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Simulation 3D Ray Tracer

Implement ray tracing in 3D environment

  • Library:
  • Vehicle Dynamics Blockset / Vehicle Scenarios / Sim3D / Sim3D Vehicle / Components

  • Simulation 3D Ray Tracer block

Description

The Simulation 3D Ray Tracer block implements ray tracing to get the positions, surface normals, surface identifiers, and distances for objects in the scene. You can specify block parameters that configure the ray origins, directions, and lengths to adjust the ray trace sensor pattern for your scene and test scenario.

Tip

Verify that the Simulation 3D Scene Configuration block executes before the Simulation 3D Ray Tracer block. That way, the Unreal Engine® 3D visualization environment prepares the data before the Simulation 3D Ray Tracer block receives it. To check the block execution order, right-click the blocks and select Properties. On the General tab, confirm these Priority settings:

  • Simulation 3D Scene Configuration0

  • Simulation 3D Terrain Sensor1

For more information about execution order, see Control and Display Execution Order.

Ports

Output

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Hit locations, returned as a real-valued N(B+1)-by-3 array of the form [X, Y, Z], in meters. N is the number of rays and B is the number of bounces per ray.

If you mount the sensor to a vehicle by setting Parent name to the name of that vehicle, then X, Y, and Z are in the 3D visualization engine coordinate system, where:

  • The X-axis points forward from the vehicle

  • The Y-axis points to the right of the vehicle, as viewed when looking in the forward direction of the vehicle

  • The Z-axis points up

Data Types: double

Ray normal to the hit location, returned as a real-valued N(B+1)-by-3 array of the form [X, Y, Z], in meters. N is the number of rays and B is the number of bounces per ray.

If you mount the sensor to a vehicle by setting Parent name to the name of that vehicle, then X, Y, and Z are in the 3D visualization engine coordinate system, where:

  • The X-axis points forward from the vehicle

  • The Y-axis points to the right of the vehicle, as viewed when looking in the forward direction of the vehicle

  • The Z-axis points up

Data Types: double

Ray distance to hit location, returned as a real-valued N(B+1)-by-1 vector N, in meters. N is the number of rays and B is the number of bounces per ray.

Data Types: double

Object identifier of the surfaces hit by the ray, returned as an integer-valued N(B+1)-by-1 vector N. N is the number of rays and B is the number of bounces per ray.

The returned surface identifiers are the object values specified when creating custom surfaces in the Unreal® Editor. If a surface identifier is unknown, the block assigns it an ID of 0. For information about adding surfaces, see Add a Surface Type in the Unreal Engine documentation.

Data Types: uint8

Hit flag, returned as a N-by-1 Boolean vector. N is the number of rays. A value of 1 indicates the ray hit a surface.

Data Types: Boolean

Parameters

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Mounting

Unique sensor identifier, specified as a positive integer. In a multisensor system, the sensor identifier distinguishes between sensors. When you add a new sensor block to your model, the Sensor identifier of that block is N + 1. N is the highest Sensor identifier value among existing sensor blocks in the model.

Example: 2

Name of parent to which the sensor is mounted, specified as the name of a vehicle in your model, or Scene Origin. The vehicle names that you can select correspond to the Name parameters of the simulation 3D vehicle blocks in your model.

Sensor mounting location.

  • When Parent name is Scene Origin, the block mounts the sensor to the origin of the scene. You can set the Mounting location to Origin only. During simulation, the sensor remains stationary.

  • When Parent name is the name of a vehicle, the block mounts the sensor to one of the predefined mounting locations described in the table. During simulation, the sensor travels with the vehicle.

Vehicle Mounting LocationDescriptionOrientation Relative to Vehicle Origin [Roll, Pitch, Yaw] (deg)
Origin

Forward-facing sensor mounted to the vehicle origin, which is on the ground and at the geometric center of the vehicle (see Coordinate Systems in Vehicle Dynamics Blockset)

Vehicle with sensor mounted at origin

[0, 0, 0]
Front bumper

Forward-facing sensor mounted to the front bumper

Vehicle with sensor mounted at front bumper

[0, 0, 0]
Rear bumper

Backward-facing sensor mounted to the rear bumper

Vehicle with sensor mounted at rear bumper

[0, 0, 180]
Right mirror

Downward-facing sensor mounted to the right side-view mirror

Vehicle with sensor mounted at right side-view mirror

[0, –90, 0]
Left mirror

Downward-facing sensor mounted to the left side-view mirror

Vehicle with sensor mounted at left side-view mirror

[0, –90, 0]
Rearview mirror

Forward-facing sensor mounted to the rearview mirror, inside the vehicle

Vehicle with sensor mounted at rearview mirror

[0, 0, 0]
Hood center

Forward-facing sensor mounted to the center of the hood

Vehicle with sensor mounted at hood center

[0, 0, 0]
Roof center

Forward-facing sensor mounted to the center of the roof

Vehicle with sensor mounted at roof center

[0, 0, 0]

Roll, pitch, and yaw are clockwise-positive when looking in the positive direction of the X-axis, Y-axis, and Z-axis, respectively. When looking at a vehicle from the top down, the yaw angle (that is, the orientation angle) is counterclockwise-positive because you are looking in the negative direction of the axis.

The X-Y-Z mounting location of the sensor relative to the vehicle depends on the vehicle type. To specify the vehicle type, use the Type parameter of the Simulation 3D Vehicle block to which you mount the sensor. To obtain the X-Y-Z mounting locations for a vehicle type, see the reference page for that vehicle.

To determine the location of the sensor in world coordinates, open the sensor block. Then, on the Ground Truth tab, select the Output location (m) and orientation (rad) parameter and inspect the data from the Location output port.

Select this parameter to specify an offset from the mounting location by using the Relative translation [X, Y, Z] (m) and Relative rotation [Roll, Pitch, Yaw] (deg) parameters.

Translation offset relative to the mounting location of the sensor, specified as a real-valued 1-by-3 vector of the form [X, Y, Z], in meters.

If you mount the sensor to a vehicle by setting Parent name to the name of that vehicle, then X, Y, and Z are in the vehicle coordinate system, where:

  • The X-axis points forward from the vehicle

  • The Y-axis points to the left of the vehicle, as viewed when looking in the forward direction of the vehicle

  • The Z-axis points up

The origin is the mounting location specified in the Mounting location parameter. This origin is different from the vehicle origin, which is the geometric center of the vehicle.

If you mount the sensor to the scene origin by setting Parent name to Scene Origin, then X, Y, and Z are in the world coordinates of the scene.

For more details about the vehicle and world coordinate systems, see Coordinate Systems in Vehicle Dynamics Blockset.

Example: [0,0,0.01]

Dependencies

To enable this parameter, select Specify offset.

Rotational offset relative to the mounting location of the sensor, specified as a real-valued 1-by-3 vector of the form [Roll, Pitch, Yaw], in degrees. Roll, pitch, and yaw are the angles of rotation about the X-, Y-, and Z-axes, respectively.

If you mount the sensor to a vehicle by setting Parent name to the name of that vehicle, then X, Y, and Z are in the vehicle coordinate system, where:

  • The X-axis points forward from the vehicle.

  • The Y-axis points to the left of the vehicle, as viewed when looking in the forward direction of the vehicle.

  • The Z-axis points up.

  • Roll, pitch, and yaw are clockwise-positive when looking in the forward direction of the X-axis, Y-axis, and Z-axis, respectively. If you view a scene from a 2D top-down perspective, then the yaw angle (also called the orientation angle) is counterclockwise-positive because you are viewing the scene in the negative direction of the Z-axis.

The origin is the mounting location specified in the Mounting location parameter. This origin is different from the vehicle origin, which is the geometric center of the vehicle.

If you mount the sensor to the scene origin by setting Parent name to Scene Origin, then X, Y, and Z are in the world coordinates of the scene.

For more details about the vehicle and world coordinate systems, see Coordinate Systems in Vehicle Dynamics Blockset.

Example: [0,0,10]

Dependencies

To enable this parameter, select Specify offset.

Parameters

Ray origin relative to sensor mounting location, specified as a real-valued N-by-3 array of the form [X, Y, Z], in meters. N is the number of rays.

If you mount the sensor to a vehicle by setting Parent name to the name of that vehicle, then X, Y, and Z are in the 3D visualization engine coordinate system, where:

  • The X-axis points forward from the vehicle

  • The Y-axis points to the right of the vehicle, as viewed when looking in the forward direction of the vehicle

  • The Z-axis points up

Example: zeros(10,3)

Normalized ray direction relative to sensor mounting location, specified as a real-valued N-by-3 array of the form [X, Y, Z]. N is the number of rays. The units are dimensionless.

If you mount the sensor to a vehicle by setting Parent name to the name of that vehicle, then X, Y, and Z are in the 3D visualization engine coordinate system, where:

  • The X-axis points forward from the vehicle

  • The Y-axis points to the right of the vehicle, as viewed when looking in the forward direction of the vehicle

  • The Z-axis points up

Example: ones(10,3)

Maximum total ray length of a multi-bounce trace path, specified as a real-valued N-by-1 vector, in meters. N is the number of rays.

Example: ones(10,1)*10

Number of bounces that a trace may have before terminating, B, specified as an integer.

Example: 0

Whether to enable Unreal Engine trace line visualization for the ray tracer.

Whether to enable optimization of the ray tracer. Enabling this parameter allows the block to perform concurrent traces. Enable this parameter when the number of traces is large and your machine has multiple cores.

Sample time of the block, in seconds, specified as a positive scalar. The 3D simulation environment frame rate is the inverse of the sample time.

If you set the sample time to -1, the block inherits its sample time from the Simulation 3D Scene Configuration block.

Version History

Introduced in R2022b