UE4CtrlAPI Interface Documentation¶

Introduction¶

Brief: This file defines various data structures for communicating with the Unreal Engine 4 (UE4) simulation environment, enabling drone state requests, sensor data acquisition, camera parameter configuration, and SIL model data exchange.

Within the RflySim simulation platform, UE4 provides a high-fidelity 3D visualization and physical simulation environment. This module encapsulates all protocol structures required for data exchange with UE4, including drone pose and collision request data (CoptReqData, reqVeCrashData), object state queries (ObjReqData), visual sensor configuration (VisionSensorReqNew, CameraData), and PX4 SIL model interface data (PX4SILIntFloat). Through these structure definitions, developers can precisely construct and parse UE4 communication messages in a Python environment, enabling advanced functionalities such as sensor simulation, image acquisition, and hardware-in-the-loop testing within simulation scenarios.

Quick Start¶

Minimal working example; copy and modify minimal configuration to run.

# Import UE4CtrlAPI class for communication with RflySim3D/UE4
from RflySimSDK.ue import UE4CtrlAPI

# Initialize UE4 control interface, connect to local UE4 (default IP: 127.0.0.1)
# To connect to a remote PC, modify ip parameter, e.g., ip="192.168.1.100"
ue = UE4CtrlAPI(ip="127.0.0.1")

# Send command: display text "Hello RflySim" in UE4 for 5 seconds
# Available commands refer to documentation, e.g., map switching, camera control, etc.
ue.sendUE4Cmd('RflyShowTextTime "Hello RflySim" 5')

# Send command: switch map to ID 0 (default map)
ue.sendUE4Cmd("RflyChangeMapbyID 0")

Environment and Dependencies¶

Python Environment: >= 3.8.10
Dependencies: atexit, contextlib, copy, ctrl.IpManager, ctypes, cv2, math, numpy, os, platform, select, socket, struct, subprocess, sys, threading, time, typing, xml.etree.ElementTree
Prerequisites: Before calling this interface, the Unreal Engine simulation environment must be started, and RflySim3D or UE4 application must be running.

Core Interface Description¶

The module UE4CtrlAPI.py includes configuration variables, helper functions, and core business classes.

Global Constants and Enumerations¶

This section lists all globally accessible constants and enumeration definitions.

Standalone Constants¶

None

Global/Standalone Functions¶

None

`PX4SILIntFloat` Class¶

Data structure for SILints and SILFloats output to the CopterSim DLL model. This class encapsulates the integer and floating-point data transmission structure for the PX4 simulation interface, enabling SIL (Software In the Loop) simulation data exchange with CopterSim.

Data structure definition:

struct PX4SILIntFloat{
    int checksum;          // 1234567897
    int CopterID;
    int inSILInts[8];      // 8 integer inputs
    float inSILFLoats[20]; // 20 floating-point inputs
};

`init(iv=None)`¶

Function Description: Initializes a PX4SILIntFloat instance, setting the checksum, CopterID, and integer/float array data.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`any`	No	`None`	Input data used to initialize integer and float arrays. If an iterable is provided, the first 8 elements are mapped to `inSILInts`, and the next 20 elements are mapped to `inSILFLoats`

Returns:

PX4SILIntFloat instance object

Raises:

None

`reqVeCrashData` Class¶

UE4 UAV collision detection data structure, used to receive and store collision event information from the Unreal Engine 4 simulation environment. This structure includes the aircraft state at collision, collision object information, and spatial position data, suitable for collision analysis, incident replay, and safety validation scenarios.

`init(iv=None)`¶

Function Description: Initializes a collision data structure instance. Can be initialized from byte data or another instance of the same class; if no parameter is provided, an empty structure is created.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`bytes` \| `reqVeCrashData`	No	`None`	Initialization data, either a byte string or another instance of the same class

Returns:

reqVeCrashData instance object

Raises:

None

`CopyData(iv)`¶

Function Description: Copies collision data from an external data source into the current structure instance. Supports parsing and copying all fields from a byte string or another instance of the same class.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`bytes` \| `reqVeCrashData`	Yes	-	Data source, either a byte string or another instance of the same class

Returns:

None

Raises:

None

Example:

from RflySimSDK.ue import reqVeCrashData

# Create empty structure
crash_data = reqVeCrashData()

# Assume raw_bytes is raw data received via UDP
raw_bytes = b'...'  # Collision data packet from UE4
crash_data.CopyData(raw_bytes)

# Access collision information
print(f"Collision aircraft ID: {crash_data.copterID}")
print(f"Collision type: {crash_data.CrashType}")  # -2=ground, -1=static object, 0=no collision, >0=collided aircraft ID
print(f"Collision position: ({crash_data.CrashPos[0]}, {crash_data.CrashPos[1]}, {crash_data.CrashPos[2]})")

`CoptReqData` Class¶

Structure for storing UAV state request data, containing aircraft ID, position, attitude, geometric bounding box, and other information, totaling 80 bytes. Primarily used to transmit complete aircraft state data during communication with the UE4 engine.

`init(iv=None)`¶

Function Description: Initializes a CoptReqData instance, optionally populating data from a source object. Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`CoptReqData`	No	`None`	Source object for initialization; if `None`, creates an empty instance

Returns:

CoptReqData instance object

Raises:

None

Example:

# Create empty instance
data = CoptReqData()

# Create copy from existing data
new_data = CoptReqData(existing_data)

`CopyData(iv)`¶

Function Description: Copies data from the source object to the current instance, used for data synchronization or backup. Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`CoptReqData`	Yes	-	Source data object; all its field values will be copied to the current instance

Returns:

None

Raises:

None

Example:

source = CoptReqData()
source.CopterID = 1
source.PosUE = [0.0, 0.0, 0.0]

target = CoptReqData()
target.CopyData(source)  # Copies data from source to target

`CopyDataOld(iv)`¶

Function Description: Copies data from the source object to the current instance using the legacy format, ensuring compatibility with historical data structure parsing. Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`CoptReqData`	Yes	-	Source data object; fields are mapped and copied according to the legacy format

Returns:

None

Raises:

None

`ObjReqData` Class¶

Used to store and transmit the complete state information of objects in a UE4 scene, including position, orientation, geometric properties, and metadata. This class corresponds to the memory layout of a C struct and is commonly used for data exchange between the RflySim simulation system and the UE4 engine.

`init(iv=None)`¶

Function Description: Initializes an ObjReqData instance; optionally initializes from existing data. Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`ObjReqData` / `None`	No	`None`	Source data object; if `None`, creates an empty instance

Returns:

ObjReqData instance object

Raises:

None

`CopyData(iv)`¶

Function Description: Copies all field data from the source object to the current instance (new version format). Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`ObjReqData`	Yes	-	Source data object

Returns:

None

Raises:

None

`CopyDataOld(iv)`¶

Function Description: Copies all field data from the source object to the current instance (legacy format compatibility). Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`ObjReqData`	Yes	-	Source data object

Returns:

None

Raises:

None

Example:

# Create an empty instance and populate data
obj = ObjReqData()
obj.PosUE = [100.0, 200.0, 50.0]
obj.angEuler = [0.0, 0.0, 1.57]
obj.ObjName = b"TargetDrone\x00"

# Create a new instance by copying from an existing object
obj_copy = ObjReqData(obj)
# Or use the CopyData method
another_copy = ObjReqData()
another_copy.CopyData(obj)

`VisionSensorReqNew` Class¶

Used to send requests and set camera parameters to UE4. This class encapsulates the data structure for visual sensor requests, supporting camera parameter configuration, image acquisition, and sensor data exchange with the UE4 simulation environment.

`init(iv=None)`¶

Function Description: Initializes a VisionSensorReqNew instance, optionally initializing from existing data. Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`VisionSensorReqNew` / `None`	No	`None`	Source data object; if `None`, creates an empty instance

Returns:

VisionSensorReqNew instance object

Raises:

None

`CopyData(iv)`¶

Function Description: Copies all field data from the source object to the current instance. Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`VisionSensorReqNew`	Yes	-	Source data object

Returns:

None

Raises:

None

`CopyDataOld(iv)`¶

Function Description: Copies all field data from the source object to the current instance (legacy format compatibility). Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`VisionSensorReqNew`	Yes	-	Source data object

Returns:

None

Raises:

None

`setCamPara(camID, camType, camPos, camAngle, camFOV, camWidth, camHeight, camNear, camFar, camFrameRate, camAutoExposureSpeed, camExposureMin, camExposureMax, camCalib, camCalibFile, camDistortion, camDistortionFile, camLensFile, camNoise, camBlur, camRollingShutter, camMotionBlur)`¶

Function Description: Sets camera parameters, configuring the visual sensor's position, orientation, field of view, resolution, and other properties. Arguments (Args):

Parameter Name	Type	Required	Default	Description
`camID`	int	Yes	-	Camera ID
`camType`	int	Yes	-	Camera type
`camPos`	list[float]	Yes	-	Camera position [x, y, z]
`camAngle`	list[float]	Yes	-	Camera angle [roll, pitch, yaw]
`camFOV`	float	Yes	-	Field of view (degrees)
`camWidth`	int	Yes	-	Image width (pixels)
`camHeight`	int	Yes	-	Image height (pixels)
`camNear`	float	Yes	-	Near clipping plane
`camFar`	float	Yes	-	Far clipping plane
`camFrameRate`	float	Yes	-	Frame rate (fps)
`camAutoExposureSpeed`	float	Yes	-	Auto exposure speed
`camExposureMin`	float	Yes	-	Minimum exposure
`camExposureMax`	float	Yes	-	Maximum exposure
`camCalib`	int	Yes	-	Calibration flag
`camCalibFile`	str	Yes	-	Calibration file path
`camDistortion`	int	Yes	-	Distortion flag
`camDistortionFile`	str	Yes	-	Distortion file path
`camLensFile`	str	Yes	-	Lens file path
`camNoise`	float	Yes	-	Noise level
`camBlur`	float	Yes	-	Blur level
`camRollingShutter`	float	Yes	-	Rolling shutter effect
`camMotionBlur`	float	Yes	-	Motion blur level

Returns:

None

Raises:

None

`setCamParaSimple(camID, camType, camPos, camAngle, camFOV, camWidth, camHeight)`¶

Function Description: Sets simplified camera parameters, configuring the visual sensor's basic properties. Arguments (Args):

Parameter Name	Type	Required	Default	Description
`camID`	int	Yes	-	Camera ID
`camType`	int	Yes	-	Camera type
`camPos`	list[float]	Yes	-	Camera position [x, y, z]
`camAngle`	list[float]	Yes	-	Camera angle [roll, pitch, yaw]
`camFOV`	float	Yes	-	Field of view (degrees)
`camWidth`	int	Yes	-	Image width (pixels)
`camHeight`	int	Yes	-	Image height (pixels)

Returns:

None

Raises:

None

`getCamPara()`¶

Function Description: Retrieves the current camera parameter settings. Arguments (Args): None Returns:

Camera parameter dictionary

Raises:

None

`sendReq()`¶

Function Description: Sends the camera parameter request to the UE4 simulation environment. Arguments (Args): None Returns:

None

Raises:

None

`sendReqSimple()`¶

Function Description: Sends a simplified camera parameter request to the UE4 simulation environment. Arguments (Args): None Returns:

None

Raises:

None

`CameraData` Class¶

Camera data structure, used to receive and store image data and camera state information from the UE4 simulation environment. This structure includes image data, camera pose, timestamp, and other information, suitable for visual sensor simulation and image acquisition scenarios.

`init(iv=None)`¶

Function Description: Initializes a CameraData instance, optionally initializing from existing data. Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`CameraData` / `None`	No	`None`	Source data object; if `None`, creates an empty instance

Returns:

CameraData instance object

Raises:

None

`CopyData(iv)`¶

Function Description: Copies all field data from the source object to the current instance. Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`CameraData`	Yes	-	Source data object

Returns:

None

Raises:

None

`CopyDataOld(iv)`¶

Function Description: Copies all field data from the source object to the current instance (legacy format compatibility). Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`CameraData`	Yes	-	Source data object

Returns:

None

Raises:

None

`getImage()`¶

Function Description: Retrieves the image data from the camera data structure. Arguments (Args): None Returns:

Image data (numpy array)

Raises:

None

`getDepth()`¶

Function Description: Retrieves the depth data from the camera data structure. Arguments (Args): None Returns:

Depth data (numpy array)

Raises:

None

`getSegmentation()`¶

Function Description: Retrieves the segmentation data from the camera data structure. Arguments (Args): None Returns:

Segmentation data (numpy array)

Raises:

None

`UE4CtrlAPI` Class¶

Main control class for communicating with the UE4 simulation environment. This class provides all core functionalities for interacting with RflySim3D/UE4, including sending control commands, managing drone states, configuring cameras, handling collision detection, and managing scene objects.

`init(ip="127.0.0.1")`¶

Function Description: Initializes the UE4 control interface, establishing a UDP communication connection with the RflySim3D simulation environment.

Arguments (Args):

Parameter Name	Type	Default	Description
ip	str	"127.0.0.1"	IP address of the target PC, used to establish a UDP communication connection with RflySim3D

Returns: None Raises: None

`sendUE4Cmd(cmd, windowID=-1)`¶

Function Description: Sends a command to control the display style of RflySim3D. Available command strings take the form 'RflyShowTextTime "txt" time', supporting various display control functions including text display, map switching, camera control, and vehicle model operations.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
cmd	Any	Yes	None	Command string; for detailed command formats, refer to the function description
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Returns: None Raises: None

`fillList(data, inLen)`¶

Function Description: Internal helper method for populating list data. (No detailed documentation available.)

Arguments (Args):

Parameter Name	Type	Required	Default	Description
data	Any	Yes	None	Data to be filled
inLen	Any	Yes	None	Target length

Returns: None Raises: None

`sendUE4CmdNet(cmd)`¶

Function Description: Sends control commands to all RflySim3D instances over the local network using multicast address 224.0.0.10:20009, supporting up to 92 bytes of command data. Command types are automatically checked and converted: strings are encoded into byte sequences, and those exceeding 91 bytes are truncated. After sending the command, if it is a "RflyChangeMap" command, an additional 0.5-second wait is performed to ensure scene switching completes.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
cmd	Any	Yes	None	Command string or byte sequence; maximum length is 91 bytes

Returns: None Raises: None

`sendUE4LabelID(CopterID=0, Txt='', fontSize=30, RGB=[255, 0, 0], windowID=-1)`¶

Function Description: Sends a label ID display command to RflySim3D to display a text label on a specified aircraft.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
CopterID	Any	No	0	Target aircraft ID
Txt	Any	No	""	Text content to display
fontSize	Any	No	30	Font size
RGB	Any	No	[255, 0, 0]	Text color in [R, G, B] format, range 0–255
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Returns: None Raises: None

`sendUE4LabelMsg(CopterID=0, Txt='', fontSize=30, RGB=[255, 0, 0], dispTime=0, dispFlag=-1, windowID=-1)`¶

Function Description: Sends a label message display command to RflySim3D, supporting a more sophisticated message management mechanism. Message display behavior is jointly controlled by dispFlag and dispTime: - When dispFlag < 0 and dispTime >= 0, additive mode is used; - When dispFlag < 0 and dispTime < 0, all messages are cleared; - When dispFlag = 0 and dispTime >= 0, row 0 is updated; - When 1 <= dispFlag < 5, the corresponding row is updated; if dispTime < 0, the message is deleted; - If dispFlag exceeds the current number of messages, additive mode is automatically activated.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
CopterID	Any	No	0	Target aircraft ID; ≤0 indicates all aircraft
Txt	Any	No	""	Text content to display, maximum 120 bytes
fontSize	Any	No	30	Font size
RGB	Any	No	[255, 0, 0]	Text color in [R, G, B] format, range 0–255
dispTime	Any	No	0	Display duration in seconds; <0 for immediate disappearance, =0 for permanent display, >0 for disappearance after specified seconds
dispFlag	Any	No	-1	Display flag controlling message update mode
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Returns: None Raises: None

`sendUE4Attatch(CopterIDs, AttatchIDs, AttatchTypes, windowID=-1)`¶

Function Description: Sends a message to RflySim3D to attach one or more aircraft to other objects (supports up to 25 aircraft). Accepts three list-type arguments, each with a maximum length of 25. Attachment types include: 0—Normal mode, 1—Relative position but not relative attitude, 2—Relative position + yaw (not relative to pitch and roll), 3—Relative position + full attitude (pitch, roll, and yaw).

Arguments (Args):

Parameter Name	Type	Required	Default	Description
CopterIDs	Any	Yes	None	List of aircraft IDs, max length 25
AttatchIDs	Any	Yes	None	List of target object IDs to attach to, max length 25
AttatchTypes	Any	Yes	None	List of attachment types, values 0–3, max length 25
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Returns: None

Raises: None

`circle_traj(t, center=(0.0, 0.0), radius=1.0, W=5.0)`¶

Function Description: Generates a point on a circular trajectory; computes the coordinates on the circle based on the time parameter.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
t	float	Yes	None	Time (seconds)
center	Any	No	(0.0, 0.0)	Center coordinates of the circle (x_c, y_c)
radius	float	No	1.0	Radius (meters)
W	float	No	5.0	Trajectory period (seconds); default is 5 seconds per circle

Returns: Tuple (x, y), coordinates of the point on the circle

Raises: None

`sendUE4Pos(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)`¶

Function Description: Sends position and attitude information to RflySim3D to create a new 3D model or update the state of an existing one.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	Any	No	1	Aircraft ID
vehicleType	Any	No	3	Vehicle type
MotorRPMSMean	Any	No	0	Mean motor RPM
PosE	Any	No	[0, 0, 0]	Position in Earth-fixed frame [x, y, z] (meters, NED)
AngEuler	Any	No	[0, 0, 0]	Euler angles [roll, pitch, yaw] (radians)
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Returns: None

Raises: None

`sendUE4Pos2Ground(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)`¶

Function Description: Sends position and attitude information to RflySim3D to create or update a 3D model, ensuring the model remains always grounded. Uses checksum = 1

Parameter Name	Type	Required	Default	Description
copterID	Any	No	1	Aircraft ID
vehicleType	Any	No	3	Vehicle type
MotorRPMSMean	Any	No	0	Mean motor RPM
PosE	Any	No	[0, 0, 0]	Position in Earth coordinate frame [x, y, z] (meters, NED)
AngEuler	Any	No	[0, 0, 0]	Euler angles [roll, pitch, yaw] (radians)
Scale	Any	No	[1, 1, 1]	Scale factor [x, y, z]
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Returns: None Raises: None

`sendUE4PosFull(copterID, vehicleType, MotorRPMS=[0] * 8, VelE=[0, 0, 0], PosE=[0, 0, 0], RateB=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)`¶

Function Description: Sends complete position, attitude, and motion state information to RflySim3D for creating new 3D models or updating existing models with full state data. Includes full state information such as velocity, angular velocity, and motor RPMs.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	Any	Yes	None	Aircraft ID
vehicleType	Any	Yes	None	Vehicle type
MotorRPMS	Any	No	[0,0,0,0,0,0,0,0]	RPMs of 8 motors
VelE	Any	No	[0, 0, 0]	Velocity in Earth coordinate frame [Vx, Vy, Vz] (m/s, NED)
PosE	Any	No	[0, 0, 0]	Position in Earth coordinate frame [x, y, z] (m, NED)
RateB	Any	No	[0, 0, 0]	Angular rate in body frame [p, q, r] (rad/s)
AngEuler	Any	No	[0, 0, 0]	Euler angles [roll, pitch, yaw] (radians)
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Returns: None Raises: None

`sendUE4ExtAct(copterID=1, ActExt=[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], windowID=-1)`¶

Function Description: Sends extended actuation data to RflySim3D to control 16 additional floating-point parameters of the aircraft. Uses checksum = 1234567894 and includes a runtime timestamp along with 16 extended parameters.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	Any	No	1	Aircraft ID
ActExt	Any	No	[0,...0] (16 zeros)	16 extended actuation parameters
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Returns: None Raises: None

`sendUE4PosSimple(copterID, vehicleType, PWMs, VelE, PosE, AngEuler, runnedTime=-1, windowID=-1)`¶

Function Description: Sends simplified position and attitude information to RflySim3D, including a timestamp and PWM control signals. Used for creating new 3D models or updating existing models; fewer parameters than the full version, resulting in lower communication overhead.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	Any	Yes	None	Aircraft ID
vehicleType	Any	Yes	None	Vehicle type
PWMs	Any	Yes	None	8 PWM control signals
VelE	Any	Yes	None	Velocity in Earth coordinate system [Vx, Vy, Vz] (m/s, NED)
PosE	Any	Yes	None	Position in Earth coordinate system [x, y, z] (m, NED)
AngEuler	Any	Yes	None	Euler angles [roll, pitch, yaw] (radians)
runnedTime	Any	No	-1	Timestamp of elapsed time (seconds); -1 indicates using current time
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Returns: None Raises: None

`sendUE4PosNew(copterID=1, vehicleType=3, PosE=[0, 0, 0], AngEuler=[0, 0, 0], VelE=[0, 0, 0], PWMs=[0] * 8, runnedTime=-1, windowID=-1)`¶

Function Description: Sends position, attitude, and other information to RflySim3D to create new 3D models or update existing ones. This function constructs an SOut2SimulatorSimpleTime structure and transmits it via UDP to UE4.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	No	1	Aircraft/object ID
vehicleType	int	No	3	Vehicle type; 3 for quadcopter
PosE	list[float]	No	[0, 0, 0]	Position [x, y, z] in ENU coordinate system (meters)
AngEuler	list[float]	No	[0, 0, 0]	Euler angles [roll, pitch, yaw] (radians)
VelE	list[float]	No	[0, 0, 0]	Velocity [vx, vy, vz] in ENU coordinate system (m/s)
PWMs	list[float]	No	[0] * 8	Motor speeds / PWM values (up to 8 values)
runnedTime	float	No	-1	Current timestamp (seconds); -1 indicates using system current time
windowID	int	No	-1	Target RflySim3D window ID; -1 indicates broadcasting to all windows

Returns: None Raises: None

`sendUE4PosScale100(copterID, vehicleType, PosE, AngEuler, MotorRPMSMean, Scale, isFitGround=False, windowID=-1)`¶

Function Description: Sends position, attitude, scaling, and other information for up to 100 aircraft to RflySim3D in a single batch, enabling simultaneous creation or update of 100 3D models. This function constructs a Multi3DData100New structure and transmits it via UDP.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	list[int]	Yes	None	Array of 100 aircraft IDs (1–100); 0 indicates the model should not be displayed
vehicleType	list[int]	Yes	None	Array of 100 vehicle types; 3 for quadcopters
PosE	list[float]	Yes	None	300-element position array [x1,y1,z1,x2,y2,z2,...] (meters)
AngEuler

source = CoptReqData()
source.CopterID = 1
source.PosUE = [0.0, 0.0, 0.0]

target = CoptReqData()
target.CopyData(source)  # Copies data from source to target

`CopyDataOld(iv)`¶

Function Description: Copies data from the source object to the current instance using the legacy format, ensuring compatibility with historical data structure parsing.
Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`CoptReqData`	Yes	-	Source data object; fields are mapped and copied according to the legacy format

Return Value (Returns):

None

Exceptions (Raises):

None

`ObjReqData` Class¶

Used to store and transmit the complete state information of objects in a UE4 scene, including position, orientation, geometric properties, and metadata. This class corresponds to the memory layout of a C struct and is commonly used for data exchange between the RflySim simulation system and the UE4 engine.

`init(iv=None)`¶

Function Description: Initializes an ObjReqData instance; optionally initializes from existing data.
Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`ObjReqData` / `None`	No	`None`	Source data object; if `None`, creates an empty instance

Return Value (Returns):

ObjReqData instance object

Exceptions (Raises):

None

`CopyData(iv)`¶

Function Description: Copies all field data from the source object to the current instance (new version format).
Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`ObjReqData`	Yes	-	Source data object

Return Value (Returns):

None

Exceptions (Raises):

None

`CopyDataOld(iv)`¶

Function Description: Copies all field data from the source object to the current instance (legacy format compatibility).
Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`ObjReqData`	Yes	-	Source data object

Return Value (Returns):

None

Exceptions (Raises):

None

Example:

# Create an empty instance and populate data
obj = ObjReqData()
obj.PosUE = [100.0, 200.0, 50.0]
obj.angEuler = [0.0, 0.0, 1.57]
obj.ObjName = b"TargetDrone\x00"

# Create a new instance by copying from an existing object
obj_copy = ObjReqData(obj)
# Or use the CopyData method
another_copy = ObjReqData()
another_copy.CopyData(obj)

`VisionSensorReqNew` Class¶

This class corresponds to the C++ struct VisionSensorReq, used to send requests and set camera parameters to UE4. It contains complete configuration fields including data checksum, memory sequence ID, sensor type, target aircraft binding, image resolution, transport protocol, camera field of view, installation position and attitude.

`init(iv=None)`¶

Function Description: Initializes a vision sensor request object, optionally from an existing object for data copying. Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`VisionSensorReqNew`	No	`None`	Source object for initialization; if `None`, creates an instance with default parameters

Return Value (Returns):

VisionSensorReqNew instance object

Exceptions (Raises):

None

Example:

# Create a vision sensor request with default configuration
sensor_req = VisionSensorReqNew()

# Create a copy from an existing instance
existing_req = VisionSensorReqNew()
new_req = VisionSensorReqNew(existing_req)

`CopyData(iv)`¶

Function Description: Copies data fields from the specified vision sensor request object to the current instance. Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`VisionSensorReqNew`	Yes	-	Source vision sensor request object from which to copy all configuration data

Return Value (Returns):

None

Exceptions (Raises):

None

Example:

# Create two instances
source_sensor = VisionSensorReqNew()
target_sensor = VisionSensorReqNew()

# Copy data from source_sensor to target_sensor
target_sensor.CopyData(source_sensor)

`CameraData` Class¶

Represents the camera data structure, used to store camera metadata information, including camera sequence ID, type, resolution, field of view, position and attitude, timestamp, etc. The total size of this structure is 72 bytes.

`init(iv=None)`¶

Function Description: Initializes a camera data object. Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`CameraData`	No	`None`	Source object for data copying; if `None`, initializes with default values

Return Value (Returns):

CameraData instance object

Exceptions (Raises):

None

`CopyData(iv)`¶

Function Description: Copies data from the source object to the current object. Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`CameraData`	Yes	-	Source data object; its field values will be copied to the current object

Return Value (Returns):

None

Exceptions (Raises):

None

Example:

cam1 = CameraData()
cam1.SeqID = 1
cam1.TypeID = 0
cam1.DataHeight = 480
cam1.DataWidth = 640

cam2 = CameraData()
cam2.CopyData(cam1)  # cam2's field values are the same as cam1's

`CopyDataOld(iv)`¶

Function Description: Copies data from the source object to the current object using the legacy format. Arguments (Args):

Parameter Name	Type	Required	Default	Description
`iv`	`CameraData`	Yes	-	Source data object; data is copied using the legacy format

Return Value (Returns):

None

Exceptions (Raises):

None

`UE4CtrlAPI` Class¶

RflySim3D scene control and communication interface class. This class provides UDP communication capabilities with the UE4/UE5 simulation environment, supporting the transmission and reception of aircraft data, object data, and camera data, as well as sending scene control commands.

`init(ip="127.0.0.1")`¶

Function Description: Initializes a UE4CtrlAPI instance, establishing a communication connection with RflySim3D. Creates a UDP socket, initializes data storage vectors, sets control flags, and prepares an event mechanism for multi-threaded message processing.

Arguments (Args):

Parameter Name	Type	Default Value	Description
ip	str	"127.0.0.1"	IP address of the target PC, used to establish a UDP communication connection with RflySim3D

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4Cmd(cmd, windowID=-1)`¶

Function Description: Sends a command to control the display style of RflySim3D. Available command strings take the form 'RflyShowTextTime "txt" time', supporting various display control functions including text display, map switching, camera control, and vehicle model operations.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
cmd	Any	Yes	None	Command string; for detailed command formats, refer to the function description
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Return Value (Returns): None

Exceptions (Raises): None

`fillList(data, inLen)`¶

Function Description: Internal helper method for populating list data. (No detailed documentation available.)

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
data	Any	Yes	None	Data to be filled
inLen	Any	Yes	None	Target length

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4CmdNet(cmd)`¶

Function Description: Sends control commands to all RflySim3D instances over the local network using multicast address 224.0.0.10:20009, supporting up to 92 bytes of command data. Command types are automatically checked and converted: strings are encoded into byte sequences, and those exceeding 91 bytes are truncated. After sending the command, if it is a "RflyChangeMap" command, an additional 0.5-second wait is performed to ensure scene switching completes.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
cmd	Any	Yes	None	Command string or byte sequence; maximum length is 91 bytes

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4LabelID(CopterID=0, Txt='', fontSize=30, RGB=[255, 0, 0], windowID=-1)`¶

Function Description: Sends a label ID display command to RflySim3D to display a text label on a specified aircraft.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
CopterID	Any	No	0	Target aircraft ID
Txt	Any	No	""	Text content to display
fontSize	Any	No	30	Font size
RGB	Any	No	[255, 0, 0]	Text color in [R, G, B] format, range 0–255
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4LabelMsg(CopterID=0, Txt='', fontSize=30, RGB=[255, 0, 0], dispTime=0, dispFlag=-1, windowID=-1)`¶

Function Description: Sends a label message display command to RflySim3D, supporting a more sophisticated message management mechanism. Message display behavior is jointly controlled by dispFlag and dispTime:
- When dispFlag < 0 and dispTime >= 0, additive mode is used;
- When dispFlag < 0 and dispTime < 0, all messages are cleared;
- When dispFlag = 0 and dispTime >= 0, row 0 is updated;
- When 1 <= dispFlag < 5, the corresponding row is updated; if dispTime < 0, the message is deleted;
- If dispFlag exceeds the current number of messages, additive mode is automatically activated.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
CopterID	Any	No	0	Target aircraft ID; ≤0 indicates all aircraft
Txt	Any	No	""	Text content to display, maximum 120 bytes
fontSize	Any	No	30	Font size
RGB	Any	No	[255, 0, 0]	Text color in [R, G, B] format, range 0–255
dispTime	Any	No	0	Display duration in seconds; <0 for immediate disappearance, =0 for permanent display, >0 for disappearance after specified seconds
dispFlag	Any	No	-1	Display flag controlling message update mode
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4Attatch(CopterIDs, AttatchIDs, AttatchTypes, windowID=-1)`¶

Function Description: Sends a message to RflySim3D to attach one or more aircraft to other objects (supports up to 25 aircraft). Accepts three list-type arguments, each with a maximum length of 25. Attachment types include: 0—Normal mode, 1—Relative position but not relative attitude, 2—Relative position + yaw (not relative to pitch and roll), 3—Relative position + full attitude (pitch, roll, and yaw).

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
CopterIDs	Any	Yes	None	List of aircraft IDs, max length 25
AttatchIDs	Any	Yes	None	List of target object IDs to attach to, max length 25
AttatchTypes	Any	Yes	None	List of attachment types, values 0–3, max length 25
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Return Value (Returns): None

Exceptions (Raises): None

`circle_traj(t, center=(0.0, 0.0), radius=1.0, W=5.0)`¶

Function Description: Generates a point on a circular trajectory; computes the coordinates on the circle based on the time parameter.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
t	float	Yes	None	Time (seconds)
center	Any	No	(0.0, 0.0)	Center coordinates of the circle (x_c, y_c)
radius	float	No	1.0	Radius (meters)
W	float	No	5.0	Trajectory period (seconds); default is 5 seconds per circle

Return Value (Returns): Tuple (x, y), coordinates of the point on the circle

Exceptions (Raises): None

`sendUE4Pos(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)`¶

Function Description: Sends position and attitude information to RflySim3D to create a new 3D model or update the state of an existing one.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
copterID	Any	No	1	Aircraft ID
vehicleType	Any	No	3	Vehicle type
MotorRPMSMean	Any	No	0	Mean motor RPM
PosE	Any	No	[0, 0, 0]	Position in Earth-fixed frame [x, y, z] (meters, NED)
AngEuler	Any	No	[0, 0, 0]	Euler angles [roll, pitch, yaw] (radians)
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4Pos2Ground(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)`¶

Function Description: Sends position and attitude information to RflySim3D to create or update a 3D model, ensuring the model remains always grounded. Uses checksum = 1234567891 to instruct UE4 to generate an object that always stays on the ground.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
copterID	Any	No	1	Aircraft ID
vehicleType	Any	No	3	Vehicle type
MotorRPMSMean	Any	No	0	Mean motor RPM
PosE	Any	No	[0, 0, 0]	Position in Earth-fixed frame [x, y, z] (meters, NED)
AngEuler	Any	No	[0, 0, 0]	Euler angles [roll, pitch, yaw] (radians)
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4Destroy(copterID, windowID=-1)`¶

Function Description: Sends a command to RflySim3D to destroy a specified aircraft. When vehicleType == -3, the corresponding Copter is deleted based on the specified ID. Uses the sending logic of sendUE4PosNew.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
copterID	Any	Yes	None	ID of the aircraft to destroy
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4PosScale(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], Scale=[1, 1, 1], windowID=-1)`¶

Function Description: Sends position, attitude, and scaling information to RflySim3D to create or update a 3D model, with support for modifying the model's scale.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
copterID	Any	No	1	Aircraft ID
vehicleType	Any	No	3	Vehicle type
MotorRPMSMean	Any	No	0	Mean motor RPM
PosE	Any	No	[0, 0, 0]	Position in Earth-fixed frame [x, y, z] (meters, NED)
AngEuler	Any	No	[0, 0, 0]	Euler angles [roll, pitch, yaw] (radians)
Scale	Any	No	[1, 1, 1]	Scale factor [x, y, z]
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4PosScale2Ground(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], Scale=[1, 1, 1], windowID=-1)`¶

Function Description: Sends position, attitude, and scaling information to RflySim3D to create or update a 3D model, with support for modifying the model's scale, and ensures the model remains always grounded. Uses checksum = 1234567891 to instruct UE4 to generate an object that always stays on the ground.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	Any	No	1	Aircraft ID
vehicleType	Any	No	3	Vehicle type
MotorRPMSMean	Any	No	0	Mean motor RPM
PosE	Any	No	[0, 0, 0]	Position in Earth coordinate frame [x, y, z] (meters, NED)
AngEuler	Any	No	[0, 0, 0]	Euler angles [roll, pitch, yaw] (radians)
Scale	Any	No	[1, 1, 1]	Scale factor [x, y, z]
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Return Value (Returns): None
Exceptions (Raises): None

`sendUE4PosFull(copterID, vehicleType, MotorRPMS=[0] * 8, VelE=[0, 0, 0], PosE=[0, 0, 0], RateB=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)`¶

Function Description: Sends complete position, attitude, and motion state information to RflySim3D for creating new 3D models or updating existing models with full state data. Includes full state information such as velocity, angular velocity, and motor RPMs.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	Any	Yes	None	Aircraft ID
vehicleType	Any	Yes	None	Vehicle type
MotorRPMS	Any	No	[0,0,0,0,0,0,0,0]	RPMs of 8 motors
VelE	Any	No	[0, 0, 0]	Velocity in Earth coordinate frame [Vx, Vy, Vz] (m/s, NED)
PosE	Any	No	[0, 0, 0]	Position in Earth coordinate frame [x, y, z] (m, NED)
RateB	Any	No	[0, 0, 0]	Angular rate in body frame [p, q, r] (rad/s)
AngEuler	Any	No	[0, 0, 0]	Euler angles [roll, pitch, yaw] (radians)
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Return Value (Returns): None
Exceptions (Raises): None

`sendUE4ExtAct(copterID=1, ActExt=[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], windowID=-1)`¶

Function Description: Sends extended actuation data to RflySim3D to control 16 additional floating-point parameters of the aircraft. Uses checksum = 1234567894 and includes a runtime timestamp along with 16 extended parameters.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	Any	No	1	Aircraft ID
ActExt	Any	No	[0,...0] (16 zeros)	16 extended actuation parameters
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Return Value (Returns): None
Exceptions (Raises): None

`sendUE4PosSimple(copterID, vehicleType, PWMs, VelE, PosE, AngEuler, runnedTime=-1, windowID=-1)`¶

Function Description: Sends simplified position and attitude information to RflySim3D, including a timestamp and PWM control signals. Used for creating new 3D models or updating existing models; fewer parameters than the full version, resulting in lower communication overhead.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	Any	Yes	None	Aircraft ID
vehicleType	Any	Yes	None	Vehicle type
PWMs	Any	Yes	None	8 PWM control signals
VelE	Any	Yes	None	Velocity in Earth coordinate system [Vx, Vy, Vz] (m/s, NED)
PosE	Any	Yes	None	Position in Earth coordinate system [x, y, z] (m, NED)
AngEuler	Any	Yes	None	Euler angles [roll, pitch, yaw] (radians)
runnedTime	Any	No	-1	Timestamp of elapsed time (seconds); -1 indicates using current time
windowID	Any	No	-1	Target window ID; -1 indicates all windows

Return Value (Returns): None
Exceptions (Raises): None

`sendUE4PosNew(copterID=1, vehicleType=3, PosE=[0, 0, 0], AngEuler=[0, 0, 0], VelE=[0, 0, 0], PWMs=[0] * 8, runnedTime=-1, windowID=-1)`¶

Function Description: Sends position, attitude, and other information to RflySim3D to create new 3D models or update existing ones. This function constructs an SOut2SimulatorSimpleTime structure and transmits it via UDP to UE4.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	No	1	Aircraft/object ID
vehicleType	int	No	3	Vehicle type; 3 for quadcopter
PosE	list[float]	No	[0, 0, 0]	Position [x, y, z] in ENU coordinate system (meters)
AngEuler	list[float]	No	[0, 0, 0]	Euler angles [roll, pitch, yaw] (radians)
VelE	list[float]	No	[0, 0, 0]	Velocity [vx, vy, vz] in ENU coordinate system (m/s)
PWMs	list[float]	No	[0] * 8	Motor speeds / PWM values (up to 8 values)
runnedTime	float	No	-1	Current timestamp (seconds); -1 indicates using system current time
windowID	int	No	-1	Target RflySim3D window ID; -1 indicates broadcasting to all windows

Return Value (Returns): None
Exceptions (Raises): None

`sendUE4PosScale100(copterID, vehicleType, PosE, AngEuler, MotorRPMSMean, Scale, isFitGround=False, windowID=-1)`¶

Function Description: Sends position, attitude, scaling, and other information for up to 100 aircraft to RflySim3D in a single batch, enabling simultaneous creation or update of 100 3D models. This function constructs a Multi3DData100New structure and transmits it via UDP.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	list[int]	Yes	None	Array of 100 aircraft IDs (1–100); 0 indicates the model should not be displayed
vehicleType	list[int]	Yes	None	Array of 100 vehicle types; 3 for quadcopters
PosE	list[float]	Yes	None	300-element position array [x1,y1,z1,x2,y2,z2,...] (meters)
AngEuler	list[float]	Yes	None	300-element Euler angle array [r1,p1,y1,r2,p2,y2,...] (radians)
MotorRPMSMean	list[float]	Yes	None	100-element array of average motor speeds (RPM)
Scale	list[int]	Yes	None	300-element scaling array [sx1,sy1,sz1,sx2,sy2,sz2,...]; values equal actual dimensions × 100
isFitGround	bool	No	False	Whether to force aircraft to conform to ground level; when True, validation flag is set to 1234567891
windowID	int	No	-1	Target RflySim3D window ID; -1 indicates broadcasting to all windows

Return Value (Returns): None
Exceptions (Raises): None

`sendUE4PosScalePwm20(copterID, vehicleType, PosE, AngEuler, Scale, PWMs, isFitGround=False, windowID=-1)`¶

Function Description: Sends position, attitude, scaling, and PWM information for up to 20 aircraft to RflySim3D in a single batch, enabling simultaneous creation or update of 20 3D models. This function constructs a Multi3DData2New structure and transmits it via UDP.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	list[int]	Yes	None	Array of 20 aircraft IDs (1–20); 0 indicates the model should not be displayed
vehicleType	list[int]	Yes	None	Array of 20 vehicle types; 3 for quadcopters
PosE	list[float]	Yes	None	60-element position array [x1,y1,z1,x2,y2,z2,...] (meters)
AngEuler	list[float]	Yes	None	60-element Euler angle array [r1,p1,y1,r2,p2,y2,...] (radians)
Scale	list[int]	Yes	None	60-element scaling array [sx1,sy1,sz1,sx2,sy2,sz2,...]; values equal actual dimensions × 100
PWMs	list[float]	Yes	None	160-element PWM/motor speed array, corresponding to 8 motors for each of the 20 aircraft (RPM)
isFitGround	bool	No	False	Whether to force aircraft to conform to ground level; when True, validation flag is set to 1234567891
windowID	int	No	-1	Target RflySim3D window ID; -1 indicates broadcasting to all windows

Return Value (Returns): None
Exceptions (Raises): None

`getUE4Pos(CopterID=1)`¶

Function Description: Retrieves the position data of a specified aircraft in UE4. This method queries the internal data cache and returns the position information for the specified CopterID.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
CopterID	int	No	1	Target aircraft ID

Return Value (Returns): Position data of the specified aircraft; the exact format depends on the internal data structure definition.

Exceptions (Raises): None

`getUE4Data(CopterID=1)`¶

Function Description: Retrieves the complete data of a specified aircraft in UE4. This method queries the internal data cache and returns all relevant data for the specified CopterID, providing more comprehensive information than getUE4Pos.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
CopterID	int	No	1	Target aircraft ID

Return Value (Returns): Complete data of the specified aircraft; the exact format depends on the internal data structure definition.

Exceptions (Raises): None

`initUE4MsgRec()`¶

Function Description: Initializes the listening mechanism for receiving UDP data from UE4. Currently used primarily for listening to crash data. It creates a UDP receiving thread and starts listening on the specified port.

Arguments (Args): None

Return Value (Returns): None

Exceptions (Raises): None

`endUE4MsgRec()`¶

Function Description: Stops the UE4 message listener. Terminates the UDP receiving thread, cleans up related resources, and stops the message listening mechanism started by initUE4MsgRec.

Arguments (Args): None

Return Value (Returns): None

Exceptions (Raises): None

`UE4MsgRecLoop()`¶

Function Description: UE4 message listener blocking loop function. Listens on 224.0.0.10:20006 and local port 20006, processing messages returned by RflySim3D or CopterSim. It supports six message types:

CopterSimCrash (12 bytes): Collision detection data; returned by RflySim3D upon collision occurrence after collision detection mode is enabled via key 'P'.
PX4SILIntFloat (120 bytes): A composite data structure containing checksum, CopterID, integer array, and float array.
reqVeCrashData (160 bytes): Complete aircraft state data, including position, velocity, attitude, collision information, etc.
CameraData (56 bytes): Camera data; stored in self.CamDataVect upon reception.
CoptReqData (64 bytes): Target data associated with a copter_id; stored in self.CoptDataVect upon reception.
ObjReqData (96 bytes): Data for built-in scene objects; stored in self.ObjDataVect upon reception.

Received data can be retrieved using the getCamCoptObj function.

Arguments (Args): None

Return Value (Returns): None

Exceptions (Raises): None

`getCamCoptObj(type_id=1, objName=1)`¶

Function Description: Retrieves camera, target, or object data based on type and name. The meaning of objName varies depending on type_id:

type=0: Camera; objName corresponds to the camera's seqID
type=1: Manually created target with copter_id; objName corresponds to CopterID
type=2: Built-in scene object; objName corresponds to the object's name (string)

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
type_id	int	No	1	Request type: 0=Camera, 1=Target with copter_id, 2=Built-in scene object
objName	int/str	No	1	Target identifier: seqID for camera, CopterID for target, or name string for object

Return Value (Returns): Data object corresponding to the specified type; the exact format depends on type_id

Exceptions (Raises): None

`sendRflyShowTextTime(txt, time)`¶

Function Description: Sends a command to RflySim3D to display a specified text message for a given duration within the simulation environment.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
txt	str	Yes	None	Text content to be displayed
time	float	Yes	None	Duration for text display, in seconds

Return Value (Returns): None

Exceptions (Raises):

Exception Type	Description
TypeError	Raised when argument types are incorrect
ValueError	Raised when argument values are invalid

`reqCamCoptObj(type_id=1, objName=1, windowID=0)`¶

Function Description: Requests data for cameras, targets with copter_id, or scene-embedded objects from RflySim3D. The meaning of objName varies depending on type_id:

type=0: Camera; objName corresponds to the camera's seqID
type=1: Manually created target with copter_id; objName corresponds to CopterID
type=2: Scene-embedded object; objName corresponds to the object's name (string)

Internally invokes the RflyReqObjData(int opFlag, FString objName, FString colorflag) function command, where opFlag: 0=create camera, 1=create target corresponding to copter_id, 2=create object.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
type_id	int	No	1	Request type: 0=Camera, 1=Target with `copter_id`, 2=Scene-embedded object
objName	int/str	No	1	Target identifier: `seqID` for camera, `CopterID` for target, or object name string
windowID	int	No	0	Target RflySim3D window ID; default is window 0

Return Value (Returns): None

Exceptions (Raises): None

`reqCam(SeqIDList=[0], windowID=0)`¶

Function Description: Requests data for specified cameras from RflySim3D. After sending the request, RflySim3D periodically returns CameraData structures, which are stored in self.CamDataVect upon receipt and can be retrieved using getCamCoptObj.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
SeqIDList	list[int]	No	[0]	List of camera sequence IDs
windowID	int	No	0	Target RflySim3D window ID; default is window 0

Return Value (Returns): None

Exceptions (Raises): None

`reqCopt(CopterIDList=[0], windowID=0)`¶

Function Description: Requests data for specified targets with copter_id from RflySim3D. After sending the request, RflySim3D periodically returns CoptReqData structures, which are stored in self.CoptDataVect upon receipt and can be retrieved using getCamCoptObj.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
CopterIDList	list[int]	No	[0]	List of `copter_id` IDs
windowID	int	No	0	Target RflySim3D window ID; default is window 0

Return Value (Returns): None

Exceptions (Raises): None

`reqObj(ObjNameList=[''], windowID=0)`¶

Function Description: Requests data for scene-embedded objects from RflySim3D. After sending the request, RflySim3D periodically returns ObjReqData structures, which are stored in self.ObjDataVect upon receipt and can be retrieved using getCamCoptObj.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
ObjNameList	list[str]	No	['']	List of object names
windowID	int	No	0	Target RflySim3D window ID; default is window 0

Return Value (Returns): None

Exceptions (Raises): None

`SetUE4RadianceValue(UEObjectName, windows=-1)`¶

Function Description: Sets the radiance/luminance value of a specified object in UE4, used to adjust lighting or emissive effects of objects in the scene.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
UEObjectName	str	Yes	None	Name of the object in the UE4 scene
windows	int	No	-1	Target RflySim3D window ID; -1 indicates broadcasting to all windows

Return Value (Returns): None

Exceptions (Raises): None

`SetUE4RadianceValue__All(windows=-1)`¶

Function Description: Sets the radiance/luminance value for all windows.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
windows	int	No	-1	Window ID; -1 indicates all windows

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4SetStencilValueByActorName(Actorname, StencilValue, is_name_regex=False, windowID=-1)`¶

Function Description: Sets the stencil value (template buffer value) of the scene via Actor name, used for masking or contour extraction in post-processing.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
Actorname	str	Yes	None	Actor name
StencilValue	int	Yes	None	Stencil value (0–255)
is_name_regex	bool	No	False	Whether to use regex for name matching
windowID	int	No	-1	Window ID; -1 indicates all windows

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4SetStencilValueByMeshComponentName(Meshname, StencilValue, is_name_regex=False, windowID=-1)`¶

Function Description: Sets the stencil value of the scene via mesh component name, used for masking or contour extraction in post-processing.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
Meshname	str	Yes	None	Mesh component name
StencilValue	int	Yes	None	Stencil value (0–255)
is_name_regex	bool	No	False	Whether to use regex for name matching
windowID	int	No	-1	Window ID; -1 indicates all windows

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4SetStencilValueByCopterID(CopterID, StencilValue, windowID=-1)`¶

Function Description: Sets the stencil value of the corresponding Actor via CopterID (drone ID), used for masking or contour extraction in post-processing.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
CopterID	int	Yes	None	Drone ID
StencilValue	int	Yes	None	Stencil value (0–255)
windowID	int	No	-1	Window ID; -1 indicates all windows

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4VariableMessage(copterID, vehicleType, settingType, pointIndex, vehicleSetting, messageType, messageDatas, windowID=-1)`¶

Function Description: Sends a variable-length pipeline/line message for creating or modifying visualization objects such as pipes and lines in UE4. Supports operation types including create, modify, and delete, and allows setting properties such as pipe radius, transparency, and color.

Arguments (Args):

Parameter Name	Type	Required	Default Value	Description
copterID	int	Yes	None	Object ID, used to uniquely identify a pipeline/tube object
vehicleType	int	Yes	None	Object type (ClassID)
settingType	int	Yes	None	Edit type: 0 = add, 1 = modify, 2 = delete
pointIndex	list	Yes	None	Array of point indices: -1 = all points, 0 = no modification, other values = specific point indices
vehicleSetting	list	Yes	None	Parameter settings array (16 elements): [radius (m), opacity, emissive intensity, color R, G, B, A, UI visibility flag, ...]; -1 = retain original data, -2 = use default data
messageType	int	Yes	None	Message type: 0 = unknown, 1 = int32, 2 = float, 3 = string, 4 = Vector2D, 5 = Vector3D
messageDatas	list	Yes	None	Message content array; coordinate units are meters
windowID	int	No	-1	Window ID; -1 indicates all windows

Return Value (Returns): None

Exceptions (Raises): None

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	None	Object ID, used to uniquely identify a pipeline/tube object
vehicleType	int	Yes	None	Object type (ClassID)
settingType	int	Yes	None	Edit type: 0 = add, 1 = modify, 2 = delete
pointIndex	list	Yes	None	Array of point indices: -1 = all points, 0 = no modification, other values = specific point indices
vehicleSetting	list	Yes	None	Parameter settings array (16 elements): [radius (m), opacity, emissive intensity, color R, G, B, A, UI visibility flag, ...]; -1 = retain original data, -2 = use default data
messageType	int	Yes	None	Message type: 0 = unknown, 1 = int32, 2 = float, 3 = string, 4 = Vector2D, 5 = Vector3D
messageDatas	list	Yes	None	Message content array; coordinate units are meters
windowID	int	No	-1	Window ID; -1 indicates all windows

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4CreatePipelineMsg(copterID, settingParam, messageDatas)`¶

Function Description: Sends a pipeline creation message to create a new pipeline/tube object in UE4.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	None	Pipeline object ID
settingParam	list	Yes	None	Pipeline parameter settings array
messageDatas	list	Yes	None	Pipeline point coordinate data

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4CoverPipelineMsg(copterID, settingParam, messageDatas)`¶

Function Description: Sends a pipeline overwrite message to completely replace an existing pipeline/tube object with new data.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	None	Pipeline object ID
settingParam	list	Yes	None	Pipeline parameter settings array
messageDatas	list	Yes	None	Pipeline point coordinate data

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4AddPointToPipelineMsg(copterID, messageDatas)`¶

Function Description: Sends a message to append new points to an existing pipeline/tube object.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	None	Pipeline object ID
messageDatas	list	Yes	None	Point coordinate data to be appended

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4DeletePointMsg(copterID, pointIndexs)`¶

Function Description: Sends a message to delete specific points from a pipeline.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	None	Pipeline object ID
pointIndexs	list	Yes	None	Array of indices of points to be deleted

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4SetPipelineScaleMsg(copterID, pointIndexs, size)`¶

Function Description: Sends a message to set the pipeline thickness, modifying the radius/thickness of specified points.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	None	Pipeline object ID
pointIndexs	list	Yes	None	Array of point indices to be modified; -1 indicates all points
size	float	Yes	None	Pipeline radius in meters

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4SetPipelineDiaphaneityMsg(copterID, pointIndexs, diaphaneity)`¶

Function Description: Sends a message to set the pipeline transparency, modifying the material transparency of specified points.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	None	Pipeline object ID
pointIndexs	list	Yes	None	Array of point indices to be modified; -1 indicates all points
diaphaneity	float	Yes	None	Transparency value, typically in the range [0, 1]

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4SetPipelineLightMsg(copterID, pointIndexs, light)`¶

Function Description: Sends a message to set the pipeline emissive intensity, modifying the self-illumination effect of specified points.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	None	Pipeline object ID
pointIndexs	list	Yes	None	Array of point indices to be modified; -1 indicates all points
light	float	Yes	None	Emissive intensity value

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4SetPipelineColorMsg(copterID, pointIndexs, Color_R, Color_G, Color_B, Color_A)`¶

Function Description: Sends a message to set the pipeline color, modifying the material color (RGBA) of specified points.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	None	Pipeline object ID
pointIndexs	list	Yes	None	Array of point indices to be modified; -1 indicates all points
Color_R	float	Yes	None	Red channel value (0–1 or 0–255)
Color_G	float	Yes	None	Green channel value (0–1 or 0–255)
Color_B	float	Yes	None	Blue channel value (0–1 or 0–255)
Color_A	float	Yes	None	Alpha channel value (0–1 or 0–255)

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4SetPipelinePosMsg(copterID, pointIndexs, messageDatas)`¶

Function Description: Sends a message to set the position of pipeline points, modifying the spatial coordinates of specified points.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	None	Pipeline object ID
pointIndexs	list	Yes	None	Array of point indices to be modified
messageDatas	list	Yes	None	New point coordinate data in meters

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4SetWidgetVisble(copterID, isShowUI)`¶

Function Description: Sends a message to set widget visibility, controlling the display or hiding of UI widgets related to pipelines/lines.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	None	Pipeline/widget object ID
isShowUI	bool	Yes	None	Whether to show the UI widget; True to show, False to hide

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4RobotExtAct(copterID=1, ActExt=[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], windowID=-1)`¶

Function Description: Sends extended action control commands for the quadruped robot (robot dog) to the UE4 simulation environment. Control item activation is managed via a TypeMask bitmask, supporting multiple control modes including action commands, obstacle avoidance settings, target position, attitude control, and velocity vectors.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	No	1	CopterID identifier of the robot dog
ActExt	list[float]	No	[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]	Extended action parameter array, 16 elements total: 0.TypeMask (bitmask) 1.Robot dog action command (1 stand up, 2 jump, etc.) 2.Obstacle avoidance radius 3-5.Destination position x,y,z 6-8.Robot dog's own Roll, Pitch, Yaw 9-11.Robot dog forward vector X,Y,Z 12.Robot dog speed setting 13.Coordinate system used (1:NED, 2:FRD)
windowID	int	No	-1	Target window ID; -1 indicates all windows

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4MassMovement(robotDogID, childUAVID, isCombined)`¶

Function Description: Sends a command to combine or separate a robot dog and a UAV, enabling coordinated motion control of a UAV carried by the robot dog.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
robotDogID	int	Yes	-	ID of the robot dog
childUAVID	int	Yes	-	ID of the child UAV (the one being carried)
isCombined	bool/int	Yes	-	Whether to combine; True/1 means combine, False/0 means separate

Return Value (Returns): None

Exceptions (Raises): None

`sendDogPosENoAltYaw(copterID, pos_x, pos_y, yaw)`¶

Function Description: Sends horizontal position (XY plane) and yaw angle control commands for the robot dog, while maintaining constant altitude.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	-	CopterID of the robot dog
pos_x	float	Yes	-	Target X coordinate (ENU coordinate system, unit: meters)
pos_y	float	Yes	-	Target Y coordinate (ENU coordinate system, unit: meters)
yaw	float	Yes	-	Target yaw angle (unit: radians)

Return Value (Returns): None

Exceptions (Raises): None

`sendDogPosENoAlt(copterID, pos_x, pos_y)`¶

Function Description: Sends horizontal position (XY plane) control commands for the robot dog, while maintaining constant altitude and yaw angle.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	-	CopterID of the robot dog
pos_x	float	Yes	-	Target X coordinate (ENU coordinate system, unit: meters)
pos_y	float	Yes	-	Target Y coordinate (ENU coordinate system, unit: meters)

Return Value (Returns): None

Exceptions (Raises): None

`sendDogRateNoAltYaw(copterID, yaw_rate, speed_x, speed_y, axis)`¶

Function Description: Sends rate control commands for the robot dog (yaw rate + horizontal velocity), while maintaining constant altitude.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	-	CopterID of the robot dog
yaw_rate	float	Yes	-	Yaw rate (unit: radians/second)
speed_x	float	Yes	-	Velocity in X direction (unit: meters/second)
speed_y	float	Yes	-	Velocity in Y direction (unit: meters/second)
axis	int	Yes	-	Coordinate system selection (1: NED, 2: FRD/body-fixed frame)

Return Value (Returns): None

Exceptions (Raises): None

`sendDogVelENoAltYaw(copterID, yaw, speed_x, speed_y, axis)`¶

Function Description: Sends velocity and feedforward yaw angle control commands for the robot dog, while maintaining constant altitude.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	-	CopterID of the robot dog
yaw	float	Yes	-	Target yaw angle (unit: radians)
speed_x	float	Yes	-	Velocity in X direction (unit: meters/second)
speed_y	float	Yes	-	Velocity in Y direction (unit: meters/second)
axis	int	Yes	-	Coordinate system selection (1: NED, 2: FRD/body-fixed frame)

Return Value (Returns): None

Exceptions (Raises): None

`sendDogVelENoAlt(copterID, speed_x, speed_y, axis)`¶

Function Description: Sends horizontal velocity control commands for the robot dog, while maintaining constant altitude and yaw angle.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	-	CopterID of the robot dog
speed_x	float	Yes	-	Velocity in X direction (unit: m/s)
speed_y	float	Yes	-	Velocity in Y direction (unit: m/s)
axis	int	Yes	-	Coordinate system selection (1: NED, 2: FRD/body-fixed frame)

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4DogSpeed(copterID, speed)`¶

Function Description: Sends a command to set the scalar motion speed of the robot dog.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	-	CopterID of the robot dog
speed	float	Yes	-	Target speed value (unit: m/s)

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4DogObstacleAvoidance(copterID, radius)`¶

Function Description: Sends a command to set the obstacle avoidance radius of the robot dog, enabling or disabling autonomous obstacle avoidance.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	-	CopterID of the robot dog
radius	float	Yes	-	Obstacle avoidance radius (unit: m); obstacle avoidance is disabled when radius < 0; default is 0.05

Return Value (Returns): None

Exceptions (Raises): None

`sendUE4DogPlayAction(copterID, actionNum)`¶

Function Description: Sends a command to play a predefined action of the robot dog, triggering a specific behavioral motion.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
copterID	int	Yes	-	CopterID of the robot dog
actionNum	int	Yes	-	Action number; valid values: 1: Damp, 2: BalanceStand, 3: StopMove, 4: PStandUp, 5: StandDown, 6: RecoveryStand, 7: Sit, 8: RiseSit, 9: SwitchGait, 10: BodyHeight, 11: FootRaiseHeight, 12: SpeedLevel, 13: Hello, 14: Stretch, 15: SwitchJoystick, 16: ContinuousGait, 17: Wallow, 18: Pose, 19: Scrape, 20: FrontFlip, 21: FrontJump, 22: FrontPounce, 23: Dance

Return Value (Returns): None

Exceptions (Raises): None

`startMulticastListener()`¶

Function Description: Starts the multicast listener to receive multicast data from the UE4 simulation environment.

Arguments (Args): None

Return Value (Returns): None

Exceptions (Raises): None

`stopMulticastListener()`¶

Function Description: Stops the multicast listener, terminating the reception of multicast data from the UE4 simulation environment.

Arguments (Args): None

Return Value (Returns): None

Exceptions (Raises): None

`getRflyStatusMap()`¶

Function Description: Retrieves the RflySim simulation status map, containing the current simulation runtime status and related information.

Arguments (Args): None

Return Value (Returns): Returns a dictionary storing various status information in key-value pairs.

Exceptions (Raises): None

`getRflyIP(user)`¶

Function Description: Retrieves the RflySim simulation IP address for a specified user.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
user	str	Yes	-	User identifier

Return Value (Returns): Returns the IP address string corresponding to the specified user.

Exceptions (Raises): None

`getRflyStartTime(user)`¶

Function Description: Retrieves the RflySim simulation start time for a specified user.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
user	str	Yes	-	User identifier

Return Value (Returns): Returns the simulation start timestamp (unit: seconds).

Exceptions (Raises): None

`getRflyMapName(user)`¶

Function Description: Retrieves the RflySim map name for a specified user.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
user	Any	Yes	-	Target user identifier

Return Value (Returns): Map name

Exceptions (Raises): None

`getRflyHeartbeat(user)`¶

Function Description: Retrieves the RflySim heartbeat status for a specified user.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
user	Any	Yes	-	Target user identifier

Return Value (Returns): Heartbeat status

Exceptions (Raises): None

`getLocalUserName()`¶

Function Description: Retrieves the local username.

Arguments (Args): None

Return Value (Returns): Local username

Exceptions (Raises): None

`getCurIP()`¶

Function Description: Retrieves the current IP address.

Arguments (Args): None

Return Value (Returns): Current IP address

Exceptions (Raises): None

`getCurMapName()`¶

Function Description: Retrieves the current map name.

Arguments (Args): None

Return Value (Returns): Current map name

Exceptions (Raises): None

`getCurStartTime()`¶

Function Description: Retrieves the current startup time.

Arguments (Args): None

Return Value (Returns): Current startup time

Exceptions (Raises): None

`getCurHeartbeat()`¶

Function Description: Retrieves the current heartbeat status.

Arguments (Args): None

Return Value (Returns): Current heartbeat status

Exceptions (Raises): None

`getAllIPAndUserName()`¶

Function Description: Retrieves all IP addresses and corresponding usernames.

Arguments (Args): None

Return Value (Returns): Mapping of all IP addresses and usernames

Exceptions (Raises): None

`getAllUEMaps(is_ue5=False)`¶

Function Description: Retrieves all valid map names (.umap files) from the Content directory of the specified UE project. Automatically excludes maps starting with '_' or containing 'LogicMap' in their name.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
is_ue5	bool	No	False	Whether it is a UE5 project

Return Value (Returns): List of valid map names

Exceptions (Raises): None

`getAllUECopters(is_ue5=False, sort_by_custom=True)`¶

Function Description: Retrieves all placeable Copter entries in the current UE/UE5 project. This interface traverses XML resources under the project Content and plugin Content, extracts fields such as MeshClass and Name, processes them according to rules, and returns the result.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
is_ue5	bool	No	False	Whether to read according to UE5 project paths and resource rules
sort_by_custom	bool	No	True	Whether to sort by custom rules; when False, sorts by `ClassID`

Return Value (Returns): List of placeable Copter entries, each element typically a dictionary containing name, category, class ID, and other information.

Exceptions (Raises): None

`getAllUEVehicles(is_ue5=False, sort_by_custom=True)`¶

Function Description: Retrieves all vehicle entries in the current UE/UE5 project. This interface first reads the list of vehicle names, then filters vehicle-related XML items from the original resource list.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
is_ue5	bool	No	False	Whether to read according to UE5 project path and resource rules
sort_by_custom	bool	No	True	Whether to sort by custom rules; when False, sort by `ClassID`

Returns: A list of vehicle entries, each element typically a dictionary containing name, category, ClassID, and other information.

Raises: None

`getAllUEItems(is_ue5=False, sort_by_custom=True)`¶

Function Description: Retrieves all placeable items other than vehicles in the current UE/UE5 project. This interface traverses .xml files under the project Content and plugin Content directories, excludes items in the vehicle name list, and processes categories and sorting according to predefined rules.

Arguments (Args):

Parameter Name	Type	Required	Default	Description
is_ue5	bool	No	False	Whether it is a UE5 project
sort_by_custom	bool	No	True	Whether to sort by custom rules; when False, sort by `ClassID`

Returns: A list of placeable items other than vehicles, each element typically a dictionary containing name, category, ClassID, and other information.

Raises: None

Advanced Usage Examples¶

Demonstrates complex combined scenarios (e.g., multi-type collaboration, asynchronous control, batch operations)

from RflySimSDK.ue import UE4CtrlAPI, VisionSensorReqNew, CameraData
import time
import threading

# Initialize UE4 control API
ue = UE4CtrlAPI()

# Batch create multiple drones and assign circular trajectories
def batch_create_drones(count, center_pos, radius, height):
    """Batch create drones and assign circular formation trajectories"""
    drones = []
    for i in range(count):
        angle = (2 * 3.14159 * i) / count
        drone_id = 100 + i  # Starting ID

        # Compute target position
        target_x = center_pos[0] + radius * __import__('math').cos(angle)
        target_y = center_pos[1] + radius * __import__('math').sin(angle)

        # Send initial position to ground
        ue.sendUE4Pos2Ground(drone_id, 1, 
                           [target_x, target_y, height, 0, 0, 0])
        drones.append({
            'id': drone_id,
            'angle': angle,
            'radius': radius
        })
    return drones

# Asynchronous vision sensor data acquisition
def async_vision_sensor(sensor_id, callback):
    """Asynchronously fetch vision sensor data"""
    sensor = VisionSensorReqNew()

    def fetch_data():
        while True:
            # Copy latest data
            sensor.CopyData()
            callback(sensor_id, sensor)
            time.sleep(0.033)  # 30Hz refresh rate

    thread = threading.Thread(target=fetch_data)
    thread.daemon = True
    thread.start()
    return thread

# Complex scenario: Formation flight + dynamic obstacle avoidance + visual tracking
def complex_scenario():
    # 1. Batch create 6 drones in a circular formation
    formation = batch_create_drones(
        count=6, 
        center_pos=[0, 0, 0], 
        radius=50, 
        height=30
    )

    # 2. Add dynamic circular trajectories to the formation
    for drone in formation:
        ue.circle_traj(
            drone['id'], 
            center=[0, 0, 30], 
            radius=drone['radius'], 
            speed=10, 
            height=30
        )

    # 3. Asynchronously start visual sensor for target tracking
    def on_vision_data(sensor_id, data):
        # Process vision data and dynamically adjust the formation
        print(f"Sensor {sensor_id} captured frame")

    async_vision_sensor(201, on_vision_data)

    # 4. Dynamic destruction and reconstruction (simulating fault recovery)
    time.sleep(10)
    ue.sendUE4Destroy(102)  # Destroy drone #2
    time.sleep(2)
    ue.sendUE4Pos2Ground(102, 1, [30, 30, 30, 0, 0, 0])  # Reconstruct

# Execute the complex scenario
if __name__ == "__main__":
    complex_scenario()

Notes and Pitfall Avoidance Guide¶

ID Conflict Management: The copID parameter in methods such as sendUE4Pos and sendUE4Pos2Ground must be globally unique. Reusing the same ID for different positions will cause object flickering or abnormal control in UE4. It is recommended to establish an ID allocation table (e.g., 100–199 for multirotors, 200–299 for fixed-wing aircraft).
Coordinate System Confusion: sendUE4Pos uses the NED (North-East-Down) coordinate system, whereas sendUE4Pos2Ground forces the height to zero relative to the ground. Mixing these two within circle_traj will result in incorrect height calculations. It is recommended to consistently use sendUE4Pos throughout and manually implement ground collision detection.
Asynchronous Data Race: VisionSensorReqNew.CopyData() and CameraData.CopyData() are not thread-safe. Concurrent calls across threads may cause memory alignment errors. Mutex locks must be used for protection, or CopyDataOld can be used as a fallback to retrieve cached data from the previous frame.
Uncontrolled Object Lifecycle: sendUE4Destroy only destroys the UE4 visual object and does not clean up lingering CoptReqData or ObjReqData instances on the Python side. Long-running simulations will suffer from memory leaks. It is recommended to implement an object pool and explicitly call del or reconstruct the UE4CtrlAPI instance.
Network Timeout Blind Spot: sendUE4CmdNet relies on UDP transmission without acknowledgment. If the UE4 side is not running or firewall rules block the traffic, the call will fail silently. In production environments, this must be paired with reqVeCrashData or a custom heartbeat detection mechanism. Upon timeout, a reconnection logic should be triggered instead of continuing to queue commands.

Changelog¶

2026-04-10: Added interfaces for retrieving the UE map and list of placeable items.
2026-03-06: Added interface for overriding pipe creation.
2026-03-03: feat: SDK added IP handling mechanism to support local deployment on cloud.
2026-03-02: Added interface to delete a copter by ID.
2026-02-28: Added API to toggle visibility of waypoint ID labels in the UI.
2026-01-20: Fixed multicast interface and WSL environment bugs in UE4CtrlAPI.
2026-01-14: Modified multicast port.
2026-01-06: Added new interfaces for multicast-based IP retrieval and retrieving the RflySim-opened map.
2025-12-18: Added new UE control interfaces.
2025-09-11: fix: Added support for port reuse on Linux.
2025-08-19: fix: Updated vision and UE interfaces.
2025-07-14: fix
2025-07-11: fix
2024-07-30: Added gimbal interface documentation.
2024-07-10: Integrated interface content used by the gimbal program.

UE4CtrlAPI Interface Documentation¶

Introduction¶

Quick Start¶

Environment and Dependencies¶

Core Interface Description¶

Global Constants and Enumerations¶

Standalone Constants¶

Global/Standalone Functions¶

PX4SILIntFloat Class¶

__init__(iv=None)¶

reqVeCrashData Class¶

__init__(iv=None)¶

CopyData(iv)¶

CoptReqData Class¶

__init__(iv=None)¶

CopyData(iv)¶

CopyDataOld(iv)¶

ObjReqData Class¶

__init__(iv=None)¶

CopyData(iv)¶

CopyDataOld(iv)¶

VisionSensorReqNew Class¶

__init__(iv=None)¶

CopyData(iv)¶

CopyDataOld(iv)¶

setCamPara(camID, camType, camPos, camAngle, camFOV, camWidth, camHeight, camNear, camFar, camFrameRate, camAutoExposureSpeed, camExposureMin, camExposureMax, camCalib, camCalibFile, camDistortion, camDistortionFile, camLensFile, camNoise, camBlur, camRollingShutter, camMotionBlur)¶

setCamParaSimple(camID, camType, camPos, camAngle, camFOV, camWidth, camHeight)¶

getCamPara()¶

sendReq()¶

sendReqSimple()¶

CameraData Class¶

__init__(iv=None)¶

CopyData(iv)¶

CopyDataOld(iv)¶

getImage()¶

getDepth()¶

getSegmentation()¶

UE4CtrlAPI Class¶

__init__(ip="127.0.0.1")¶

sendUE4Cmd(cmd, windowID=-1)¶

fillList(data, inLen)¶

sendUE4CmdNet(cmd)¶

sendUE4LabelID(CopterID=0, Txt='', fontSize=30, RGB=[255, 0, 0], windowID=-1)¶

sendUE4LabelMsg(CopterID=0, Txt='', fontSize=30, RGB=[255, 0, 0], dispTime=0, dispFlag=-1, windowID=-1)¶

sendUE4Attatch(CopterIDs, AttatchIDs, AttatchTypes, windowID=-1)¶

circle_traj(t, center=(0.0, 0.0), radius=1.0, W=5.0)¶

sendUE4Pos(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)¶

sendUE4Pos2Ground(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)¶

sendUE4PosFull(copterID, vehicleType, MotorRPMS=[0] * 8, VelE=[0, 0, 0], PosE=[0, 0, 0], RateB=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)¶

sendUE4ExtAct(copterID=1, ActExt=[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], windowID=-1)¶

sendUE4PosSimple(copterID, vehicleType, PWMs, VelE, PosE, AngEuler, runnedTime=-1, windowID=-1)¶

sendUE4PosNew(copterID=1, vehicleType=3, PosE=[0, 0, 0], AngEuler=[0, 0, 0], VelE=[0, 0, 0], PWMs=[0] * 8, runnedTime=-1, windowID=-1)¶

sendUE4PosScale100(copterID, vehicleType, PosE, AngEuler, MotorRPMSMean, Scale, isFitGround=False, windowID=-1)¶

CopyDataOld(iv)¶

ObjReqData Class¶

__init__(iv=None)¶

CopyData(iv)¶

CopyDataOld(iv)¶

VisionSensorReqNew Class¶

__init__(iv=None)¶

CopyData(iv)¶

CameraData Class¶

__init__(iv=None)¶

CopyData(iv)¶

CopyDataOld(iv)¶

UE4CtrlAPI Class¶

__init__(ip="127.0.0.1")¶

sendUE4Cmd(cmd, windowID=-1)¶

fillList(data, inLen)¶

sendUE4CmdNet(cmd)¶

sendUE4LabelID(CopterID=0, Txt='', fontSize=30, RGB=[255, 0, 0], windowID=-1)¶

sendUE4LabelMsg(CopterID=0, Txt='', fontSize=30, RGB=[255, 0, 0], dispTime=0, dispFlag=-1, windowID=-1)¶

sendUE4Attatch(CopterIDs, AttatchIDs, AttatchTypes, windowID=-1)¶

circle_traj(t, center=(0.0, 0.0), radius=1.0, W=5.0)¶

sendUE4Pos(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)¶

sendUE4Pos2Ground(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)¶

sendUE4Destroy(copterID, windowID=-1)¶

sendUE4PosScale(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], Scale=[1, 1, 1], windowID=-1)¶

sendUE4PosScale2Ground(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], Scale=[1, 1, 1], windowID=-1)¶

sendUE4PosFull(copterID, vehicleType, MotorRPMS=[0] * 8, VelE=[0, 0, 0], PosE=[0, 0, 0], RateB=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)¶

`PX4SILIntFloat` Class¶

`init(iv=None)`¶

`reqVeCrashData` Class¶

`init(iv=None)`¶

`CopyData(iv)`¶

`CoptReqData` Class¶

`init(iv=None)`¶

`CopyData(iv)`¶

`CopyDataOld(iv)`¶

`ObjReqData` Class¶

`init(iv=None)`¶

`CopyData(iv)`¶

`CopyDataOld(iv)`¶

`VisionSensorReqNew` Class¶

`init(iv=None)`¶

`CopyData(iv)`¶

`CopyDataOld(iv)`¶

`setCamPara(camID, camType, camPos, camAngle, camFOV, camWidth, camHeight, camNear, camFar, camFrameRate, camAutoExposureSpeed, camExposureMin, camExposureMax, camCalib, camCalibFile, camDistortion, camDistortionFile, camLensFile, camNoise, camBlur, camRollingShutter, camMotionBlur)`¶

`setCamParaSimple(camID, camType, camPos, camAngle, camFOV, camWidth, camHeight)`¶

`getCamPara()`¶

`sendReq()`¶

`sendReqSimple()`¶

`CameraData` Class¶

`init(iv=None)`¶

`CopyData(iv)`¶

`CopyDataOld(iv)`¶

`getImage()`¶

`getDepth()`¶

`getSegmentation()`¶

`UE4CtrlAPI` Class¶

`init(ip="127.0.0.1")`¶

`sendUE4Cmd(cmd, windowID=-1)`¶

`fillList(data, inLen)`¶

`sendUE4CmdNet(cmd)`¶

`sendUE4LabelID(CopterID=0, Txt='', fontSize=30, RGB=[255, 0, 0], windowID=-1)`¶

`sendUE4LabelMsg(CopterID=0, Txt='', fontSize=30, RGB=[255, 0, 0], dispTime=0, dispFlag=-1, windowID=-1)`¶

`sendUE4Attatch(CopterIDs, AttatchIDs, AttatchTypes, windowID=-1)`¶

`circle_traj(t, center=(0.0, 0.0), radius=1.0, W=5.0)`¶

`sendUE4Pos(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)`¶

`sendUE4Pos2Ground(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)`¶

`sendUE4PosFull(copterID, vehicleType, MotorRPMS=[0] * 8, VelE=[0, 0, 0], PosE=[0, 0, 0], RateB=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)`¶

`sendUE4ExtAct(copterID=1, ActExt=[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], windowID=-1)`¶

`sendUE4PosSimple(copterID, vehicleType, PWMs, VelE, PosE, AngEuler, runnedTime=-1, windowID=-1)`¶

`sendUE4PosNew(copterID=1, vehicleType=3, PosE=[0, 0, 0], AngEuler=[0, 0, 0], VelE=[0, 0, 0], PWMs=[0] * 8, runnedTime=-1, windowID=-1)`¶

`sendUE4PosScale100(copterID, vehicleType, PosE, AngEuler, MotorRPMSMean, Scale, isFitGround=False, windowID=-1)`¶

`CopyDataOld(iv)`¶

`ObjReqData` Class¶

`init(iv=None)`¶

`CopyData(iv)`¶

`CopyDataOld(iv)`¶

`VisionSensorReqNew` Class¶

`init(iv=None)`¶

`CopyData(iv)`¶

`CameraData` Class¶

`init(iv=None)`¶

`CopyData(iv)`¶

`CopyDataOld(iv)`¶

`UE4CtrlAPI` Class¶

`init(ip="127.0.0.1")`¶

`sendUE4Cmd(cmd, windowID=-1)`¶

`fillList(data, inLen)`¶

`sendUE4CmdNet(cmd)`¶

`sendUE4LabelID(CopterID=0, Txt='', fontSize=30, RGB=[255, 0, 0], windowID=-1)`¶

`sendUE4LabelMsg(CopterID=0, Txt='', fontSize=30, RGB=[255, 0, 0], dispTime=0, dispFlag=-1, windowID=-1)`¶

`sendUE4Attatch(CopterIDs, AttatchIDs, AttatchTypes, windowID=-1)`¶

`circle_traj(t, center=(0.0, 0.0), radius=1.0, W=5.0)`¶

`sendUE4Pos(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)`¶

`sendUE4Pos2Ground(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)`¶

`sendUE4Destroy(copterID, windowID=-1)`¶

`sendUE4PosScale(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], Scale=[1, 1, 1], windowID=-1)`¶

`sendUE4PosScale2Ground(copterID=1, vehicleType=3, MotorRPMSMean=0, PosE=[0, 0, 0], AngEuler=[0, 0, 0], Scale=[1, 1, 1], windowID=-1)`¶

`sendUE4PosFull(copterID, vehicleType, MotorRPMS=[0] * 8, VelE=[0, 0, 0], PosE=[0, 0, 0], RateB=[0, 0, 0], AngEuler=[0, 0, 0], windowID=-1)`¶

`sendUE4ExtAct(copterID=1, ActExt=[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], windowID=-1)`¶

`sendUE4PosSimple(copterID, vehicleType, PWMs, VelE, PosE, AngEuler, runnedTime=-1, windowID=-1)`¶

`sendUE4PosNew(copterID=1, vehicleType=3, PosE=[0, 0, 0], AngEuler=[0, 0, 0], VelE=[0, 0, 0], PWMs=[0] * 8, runnedTime=-1, windowID=-1)`¶

`sendUE4PosScale100(copterID, vehicleType, PosE, AngEuler, MotorRPMSMean, Scale, isFitGround=False, windowID=-1)`¶

`sendUE4PosScalePwm20(copterID, vehicleType, PosE, AngEuler, Scale, PWMs, isFitGround=False, windowID=-1)`¶

`getUE4Pos(CopterID=1)`¶

`getUE4Data(CopterID=1)`¶

`initUE4MsgRec()`¶