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PhysX SDK lightbeam sensor#

Deprecated since version 6.0: The PhysX SDK sensor extensions (isaacsim.sensors.physx) are deprecated. Use isaacsim.sensors.experimental.physics.RaycastSensor as the replacement for raycast-based sensing. For lightbeam/safety-curtain specific functionality, consider using the RaycastSensor with appropriate configuration. See Migrating to the physics raycast sensor for step-by-step migration instructions, or the isaacsim.sensors.experimental.physics API Documentation for the replacement APIs.

The PhysX SDK lightbeam sensor in Isaac Sim uses PhysX SDK raycasts to determine if an object has intersected a light beam. You can specify the number of rays and height to create a safety light “curtain” of lightbeam sensors.

See the Isaac Sim Conventions documentation for a complete list of Isaac Sim conventions.

Examples#

  • PhysX SDK Lightbeam Sensor example: Robotics Examples > Sensors > Lightbeam

To run the example:

  1. Activate Robotics Examples tab from Windows > Examples > Robotics Examples.

  2. Click Robotics Examples > Sensors > Lightbeam.

  3. Verify that you have a window containing empty data for each lightbeam, which populates with data after you press Play. It shows if each beam was hit, the linear depth of the hit, and the exact hit position in xyz.

  4. Press the Play button to begin simulating.

  5. Press SHIFT + LEFT_CLICK to drag the cube or sensor around and see changes in the readings.

Lightbeam sensor example viewport.

Migrating to the physics raycast sensor#

The PhysX SDK lightbeam sensor is deprecated. Use the Physics Raycast Sensor (isaacsim.sensors.experimental.physics.RaycastSensor) configured as a beam curtain to achieve the same functionality.

Concept mapping#

PhysX SDK Lightbeam Sensor

Physics Raycast Sensor

numRays

Length of the rayOrigins / rayDirections arrays. Create one entry per beam.

curtainLength / curtainAxis

rayOrigins. Spread ray origins along the curtain axis. For example, for a vertical curtain of height h with N beams: origins[i] = [0, 0, -h/2 + h * i / (N-1)].

forwardAxis

rayDirections. Set all direction vectors to the forward axis. For example, [1, 0, 0] for a curtain firing along the X axis.

minRange / maxRange

minRange / maxRange. Same semantics.

Per-beam hit / depth / position data

RaycastSensor.get_sensor_reading() returns per-ray depths, hit positions, and hit normals.

Interactive example#

The Physics Raycast Sensor example includes a beam curtain sensor configuration with parallel vertical rays:

  • GUI: Open Robotics Examples > Sensors > Physics Raycast Sensor and click Load Scene.

  • Source code: source/extensions/isaacsim.sensors.physics.examples/isaacsim/sensors/physics/examples/raycast_sensor.py

See Physics raycast sensor for the full documentation, including Python API usage and OmniGraph workflows.