LiDAR Simulation¶

The simulator represents obstacles as polygons in map coordinates. The current simulation.launch.py reads <map_name>.obstacles.yaml from the selected map package and starts sim_lidar.py when that file contains obstacles.

Obstacle editor¶

Run the Tk editor from the repository root in a graphical environment:

python3 src/svea_core/util/obstacles_builder_gui.py

The editor imports ROS message definitions and needs a sourced ROS environment, Tk, NumPy, Pillow and PyYAML. Install missing GUI dependencies on the machine where you run it. util/run does not automatically configure display forwarding; see visualization options.

Use Load map to select src/svea_core/maps/floor2.yaml (with its referenced PGM image). The editor also accepts legacy pickled OccupancyGrid maps; only load trusted pickle files. It supports zoom/pan, undoing points, clearing polygons and simplifying them. Coordinates exported after zoom/pan remain in the map frame.

Draw polygons, finish each obstacle, then choose an obstacles export format and save as floor2.obstacles.yaml alongside the map. Both the plain form below and the editor's ROS parameter wrapper are accepted by the launch loader:

obstacles:
  - [[0.0, 0.0], [1.0, 0.0], [1.0, 1.0], [0.0, 1.0]]

Do not repeat the first vertex; the simulator closes the polygon. The editor's stay_in/keep_out track formats are separate outputs and are not the obstacle list consumed by this launch file. Keep copies of the supplied maps and obstacles if you need to preserve the original course layout.

Run and inspect¶

After editing installed map data, rebuild the map package and source the workspace. The supplied Floor 2 obstacle file enables scans for both vehicles:

ros2 launch svea_examples floor2.launch.py

In another sourced terminal in the same container/domain:

ros2 topic info /svea_a/scan
ros2 topic hz /svea_a/scan
ros2 topic echo /svea_a/scan --once

scan is a sensor_msgs/msg/LaserScan topic relative to the vehicle namespace. The simulator also publishes viz_lidar_points, viz_lidar_rays, and viz_edges. Enable the relevant topics in Foxglove's 3D panel; they may be hidden in the supplied layout. A controller must explicitly subscribe to scans; LocalizationInterface does not provide a scan callback automatically.

To test another map, provide its YAML/PGM and matching obstacle file through the selected map package and include simulation.launch.py with that map_name. floor2.launch.py itself fixes the map name to floor2.