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Segmentation Overview

RoadRunner has the ability to export scene geometry by category for easy generation of segmentation training data.

Segmentation categories are identified in the export scene by using suffixes applied to each material name. For example, a material named "Concrete" that is applied to a curb is named "Concrete_Curb" on export. The exported material inherits the built-in segmentation category suffix "Curb", which uniquely distinguishes it from the material "Concrete_Sidewalk" applied to neighboring sidewalk geometry.

Toggle Segmentation Display

  1. To enter segmentation display, select View > Sensor > Segmented.

  2. To exit segmentation display, select View > Sensor > Camera.


RoadRunner uses a default set of segmentation categories when building geometry within a scene. These categories include: Road, Sidewalk, Curb, Gutter, Marking, Ground, Building, Vehicle, Bike, Pedestrian, Sign, Signal, Foliage, and Prop.

Additionally, you can extend these categories and assign them to the following project asset types: Props, Signals, Lane Markings, Polygon Markings, Stencils.

Add a Custom Category

  1. In a text editor, open the SegmentationCategories.xml file located in the project's "Project" folder. If the file does not exist, create one.

  2. Add a new Category entry. Include a name and color attribute, which are used during export and segmentation display, respectively.

  3. Existing categories can also be modified or removed. Changing the name of an existing category is equivalent to removing the old category and adding a new one. Existing assets referencing this old name will default.

  4. Save the file and restart RoadRunner. New categories are available only after the project is reloaded.

This code shows an example SegmentationCategories.xml file.

<?xml version="1.0"?>
	<Category name="Bush" color="#7BA269"/>
	<Category name="Tree" color="#0F5F32"/>
	<Category name="Crosswalk" color="#963"/>
	<Category name="DashedMarking" color="#369"/>
	<Category name="SolidMarking" color="#48a"/>
	<Category name="DoubleMarking" color="#69b"/>

Export Scene Geometry Grouped for Segmentation

On export, RoadRunner supports grouping materials by segmentation category or separating them into individual meshes. To toggle between these options, follow these steps.

  1. Select File > Export and select a triangulated format, such as Filmbox or OpenFlight.

  2. In the export dialog box, fill out the file location and any tiling options.

  3. Optionally use the Split by Segmentation toggle in the Options group to control whether each mesh is split by category or remains grouped.

  4. Click Export.

Assign a Category to an Asset

  1. Select the asset in the Library Browser.

  2. In the Attributes Panel, under Segmentation, select the appropriate category.

  3. Select File > Save Project in the Menu Bar.