect from traffic lights. Even though in most cases you will use the same material for every Bulb, having them as different elements is necessary. Please only use models of TrafficLights that have different Materials Elements for every Bulb.

    Materials order

    When specifying materials remember the order in which they are used in the mesh. Especially remember what Materials Elements are associated with every Bulb in the TrafficLight. This information will be needed later.


    In the case of Traffic.Lights.001 the bulb materials are ordered starting from the left side with index 1 and increasing to the right.

    bulb 1

    bulb 2

    bulb 3

4. Add a Mesh Collider

The same way as above search for Mesh Collider and select it. Collider may not seem useful, as the TrafficLight in many cases will be out of reach of vehicles. It is however used for LiDAR simulation, so it is advised to always add colliders to Objects that should be detected by LiDARs.

search mesh collider

5. Position TrafficLight in the Environment

Finally after configuring all visual aspects of the TrafficLight you can position it in the environment. Do this by dragging a TrafficLight with a square representing a plane or with an arrow representing one axis.


6. Add TrafficLight Script

The Traffic Light Script will enable you to control how the TrafficLight lights up and create sequences.

  1. Click on Add Component, search for the Traffic Light script and select it.

    traffic light script

  2. You should see the Bulb Emission config already configured. These are the colors that will be used to light up the Bulbs in TrafficLight. You may adjust them to suit your needs.

    bulb emission config

  3. You will have to specify Bulb material config, in which you should add elements with fields:

    • Bulb Type - One of the predefined Bulb types that describes the Bulb (its color and pattern).

    • Material Index - Index of the material that you want to be associated with the Bulb Type. This is where you need to use the knowledge from earlier where we said you have to remember what Materials Element corresponds to which bulb sub-mesh.

    Bulb configuration example

    Here we specify an element Type as RED_BULB and associate it with Material that has an index 3. This will result in associating the right most bulb with the name RED_BULB. This information will be of use to us when specifying TrafficLights sequences.

    traffic light bulb config


Once you have added TrafficLights to your Environment, you can start configuring RandomTraffic which will add moving vehicles to it! Details here.