Simulation 3D Message Get

Retrieve data from Unreal Engine visualization environment

Since R2025a

• 

Libraries:
Vehicle Dynamics Blockset / Vehicle Scenarios / Sim3D / Sim3D Core
Aerospace Blockset / Animation / Simulation 3D
Simulink 3D Animation / Simulation 3D / Utilities

Description

The Simulation 3D Message Get block retrieves data from the Unreal Engine^® 3D visualization environment. In your model, ensure that the Simulation 3D Scene Configuration block is at the same level as the Simulation 3D Message Get block.

Tip

Verify that the Simulation 3D Scene Configuration block executes before the Simulation 3D Message Get block. That way, the Unreal Engine 3D visualization environment prepares the data before the Simulation 3D Message Get 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 Message Get — 1

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

Configure Scenes to Send Data

To use the block, you must configure scenes in the Unreal Engine environment to send data to the Simulink^® model:

1. Install the Customize Scenes in Unreal Engine for 3D Simulations.

2. In the Unreal^® Editor, follow these general workflows to send data to Simulink. For detailed information, see Get Started Communicating with the Unreal Engine Visualization Environment.

   Unreal Engine User	Workflow
   Blueprint	Instantiate the Sim3DSet actor that corresponds to the data type you want to send to the Simulink model. This example shows the Unreal Editor Sim3DSet data types. Specify an actor tag name that matches the Simulation 3D Message Get block Signal name parameter. Navigate to the Level Blueprint. Find the blueprint method for the Sim3DSet actor class based on the data type and size specified by the Simulation 3D Message Get block Data type and Message size parameters. For example, in Unreal Editor, this diagram shows that Write Array Boolean is the method for the Sim3DSetBoolean actor class that sends Boolean data type of array size 30. Compile and save the scene. Note By default, the Double Lane Change scene has a Sim3DSetBoolean actor with tag name NumOfConesHit.
   C++ class	Create a new actor class for the mesh or asset that you want the Simulink model to interact with. Derive it from ASim3dActor. In the new actor class: Declare a pointer to the signal name as a class field. Get the class tag. Create a signal writer and assign the pointer in the method Sim3dSetup. In the method Sim3dStep, invoke the WriteSimulation3DMessage function to write the data to the Simulink model. Delete the signal writer in the method Sim3dRelease of the actor.

   For more information about the Unreal Editor, see the Unreal Engine Documentation.

Ports

Output

ReadMsg — Data retrieved from scene

scalar | array

Data retrieved from the 3D visualization environment scene data. In the Unreal Engine environment, you can use the Sim3DSet class to configure scene actors to send data to the Simulink model.

Parameters

Signal name, SigName — Message signal name

mySignal (default)

Specifies the signal name in the 3D visualization environment. In the Unreal Engine environment, use the Sim3DSet actor class 'Tags' property located in the 'Details' pane.

For example, you can retrieve data from the double-lane change scene that indicates if cones are hit during a double-lane change maneuver. To retrieve cone hit data from the double-lane change scene, set this parameter to NumOfConesHit. In the double-lane change scene, the Sim3DSet actor class 'Tags' property is set to NumOfConesHit.

Data type, DataType — Message data type

double* | single | int8* | uint8* | int16* | uint16* | int32 | uint32* | boolean

3D visualization environment signal data type. The supported data types depend on the Unreal Engine workflow.

Workflow	Supported Data Types
Blueprint	single int32 Boolean
*C++ class	double single int8 uint8 int16 uint16 int32 uint32 Boolean

In the Unreal Engine environment, instantiate the Sim3DSet actor class for the data type that you want to send to the Simulink model. For example, you can retrieve data from the double-lane change scene that indicates if cones are hit during a double-lane change maneuver. To retrieve cone hit data from the double-lane change scene, set this parameter to boolean. In the double-lane change scene, the Sim3DSetBoolean actor class is instantiated to send the cone hit or miss boolean data.

Message size, MsgSize — Message dimension

[1 1] (default) | scalar | array

3D visualization environment signal dimension. In the Unreal Engine environment blueprint, set the input to the node of the Sim3DSet actor class to specify the dimensions of data that you want to send to the Simulink model.

For example, you can retrieve data from the double-lane change scene that indicates if cones are hit during a double-lane change maneuver. To retrieve cone hit data from the double-lane change scene, set this parameter to [2 15]. In the double-lane change scene, the input to the blueprint node for the Sim3DSetBoolean actor class is set to 30, the number of cones in the scene.

Sample time — Sample time

0.02 (default) | -1 | scalar

Sample time, in s. The graphics frame rate is the inverse of the sample time. If you set the sample time to -1, the block uses the sample time specified in the Simulation 3D Scene Configuration block.

Version History

Introduced in R2025a