Implementation:CARLA simulator Carla Python Commands Bindings

Knowledge Sources	CARLA
Domains	Python Bindings, Batch Commands
Last Updated	2026-02-15 05:00 GMT

Overview

Boost.Python binding file that exposes CARLA's batch command system to the Python API, enabling efficient bulk operations on actors.

Description

This file defines the export_commands() function that registers batch command classes within the libcarla.command submodule. It exposes SpawnActor (with chaining via then()), DestroyActor, ApplyVehicleControl, ApplyVehicleAckermannControl, ApplyWalkerControl, ApplyVehiclePhysicsControl, ApplyTransform, ApplyWalkerState, ApplyTargetVelocity, ApplyTargetAngularVelocity, ApplyImpulse, ApplyForce, ApplyAngularImpulse, ApplyTorque, SetSimulatePhysics, SetEnableGravity, SetAutopilot, ShowDebugTelemetry, and SetVehicleLightState. The Response class provides actor_id, error, and has_error() for checking batch results. A FutureActor sentinel value (0) is provided for referencing not-yet-spawned actors in chained commands. All command types are implicitly convertible to the base Command type.

Usage

These command classes are used with client.apply_batch() and client.apply_batch_sync() to perform multiple actor operations in a single server call, significantly reducing overhead when spawning or controlling many actors.

Code Reference

Source Location

• Repository: CARLA
• File: PythonAPI/carla/src/Commands.cpp

Signature

void export_commands();

// Key classes in libcarla.command submodule:
class_<cr::Command::SpawnActor>("SpawnActor")
class_<cr::Command::DestroyActor>("DestroyActor")
class_<cr::Command::ApplyVehicleControl>("ApplyVehicleControl")
class_<cr::Command::ApplyTransform>("ApplyTransform")
class_<cr::Command::SetAutopilot>("SetAutopilot")
class_<cr::CommandResponse>("Response", no_init)

Import

import carla
SpawnActor = carla.command.SpawnActor
DestroyActor = carla.command.DestroyActor

I/O Contract

Inputs

Name	Type	Required	Description
blueprint	carla.ActorBlueprint	Yes (SpawnActor)	Blueprint for actor to spawn
transform	carla.Transform	Yes (SpawnActor)	Spawn location and rotation
actor / actor_id	carla.Actor / int	Yes (most commands)	Target actor or actor ID
control	carla.VehicleControl	Yes (ApplyVehicleControl)	Control to apply
enabled	bool	Yes (SetAutopilot)	Whether to enable autopilot

Outputs

Name	Type	Description
response.actor_id	int	ID of spawned/affected actor (0 on error)
response.error	str	Error message if operation failed
response.has_error()	bool	Whether the command encountered an error

Usage Examples

import carla

client = carla.Client('localhost', 2000)
world = client.get_world()

SpawnActor = carla.command.SpawnActor
SetAutopilot = carla.command.SetAutopilot
FutureActor = carla.command.FutureActor

bp = world.get_blueprint_library().find('vehicle.tesla.model3')
transforms = world.get_map().get_spawn_points()[:10]

# Batch spawn with autopilot chaining
batch = []
for t in transforms:
    batch.append(SpawnActor(bp, t).then(SetAutopilot(FutureActor, True)))

results = client.apply_batch_sync(batch, True)
for result in results:
    if not result.has_error():
        print(f"Spawned actor {result.actor_id}")

Related Pages

• Environment:CARLA_simulator_Carla_Python_API_Runtime