ReferenceLane

Reference lane of road in RoadRunner scene

Since R2025a

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    Description

    The ReferenceLane object defines the center lane, or reference line, of a road in a RoadRunner scene. This lane has no width and serves as the basis for positioning all other lanes, which are arranged outward from the reference line. You can use the ReferenceLane object to programmatically add lanes on either side of the reference line using addLaneToRight and addLaneToLeft functions, respectively. Each road must have at least a reference lane and one additional lane with a specified width. The reference lane is composed of a sequence of parametric spans, represented as an ordered collection of nodes connected by spans between each pair of adjacent nodes. You can use the LaneMarkingProfile property to assign lane markings to each span of the reference lane.

    Creation

    To retrieve a ReferenceLane object that represents the reference line of a road from your RoadRunner scene, extract the ReferenceLane property of the road. For example, refLane = rrRoad.ReferenceLane extracts the ReferenceLane object from the ReferenceLane property of the road rrRoad and assigns it to the variable refLane.

    Properties

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    This property is read-only.

    Lane marking profile for the reference lane, represented as a LaneMarkingProfile object. The marking profile of a lane defines the markings on the outer boundary of the lane.

    Object Functions

    addLaneToRightAdd lane to right side of specific lane, relative to road direction
    addLaneToLeftAdd lane to left side of specific lane, relative to road direction

    Examples

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    This example uses:

    Open Live Script

    This example shows how to create a RoadRunner scene with single horizontal road and add two driving lanes with opposite travel directions.

    Create a roadrunner object, specifying the path to an existing project. For example, this code shows the path to a project, on a Windows® machine, located at "C:\RR\MyProject". This code assumes that RoadRunner is installed in the default location, and returns an object, rrApp, that provides functions for performing basic tasks such as opening, closing, and saving scenes and projects.

    rrApp = roadrunner(ProjectFolder="C:\RR\MyProject");

    Note: If you are opening RoadRunner from MATLAB for the first time, or if you have changed the RoadRunner installation location since you last opened it from MATLAB, you can use the roadrunnerSetup function to specify new default project and installation folders to use when opening RoadRunner. You can save these folders between MATLAB sessions by selecting the Across MATLAB sessions option from the corresponding drop down.

    Create a new RoadRunner scene in the current project by using the newScene function, specifying the roadrunner object rrApp.

    newScene(rrApp);

    Create an object for the RoadRunner authoring API, rrApi, that references the object for the current RoadRunner instance rrApp. The rrApi object enables you to programmatically author scenes, such as by adding and modifying road and lanes components, using MATLAB.

    rrApi = roadrunnerAPI(rrApp);

    Extract the object for your scene from the Scene property of the authoring API object rrApi. The extracted Scene object enables you to specify the scene in which to add scene elements such as roads and lanes.

    scn = rrApi.Scene;

    Add 100 meters long horizontal line-arc curve road to the scene by using the addLineArcRoad function. Specify the position of the road by specifying the positions of its control points along the X- and Y- axes of the RoadRunner local coordinate system. These control points define the position of the start and end of the road. You can modify the position of the control points to adjust the length and direction of the road relative to the scene origin. You can also add additional control points in between the start and end points of the line-arc curve to adjust curvature and radius of the road curve.

    controlPoints = [-50 0; 50 0];
rrHorizontalRoad = addLineArcRoad(scn,controlPoints);

    Extract the reference lane of the road from the ReferenceLane property of the road object rrHorizontalRoad. The reference lane defines the center lane, or reference line, of a road in a RoadRunner scene. This lane has no width and serves as the basis for positioning all other lanes, which are arranged outward from the reference line.

    refLane = rrHorizontalRoad.ReferenceLane;

    Roadrunner scene canvas with a reference lane

    Use the extracted refLane object to add lanes on either side of the reference lane of the road using the addLaneToLeft and addLaneToRight functions. Then, use the LaneType and TravelDirection properties of the added lanes to specify the type of lane and the travel direction of each lane. Add a driving lane to the left of the horizontal road with forward travel direction.

    horizontalLane1 = addLaneToLeft(refLane);
horizontalLane1.LaneType = "Driving";
horizontalLane1.TravelDirection = "Forward";

    Roadrunner scene canvas with a driving lane to the left of the reference lane

    Add another driving lane to the right of the horizontal road with backward travel direction.

    horizontalLane2 = addLaneToRight(refLane);
horizontalLane2.LaneType = "Driving";
horizontalLane2.TravelDirection = "Backward";

    This figure shows the scene in the RoadRunner scene canvas.

    Roadrunner scene canvas with two driving lanes with one forward and one backward travel direction

    Version History

    Introduced in R2025a

    See Also

    | | | (RoadRunner) |