Implementation:CARLA simulator Carla Transform Constructor

Knowledge Sources	CARLA Simulator CARLA Documentation
Domains	Simulation, Perception
Last Updated	2026-02-15 00:00 GMT

Overview

Concrete tool for defining 3D sensor mounting positions and orientations relative to a vehicle provided by the CARLA simulator.

Description

carla.Transform combines a carla.Location (x, y, z in meters) and a carla.Rotation (pitch, yaw, roll in degrees) to define a 6-DOF pose in 3D space. When used with World.spawn_actor() and the attach_to parameter, the transform specifies the sensor's mounting position and orientation relative to the parent vehicle's local coordinate frame. The Location constructor takes positional arguments (x, y, z) and the Rotation constructor takes (pitch, yaw, roll), all as floating-point values.

Usage

A Transform is created for each sensor being spawned and passed as the second argument to World.spawn_actor(). Each sensor in a data collection rig requires its own transform defining where it sits on the vehicle and which direction it faces.

Code Reference

Source Location

• Repository: CARLA
• File: LibCarla/source/carla/geom/Transform.h, PythonAPI/carla/src/Geometry.cpp
• Lines: Transform.h (full file), Geometry.cpp (full file)

Signature

carla.Location(x: float = 0.0, y: float = 0.0, z: float = 0.0)
carla.Rotation(pitch: float = 0.0, yaw: float = 0.0, roll: float = 0.0)
carla.Transform(location: carla.Location, rotation: carla.Rotation)

Import

import carla

I/O Contract

Inputs

Name	Type	Required	Description
x	float	No	Forward offset in meters from the vehicle reference frame origin. Positive = forward. Default 0.0.
y	float	No	Lateral offset in meters. Positive = right. Default 0.0.
z	float	No	Vertical offset in meters. Positive = up. Default 0.0.
pitch	float	No	Rotation around the y-axis in degrees. Positive = nose up. Default 0.0.
yaw	float	No	Rotation around the z-axis in degrees. Positive = clockwise from above. Default 0.0.
roll	float	No	Rotation around the x-axis in degrees. Positive = right side down. Default 0.0.

Outputs

Name	Type	Description
location	carla.Location	3D position vector with x, y, z attributes.
rotation	carla.Rotation	3D orientation with pitch, yaw, roll attributes.
transform	carla.Transform	Combined 6-DOF pose object. Provides get_forward_vector(), get_right_vector(), get_up_vector(), and get_matrix() for accessing the underlying transformation.

Usage Examples

Basic Example

import carla

# Define a forward-facing camera on the vehicle roof
camera_transform = carla.Transform(
    carla.Location(x=1.5, y=0.0, z=2.4),   # 1.5m forward, 2.4m above origin
    carla.Rotation(pitch=0.0, yaw=0.0, roll=0.0)  # looking straight ahead
)

# Define a roof-mounted LiDAR
lidar_transform = carla.Transform(
    carla.Location(x=0.0, y=0.0, z=2.5),   # centered, 2.5m above origin
    carla.Rotation(pitch=0.0, yaw=0.0, roll=0.0)
)

Full Sensor Suite Placement

import carla

# --- Forward-facing RGB camera (dashboard mount) ---
front_cam_tf = carla.Transform(
    carla.Location(x=1.5, y=0.0, z=2.4),
    carla.Rotation(pitch=-5.0, yaw=0.0, roll=0.0)  # slight downward tilt
)

# --- Left-facing camera (side mirror position) ---
left_cam_tf = carla.Transform(
    carla.Location(x=0.5, y=-0.9, z=1.8),
    carla.Rotation(pitch=0.0, yaw=-90.0, roll=0.0)  # facing left
)

# --- Right-facing camera (side mirror position) ---
right_cam_tf = carla.Transform(
    carla.Location(x=0.5, y=0.9, z=1.8),
    carla.Rotation(pitch=0.0, yaw=90.0, roll=0.0)   # facing right
)

# --- Rear-facing camera ---
rear_cam_tf = carla.Transform(
    carla.Location(x=-2.0, y=0.0, z=2.0),
    carla.Rotation(pitch=0.0, yaw=180.0, roll=0.0)  # facing backward
)

# --- Roof-mounted LiDAR (centered, elevated) ---
lidar_tf = carla.Transform(
    carla.Location(x=0.0, y=0.0, z=2.5),
    carla.Rotation(pitch=0.0, yaw=0.0, roll=0.0)
)

# --- Front radar (behind bumper) ---
radar_tf = carla.Transform(
    carla.Location(x=2.5, y=0.0, z=0.7),
    carla.Rotation(pitch=5.0, yaw=0.0, roll=0.0)    # slight upward tilt
)

# --- GNSS at center of gravity ---
gnss_tf = carla.Transform(
    carla.Location(x=0.0, y=0.0, z=0.0),
    carla.Rotation(pitch=0.0, yaw=0.0, roll=0.0)
)

# --- IMU at center of gravity ---
imu_tf = carla.Transform(
    carla.Location(x=0.0, y=0.0, z=0.0),
    carla.Rotation(pitch=0.0, yaw=0.0, roll=0.0)
)

# Spawn sensors attached to the ego vehicle
ego_vehicle = world.get_actors().filter('vehicle.*')[0]

front_cam = world.spawn_actor(rgb_bp, front_cam_tf, attach_to=ego_vehicle)
left_cam = world.spawn_actor(rgb_bp, left_cam_tf, attach_to=ego_vehicle)
right_cam = world.spawn_actor(rgb_bp, right_cam_tf, attach_to=ego_vehicle)
rear_cam = world.spawn_actor(rgb_bp, rear_cam_tf, attach_to=ego_vehicle)
lidar = world.spawn_actor(lidar_bp, lidar_tf, attach_to=ego_vehicle)
radar = world.spawn_actor(radar_bp, radar_tf, attach_to=ego_vehicle)
gnss = world.spawn_actor(gnss_bp, gnss_tf, attach_to=ego_vehicle)
imu = world.spawn_actor(imu_bp, imu_tf, attach_to=ego_vehicle)

Related Pages

Implements Principle

• Principle:CARLA_simulator_Carla_Sensor_Placement_Geometry