Simulation 3D Ray Tracer

Implement ray tracing in 3D environment

Since R2024a

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Libraries:
Vehicle Dynamics Blockset / Vehicle Scenarios / Sim3D / Sim3D Vehicle / Components
Simulink 3D Animation / Simulation 3D / Sensors

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 Configuration — 0

• Simulation 3D Terrain Sensor — 1

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

Ports

Output

HitLocations — Hit locations

real-valued N(B+1)-by-3 array

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

HitNormals — Ray normal to hit location

real-valued N(B+1)-by-3 array

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

HitDistances — Ray distance to hit location

real-valued N(B+1)-by-1 array

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

SurfaceIds — Object IDs of hit surfaces

integer-valued N(B+1)-by-1 vector | 0

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

IsValidHit — Hit flag

N-by-1 vector

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

Mounting

Sensor identifier — Unique sensor identifier

1 (default) | positive integer

Specify the unique identifier of the sensor. In a multisensor system, the sensor identifier enables you to distinguish between sensors. When you add a new sensor block to your model, the Sensor identifier of that block is N + 1, where N is the highest Sensor identifier value among the existing sensor blocks in the model.

Example: 2

Parent name — Name of parent

Scene Origin (default)

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.

Mounting location — Sensor mounting location

Origin (default) | Front bumper | Rear bumper | Right mirror | Left mirror | Rearview mirror | Hood center | Roof center | ...

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 Location	Description	Orientation 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 for Unreal Engine Simulation in Automated Driving Toolbox (Automated Driving Toolbox))	[0, 0, 0]
Front bumper Front center	Forward-facing sensor mounted to the front bumper	[0, 0, 0]
Rear bumper Rear center	Backward-facing sensor mounted to the rear bumper	[0, 0, 180]
Right mirror	Downward-facing sensor mounted to the right side-view mirror	[0, –90, 0]
Left mirror	Downward-facing sensor mounted to the left side-view mirror	[0, –90, 0]
Rearview mirror	Forward-facing sensor mounted to the rearview mirror, inside the vehicle	[0, 0, 0]
Hood center	Forward-facing sensor mounted to the center of the hood	[0, 0, 0]
Roof center	Forward-facing sensor mounted to the center of the roof	[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 above, the yaw angle (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 with Ground Following 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 Translation output port.

Specify offset — Specify offset from mounting location

off (default) | on

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.

Relative translation [X, Y, Z] (m) — Translation offset relative to mounting location

[0, 0, 0] (default) | real-valued 1-by-3 vector

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 (Vehicle Dynamics Blockset).

Example: [0,0,0.01]

Dependencies

To enable this parameter, select Specify offset.

Relative rotation [Roll, Pitch, Yaw] (deg) — Rotational offset relative to mounting location

[0, 0, 0] (default) | real-valued 1-by-3 vector

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 (Vehicle Dynamics Blockset).

Example: [0,0,10]

Dependencies

To enable this parameter, select Specify offset.

Parameters

Ray origins — Ray origin

zeros(10,3) (default) | real-valued N-by-3 array

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)

Ray directions — Normalized ray direction

ones(10,3) (default) | real-valued N-by-3 array

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)

Max ray lengths — Maximum total ray length

ones(10,1)*10 (default) | real-valued N-by-1 vector

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 — Number of bounces per ray

2 (default) | positive integer

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

Example: 0

Visualize trace line — Visualize ray traces

on (default) | off

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

Enable optimization — Enable optimization

on (default) | off

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 — Sample time

-1 (default) | positive scalar

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 R2024a