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Create Simple RoadRunner Scene

RoadRunner is an interactive editor that lets you design 3D scenes for simulating and testing automated driving systems. This example shows how to create a simple scene containing an intersection, bridges, and trees in the surrounding terrain, similar to the scene shown here:

A simple RoadRunner scene


Before beginning this example, make sure that your system meets these prerequisites:

Although this example covers some basic camera operations, for a more complete understanding of how the RoadRunner camera works, consider reviewing the Camera Control in RoadRunner example first.

Create New Scene and Project

In RoadRunner, each scene you create is part of a project, which is a folder of assets (scene components) that can be shared across all scenes in that project. Create a new scene and a new project in which to put that scene.

  1. Open RoadRunner, and from the start page, click New Scene.

  2. On the Select a Project window, click New Project.

  3. In your file system, browse for an empty folder in which to create the project. If an empty folder does not exist, create one and name it My Project. The folder name becomes the name of the project.

  4. When prompted, click Yes to install the RoadRunner Asset Library in your project.

RoadRunner opens to a new scene with an empty scene editing canvas.

Empty RoadRunner scene editing canvas

The name of the project that you specified appears in the title bar. The name of the scene also appears in the title bar, but it is displayed as New Scene until you save the scene and give it a name.

RoadRunner title bar

You can create a new scene, change scenes, or change projects at any time from the File menu. When you reopen RoadRunner, you can select recent scenes that you worked on from the start page, in the Recent Scenes list.

Add Roads

When you open a new scene, RoadRunner opens with the Road Plan Tool selected. Instructions on using this tool appear in the bottom status bar. By right-clicking in the scene editing canvas with this tool selected, you can add control points that shape the geometry of a road.

  1. At the bottom center of the scene editing canvas, right-click to add the first control point of a new road.

    Red control point at bottom-center of canvas

  2. At the top center of the canvas, right-click to add a second control point and form your first road segment.

    Road segment running from bottom to top of canvas

  3. Click away from the road to deselect the road and finish creating it.

    Finished road, no longer selected

  4. Create a new straight road that intersects the first road by right-clicking to its left, right-clicking to its right, and then clicking away from the road. The two roads form a junction.

    Straight intersecting roads that form a junction

So far you have created straight roads. To form curved roads, right-click multiple times to add additional control points to a road. Create a curved road that overlaps the intersection.

  1. Right-click within the top-left quadrant of the intersection.

  2. Right-click within the top-right quadrant of the intersection. The first created road segment is straight.

  3. Right-click in the bottom-right quadrant of the intersection. The area enclosed within the intersection and the curved road forms a ground surface.

    Curved road added to intersection in three steps

You can extend existing roads by selecting the endpoint of a road and right-clicking to add more control points.

  1. In the curved road you created, click to select the end near the top of the canvas.

  2. Right-click the left end of the intersection. RoadRunner creates a road that meets the necessary geometric constraints. The enclosed area again forms a ground surface.

    Road connecting the left side of the curved road to the left side of the intersection

To modify any road, click to select it and try dragging its control points or moving the entire road. You can also right-click a road to add additional control points. For example, in this road network, you can add control points to smooth out the curve on the left side of the intersection.

Add Surface Terrain

So far, only the areas enclosed by roads contain surface terrain. To add surface terrain around the entire road network, you can use the Surface Tool .

  1. In the toolbar, click the Surface Tool button. Selecting a new tool puts RoadRunner in a different mode that enables new interactions and makes different scene objects selectable. With the Surface Tool selected, the roads are no longer selectable but the road surface nodes become selectable.

    Road networks with surface nodes selectable

  2. Zoom out of the scene, either by using the scroll wheel or by holding Alt and right-click and then dragging down or left.

    Road network zoomed out

  3. Right-click above the road network to add a new surface node. Then, keep right-clicking at points around the road to form a circle. When you reach the top node again, right-click it to connect the surface graph and commit the surface to the canvas.

    Surface being added around road network in 6 steps

To modify the surface size, click and drag the surface nodes. To modify the curve of the surface, click the segments between nodes, and then click and drag the tangent lines.

Add Elevation and Bridges

Up to this point, the scene has been flat. Modify elevation in the scene by changing the height of one of the roads.

  1. Hold Alt and then click and drag the camera to view the scene at an angle.

    Scene viewed at an angle

  2. Click the Road Plan Tool button to make roads selectable again. Then, click to select the first curved road that you created.

    Curved road selected

  3. To elevate the road, use the 2D Editor, which enables you to view scene aspects such as road profiles and road cross-sections. In the 2D Editor, select the road profile and raise it approximately 10 meters.

    On left, 2D Editor with road flat. On right, 2D Editor with road raised 10 meters.

    The road is now elevated in the scene canvas above the intersection. Instead of forming junctions, the elevated road forms overpasses.

    Curved road elevated above the intersection

Roads attach to the surface terrain. When you elevate a road, the terrain elevates with it. Increasing elevation can lead to visual artifacts below the overpasses. To resolve this issue, you can create bridge spans by using the Road Construction Tool .

  1. Rotate the camera and zoom in to see the visual artifacts at the overpasses.

    Road with visual artifacts present

  2. Click the Road Construction Tool button.

  3. On the left toolbar, click the Auto Assign Bridges button . This operation, which is available only when you are using the Road Construction Tool, converts only those road sections that are directly above a region to bridge spans. Use the default bridge span inflation and click OK. The roads spans are converted to bridges and the visual artifacts are removed.

    Road with bridge spans and no visual artifacts

    If the bridges do not form correctly, try adjusting the road elevation or the bridge span inflation and rerun the Auto Assign Bridges operation.

Modify Junction

Some tools enable you to select and modify properties at junctions. Modify the corner radius of the four-way intersection.

  1. Click the Corner Tool button , and then click to select the four-way intersection.

    Intersection with four-way intersection selected

  2. By default the junction has a corner radius of 5 meters. Increase this value by using the Attributes pane. This pane contains information and editable attributes about currently selected items. In the Corner Tool, selecting the junction selects all four corners of the junction, so you can modify the attributes of all four corners at the same time.

    In the Attributes pane, set the Corner Radius attribute of all four corners to 10.

    Attributes pane of junction with Corner Radius set to 10

    The junction corners expand in the scene editing canvas.

    Intersection with junction corners expanded

Alternatively, you can modify the Corner Radius attribute value by clicking on the attribute name Corner Radius attribute name selected and dragging up or down.

Add Crosswalk

Add a crosswalk to the intersection.

  1. Rotate the camera to view the intersection from the top down. To focus the camera on the selected intersection, press the F key.

    Top-down view of intersection

  2. Click the Crosswalk and Stop Line Tool button . The intersection displays blue chevrons for adding stop lines to the intersection.

    Intersection with blue chevrons that preview where stop lines are added

  3. From the Library Browser, select a crosswalk to add to the intersection. The Library Browser stores all assets available to add to a scene. Assets include 3D objects, markings, textures, and materials.

    In the Library Browser, select the Markings folder, and then select the ContinentalCrosswalk asset. A preview of the asset displays in the asset viewer.

    Library Browser with continental crosswalk asset selected

  4. Click within the intersection to clear the blue chevrons. Then, right-click in the intersection to apply the selected crosswalk asset to the intersection.

    Intersection with crosswalk

Add Turning Lanes

Convert one of the roads at the intersection into a more complex highway road that includes a turning lane with arrow markings.

Change Road Style

The existing roads all use the default road style, which is of a simple two-lane divided highway with sidewalks. Update one of the roads at the intersection to use a road style with additional lanes.

  1. Zoom out and rotate the camera to view the scene at an angle similar to the one shown here.

    Scene viewed at an angle, with one of the intersecting roads facing the camera

  2. In the Library Browser, open the RoadStyles folder, and then select the MainStreetCenterTurn asset. This road style asset includes shoulder lanes, two passing lanes on each side, and a median lane. Optionally, rotate and move the camera in the asset viewer to inspect the road style.

    Library Browser with road style asset selected

  3. Drag the selected road style onto the road closest to the camera, as shown here. The road updates to the new style and switches back to the Road Plan Tool. The road maintains the corner radius and crosswalk style previously applied.

    Road with new road style applied

Create Turning Lane at Intersection

Create a short left-hand turn lane near the intersection.

  1. Rotate the camera and zoom in near the crosswalk on one side of the road that has the new road style.

    One side of intersection with the crosswalk at the top and the median lane at the center

  2. Click the Lane Carve Tool button . This tool enables you to create a tapering cut in an existing lane to form a turning lane.

  3. Click to select the road. Then, right-click the right side of the median lane where you want the tapering cut to start. Drag the blue line diagonally to the left side of the median lane where you want the tapering cut to end and the turning lane to start.

    Marking carve operation applied to median lane

  4. The newly formed turning lane still has the styles of the median lane. Update the lane markings to match the style of a standard turning lane.

    1. In the Library Browser, select the SolidSingleWhite asset and drag it onto the right side of the turning lane. The lane marking changes to a solid single white line.

      Asset dragged onto right side of turning lane to change it into a solid single white line

    2. Select the SolidDoubleYellow asset and drag it onto the two marking segments that form the left side of the turning lane. The lane marking segments change to solid double yellow lines.

      Assets dragged onto left side of turning lane to change them into solid double yellow lines

  5. Add a turning arrow to the lane. In the Stencils folder of the Library Browser, select the Stencil_ArrowType4L asset. Drag this asset into the turning lane at the point where you want to add the arrow stencil.

    Left arrow stencil dragged to bottom of turning lane

  6. By adding the arrow stencil, RoadRunner selects the Marking Point Tool to make it the active tool. You can now add the second arrow by right-clicking at the point where you want to add it.

    Left arrow stencil copied above the previous stencil

  7. Modify the marking material of the arrows to make them appear more worn. First, select the two arrows. In the Markings folder of the Library Browser, select the LaneMarking2 material asset. Then, drag this asset into the Attributes pane for the selected arrows and over the existing LaneMarking1 material asset.

    Lane marking texture dragged from Library Browser to the Attributes pane for the selected arrows

    The arrows update to use the new more worn-looking material.

    Turning arrows with new material applied

Repeat these steps to create the turning lane on the other side of the intersection.

Intersection with turning lanes on both sides

Add Props

To enhance the scene with more detail, add props to it. Props are 3D objects such as posts, poles, and signs that you can place on and around roads. Add tree props around the road using multiple techniques.

Add Individual Props

Add bushes to one section of the terrain.

  1. Zoom out and rotate the camera to fit the entire road network and surrounding terrain in view.

    Scene with full road network and surrounding terrain in view

  2. In the Library Browser, open the Props folder and select the Trees subfolder.

  3. Select a bush prop (one of the asset files that begins with Bush_). Drag the bush onto a section of the scene. RoadRunner switches to the Prop Point Tool . Drag additional bushes into the scene or right-click to add more bushes. All the bushes are aligned with the surface terrain.

    Three bushes added to scene

Add Props Along Curve

Add props along a curve to follow the edge of the road.

  1. Click the Prop Curve Tool button .

  2. In the Library Browser, in the Trees folder, select a California palm tree prop (one of the asset files that begins with CalPalm_).

  3. Right-click along the road edge of one side of the intersection to add a line of palm trees to it. Click away from the prop curve to complete the line.

    A line of palm trees along one edge of the road

  4. To make each individual tree in the span moveable and selectable, you can convert the curve to individual props. Select the prop curve, and in the Attributes pane, click Bake. The palm trees become individual props and RoadRunner switches to the Prop Point Tool. Move some of the palm trees to the other side of the intersection.

    Palm trees converted to individual props and distributed along both sides of the intersection

Alternatively, to add a prop along a span of road, you can click the Prop Span Tool button , select a road, and drag the prop onto the road edge.

Add Props in Specified Area

Add props in a specified area of the ground surface.

  1. Click the Prop Polygon Tool button .

  2. In the Library Browser, in the Trees folder, select a cypress tree prop (one of the asset files that begins with Cypress_).

  3. Right-click within an empty area of the surface terrain to draw a polygon containing the selected prop. Click away from the polygon to finish drawing it. Then move the points or tangents to change the shape of the polygon.

    Cypress tree props added to a polygon. A tangent to the polygon is selected, which modifies the shape of the polygon.

  4. Optionally, modify the prop polygon by using the attributes in the Attributes pane. For example, to increase or decrease the number of props in the polygon, use the Density attribute. To randomize the distribution of assets in the polygon, click Randomize.

Add Props of Varying Types

So far you have added a single type of prop to the scene. To add a variety of props to a scene simultaneously, you can create a prop set.

  1. In the Library Browser, in the Trees folder, hold Ctrl and select the three props you added to the scene in the previous sections.

  2. Select New, then Prop Set and give the prop set a name. The new prop set is stored in the Trees folder. The Attributes pane displays the three props in the set and a preview of the prop set.

    Attributes pane displaying a prop set containing a bush, palm tree, and cypress tree

  3. Click the Prop Polygon Tool button. Create a prop polygon on an empty part of the terrain that contains the new prop set.

    Prop set added to terrain

    Optionally, you can also replace the existing cypress tree props with the new prop set by dragging the prop set onto the polygon of cypress trees.

Other Things to Try

You have now created a simple road network containing a realistic turning lane, multiple overpasses, and trees of varying types.

Final RoadRunner scene

You can now enhance the scene using additional tools. For example, try these things:

  • Add more roads or connect the existing roads in the scene. To smooth the transitions between roads that have different numbers of lanes, use lane tools such as the Lane Tool, Lane Width Tool, Lane Add Tool, or Lane Form Tool.

  • Add traffic signals to the intersection by using the Signal Tool. To modify the paths through the lanes at each turn signal, use the Maneuver Tool.

  • Add additional props to the scene, such as barrels, buildings, and traffic signs. To modify the text of signs, use the Sign Tool.

In addition, you can try exporting the scene to one of the supported export formats. These export options are on the File menu, under Export. To customize export options before exporting, use the Scene Export Preview Tool. If you are exporting to OpenDRIVE®, use the OpenDRIVE Export Preview Tool. This image shows how the export preview of the scene you created looks when you click the OpenDRIVE Export Preview Tool button .

Preview of RoadRunner scene when exporting to OpenDRIVE

If you want to create a new scene that is based on a real-world location, then you can import geographic information system (GIS) data such as aerial imagery into RoadRunner and create scenes around it. For an example, see Create Roads Around Imported GIS Assets.

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