ROS2 Simulation Control#

Note

Simulation Control is only available on Linux at this time.

Learning Objectives#

In this page, you will learn how to:

  • Understand the ROS 2 Simulation Control extension for Isaac Sim

  • Control Isaac Sim simulations using ROS 2 services and actions

  • Manipulate simulation entities using ROS 2 interfaces

  • Step through simulations programmatically

Getting Started#

Important

Make sure to source ROS 2 appropriately from the terminal before running Isaac Sim.

Prerequisite

  • Complete ROS 2 Installation.

  • If using multiple systems, set the FASTRTPS_DEFAULT_PROFILES_FILE environment variable as per instructions in ROS 2 Installation before launching Isaac Sim, as well as any terminal where ROS messages will be sent or received, and ROS2 Extension is enabled.

  • Download and build the Simulation Interfaces package in a ROS 2 workspace.

Overview#

The ROS 2 Simulation Control extension allows you to control Isaac Sim programmatically or through the ROS 2 command line interface using the Simulation Interfaces package to enable workflows like automated testing. This page lists and provides example commands for all of the services and actions from Simulation Interfaces supported by Isaac Sim.

Enabling the Extension#

  1. Open Isaac Sim

  2. Enable the extension from the Extension Manager: isaacsim.ros2.sim_control

Available Services and Actions#

The extension provides the following ROS 2 services:

  • isaacsim/GetSimulatorFeatures: Lists the supported features in this Isaac Sim implementation

  • isaacsim/SetSimulationState: Set simulation to specific state (playing/paused/stopped)

  • isaacsim/GetSimulationState: Get current simulation state

  • isaacsim/GetEntities: Get list of all entities (prims) in the simulation

  • isaacsim/GetEntityInfo: Get detailed information about a specific entity

  • isaacsim/GetEntityState: Get the world pose, twist, and acceleration of a specific entity

  • isaacsim/GetEntitiesStates: Get world states of multiple entities with filtering

  • isaacsim/DeleteEntity: Delete a specific entity (prim) from the simulation

  • isaacsim/SpawnEntity: Spawn a new entity into the simulation at a specified location

  • isaacsim/ResetSimulation: Reset the simulation environment to its initial state

  • isaacsim/SetEntityState: Sets the state (pose, twist) of a specific entity in the simulation

  • isaacsim/StepSimulation: Step the simulation forward by a specific number of frames

And the following ROS 2 actions:

  • isaacsim/SimulateSteps: Action for stepping the simulation with progress feedback

Using the ROS 2 Simulation Control Services#

This section describes how to use each of the available services in detail.

GetSimulatorFeatures Service#

The GetSimulatorFeatures service lists the subset of services and actions supported by Isaac Sim from simulation_interfaces.

ros2 service call /isaacsim/GetSimulatorFeatures simulation_interfaces/srv/GetSimulatorFeatures

Notes:

  • Returns a list of supported features (e.g., SPAWNING, DELETING, ENTITY_STATE_GETTING)

  • Reports USD file format support via the spawn_formats field

  • Provides custom_info with details about the implementation

  • See the full list of simulator features

SetSimulationState Service#

The SetSimulationState service updates the global state of the simulation (stopped/playing/paused/quitting) corresponding to enums defined in SimulationState.msg (STATE_STOPPED, STATE_PLAYING, STATE_PAUSED, STATE_QUITTING).

  1. To set simulation state to playing:

    ros2 service call /isaacsim/SetSimulationState simulation_interfaces/srv/SetSimulationState "{state: {state: 1}}"  # 1=playing

  2. To set simulation state to paused:

    ros2 service call /isaacsim/SetSimulationState simulation_interfaces/srv/SetSimulationState "{state: {state: 2}}"  # 2=paused

  3. To set simulation state to stopped:

    ros2 service call /isaacsim/SetSimulationState simulation_interfaces/srv/SetSimulationState "{state: {state: 0}}"  # 0=stopped

  4. To quit the simulator:

    ros2 service call /isaacsim/SetSimulationState simulation_interfaces/srv/SetSimulationState "{state: {state: 3}}"  # 3=quit

Notes:

  • State 0 (Stopped) is equivalent to pausing and resetting the simulation

  • State 1 (Playing) starts the simulation timeline

  • State 2 (Paused) pauses the simulation at the current time

  • State 3 (Quitting) shuts down Isaac Sim

GetSimulationState Service#

The GetSimulationState service retrieves the current state of the entire simulation (stopped/playing/paused/quitting).

ros2 service call /isaacsim/GetSimulationState simulation_interfaces/srv/GetSimulationState

Notes:

  • Returns state 0 for stopped, 1 for playing, 2 for paused

  • Used to query the simulation state before performing operations like stepping

GetEntities Service#

The GetEntities service retrieves a list of all entities present in the simulation with optional filtering (using regex pattern).

  1. Get all entities in the simulation:

    ros2 service call /isaacsim/GetEntities simulation_interfaces/srv/GetEntities "{filters: {filter: ''}}"

  2. Get entities with full paths or partial paths. In this case filter for prims containing ‘camera’ in the path:

    ros2 service call /isaacsim/GetEntities simulation_interfaces/srv/GetEntities "{filters: {filter: 'camera'}}"

  3. Get entities with paths starting with ‘/World’:

    ros2 service call /isaacsim/GetEntities simulation_interfaces/srv/GetEntities "{filters: {filter: '^/World'}}"

  4. Get entities with paths ending with ‘mesh’:

    ros2 service call /isaacsim/GetEntities simulation_interfaces/srv/GetEntities "{filters: {filter: 'mesh$'}}"

Notes:

  • The filter parameter accepts POSIX Extended regular expressions for matching entity names (prim paths)

  • Isaac Sim uses the full USD prim paths as entity names

GetEntityInfo Service#

The GetEntityInfo service provides detailed information about a specific entity, such as its type and properties.

ros2 service call /isaacsim/GetEntityInfo simulation_interfaces/srv/GetEntityInfo "{entity: '/World/robot'}"

Notes:

  • Returns RESULT_OK with EntityInfo if the entity exists

  • Returns RESULT_OPERATION_FAILED if the entity doesn’t exist

  • The EntityInfo contains: * category: Currently always set to OBJECT (EntityCategory.OBJECT) * description: Empty string (reserved for future use) * tags: Empty array (reserved for future use)

GetEntityState Service#

The GetEntityState service gets the pose, twist, acceleration of a specific entity relative to a given reference frame. Only world frame is supported currently.

ros2 service call /isaacsim/GetEntityState simulation_interfaces/srv/GetEntityState "{entity: '/World/robot'}"

Notes:

  • For entities with RigidBodyAPI, both pose and velocities will be returned

  • For entities without RigidBodyAPI, only pose will be returned with zero velocities

  • Acceleration values are always reported as zero (not provided by the current API)

  • Returns RESULT_OK if successfully retrieved entity state

  • Returns RESULT_NOT_FOUND if entity does not exist

  • Returns RESULT_OPERATION_FAILED if error retrieving entity state

GetEntitiesStates Service#

The GetEntitiesStates service fetches the states (pose, twist, acceleration) in the world frame of multiple entities in the simulation.

  1. Get states for all entities in the simulation:

    ros2 service call /isaacsim/GetEntitiesStates simulation_interfaces/srv/GetEntitiesStates "{filters: {filter: ''}}"

  2. Get states for entities containing ‘robot’ in their path:

    ros2 service call /isaacsim/GetEntitiesStates simulation_interfaces/srv/GetEntitiesStates "{filters: {filter: 'robot'}}"

  3. Get states for entities with paths starting with ‘/World’:

    ros2 service call /isaacsim/GetEntitiesStates simulation_interfaces/srv/GetEntitiesStates "{filters: {filter: '^/World'}}"

Notes:

  • Combines functionality from GetEntities and GetEntityState services

  • Filters entities first using regex pattern matching

  • Retrieves state for each filtered entity

  • Returns list of entity paths and corresponding states

  • For entities with RigidBodyAPI, both pose and velocities will be returned

  • For entities without RigidBodyAPI, only pose will be returned with zero velocities

  • Acceleration values are always reported as zero (not provided by the current API)

  • Using this service is more efficient than making multiple GetEntityState calls when you need states for many entities

  • Returns RESULT_OK if successfully retrieved entity states

  • Returns RESULT_OPERATION_FAILED if error in filtering or retrieving states

DeleteEntity Service#

The DeleteEntity service deletes a specified entity in the simulation.

ros2 service call /isaacsim/DeleteEntity simulation_interfaces/srv/DeleteEntity "{entity: '/World/robot'}"

Notes:

  • The service will return RESULT_OK if the entity was successfully deleted

  • Returns RESULT_OPERATION_FAILED if the entity is protected and cannot be deleted

  • Uses prim_utils.is_prim_no_delete() to check if a prim can be deleted before attempting deletion

SpawnEntity Service#

The SpawnEntity service spawns a new entity into the simulation at a specified location.

  1. Basic entity spawn with default position:

    ros2 service call /isaacsim/SpawnEntity simulation_interfaces/srv/SpawnEntity "{name: 'MyEntity', allow_renaming: false, uri: '/path/to/model.usd'}"

  2. Spawn with specific position and orientation:

    ros2 service call /isaacsim/SpawnEntity simulation_interfaces/srv/SpawnEntity "{name: 'PositionedEntity', allow_renaming: false, uri: '/path/to/model.usd', initial_pose: {pose: {position: {x: 1.0, y: 2.0, z: 3.0}, orientation: {w: 1.0, x: 0.0, y: 0.0, z: 0.0}}}}"

  3. Empty Xform creation (no URI):

    ros2 service call /isaacsim/SpawnEntity simulation_interfaces/srv/SpawnEntity "{name: 'EmptyXform', allow_renaming: false, uri: ''}"

  4. With auto-renaming enabled:

    ros2 service call /isaacsim/SpawnEntity simulation_interfaces/srv/SpawnEntity "{name: 'AutoRenamedEntity', allow_renaming: true, uri: '/path/to/model.usd'}"

  5. With namespace specified:

    ros2 service call /isaacsim/SpawnEntity simulation_interfaces/srv/SpawnEntity "{name: 'NamespacedEntity', allow_renaming: false, uri: '/path/to/model.usd', entity_namespace: 'robot1'}"

Notes:

  • If URI is provided, loads the USD file as a reference in the given prim path

  • If URI is not provided, creates a Xform at the given prim path

  • All spawned prims are marked with a simulationInterfacesSpawned attribute for tracking

  • Returns RESULT_OK if the entity was successfully spawned

  • Returns NAME_NOT_UNIQUE (101) if the entity name already exists and allow_renaming is false

  • Returns NAME_INVALID (102) if the entity name is empty and allow_renaming is false

  • Returns RESOURCE_PARSE_ERROR (106) if failed to parse or load USD file

ResetSimulation Service#

The ResetSimulation service resets the simulation environment to its initial state.

ros2 service call /isaacsim/ResetSimulation simulation_interfaces/srv/ResetSimulation

Notes:

  • Stops the simulation timeline

  • Finds and removes all prims with simulationInterfacesSpawned attribute

  • Uses multiple passes to ensure all spawned entities are removed

  • Restarts the simulation timeline

  • Returns RESULT_OK if successfully reset

  • Returns RESULT_OPERATION_FAILED if error resetting simulation

SetEntityState Service#

The SetEntityState service sets the state (pose, twist) of a specific entity in the simulation. Only transforms in the world frame are currently accepted.

  1. Set only position and orientation:

    ros2 service call /isaacsim/SetEntityState simulation_interfaces/srv/SetEntityState "{
  entity: '/World/Cube',
  state: {
    header: {frame_id: 'world'},
    pose: {
      position: {x: 1.0, y: 2.0, z: 3.0},
      orientation: {w: 1.0, x: 0.0, y: 0.0, z: 0.0}
    },
    twist: {
      linear: {x: 0.0, y: 0.0, z: 0.0},
      angular: {x: 0.0, y: 0.0, z: 0.0}
    }
  }
}"

  2. Set position, orientation and velocity (for entities with rigid body physics):

    ros2 service call /isaacsim/SetEntityState simulation_interfaces/srv/SetEntityState "{
  entity: '/World/RigidBody',
  state: {
    header: {frame_id: 'world'},
    pose: {
      position: {x: 1.0, y: 2.0, z: 3.0},
      orientation: {w: 1.0, x: 0.0, y: 0.0, z: 0.0}
    },
    twist: {
      linear: {x: 0.5, y: 0.0, z: 0.0},
      angular: {x: 0.0, y: 0.0, z: 0.1}
    }
  }
}"

Notes:

  • The position and orientation are always updated for any entity

  • Velocities are only set for entities with a RigidBodyAPI

  • For non-rigid bodies, only position and orientation will be set (velocity settings are ignored)

  • Acceleration settings are not currently supported and will be ignored

  • Returns RESULT_OK if successfully set entity state

  • Returns RESULT_NOT_FOUND if entity does not exist

  • Returns RESULT_OPERATION_FAILED if error setting entity state

StepSimulation Service#

The StepSimulation service simulates a finite number of steps and returns to PAUSED state.

  1. Step the simulation by 1 frame (note: will use 2 steps internally):

    ros2 service call /isaacsim/StepSimulation simulation_interfaces/srv/StepSimulation "{steps: 1}"

  2. Step the simulation by 10 frames:

    ros2 service call /isaacsim/StepSimulation simulation_interfaces/srv/StepSimulation "{steps: 10}"

  3. Step the simulation by 100 frames:

    ros2 service call /isaacsim/StepSimulation simulation_interfaces/srv/StepSimulation "{steps: 100}"

Notes:

  • The simulation must be in a paused state before stepping can be performed

  • The service call will block until all steps are completed

  • After stepping completes, the simulation will automatically return to a paused state

  • Important limitation: When steps=1 is requested, the service will automatically use steps=2 instead. Only step values greater than 1 are available. The minimum effective step count is 2.

  • Returns RESULT_OK if stepping completed successfully

  • Returns RESULT_INCORRECT_STATE if the simulation is not paused when the service is called

  • Returns RESULT_OPERATION_FAILED if any error occurs during stepping

Using the ROS 2 Simulation Control Actions#

SimulateSteps Action#

The SimulateSteps action simulates a finite number of steps and returns to PAUSED state with feedback after each step.

  1. Basic usage - Step the simulation by 10 frames:

    ros2 action send_goal /isaacsim/SimulateSteps simulation_interfaces/action/SimulateSteps "{steps: 10}"

  2. With feedback - Step the simulation by 20 frames and show feedback:

    ros2 action send_goal /isaacsim/SimulateSteps simulation_interfaces/action/SimulateSteps "{steps: 20}" --feedback

Notes:

  • The simulation must be in a paused state before stepping can be performed

  • After steps are completed, the simulation will return to a paused state

  • You will receive feedback after each step showing completed and remaining steps

  • The action can be canceled while executing

  • Important limitation: When steps=1 is requested, the action will automatically use steps=2 instead. Only step values greater than 1 are available. The minimum effective step count is 2.

Technical Details#

The extension uses the omni.timeline interface to control the simulation state and provides a clean ROS 2 interface through standard services. The implementation includes:

  • A singleton ROS2ServiceManager to handle all ROS 2 services through a single node

  • A SimulationControl class that interfaces with Isaac Sim’s timeline

  • Thread-safe implementation for ROS 2 spinning independent of Action Graph interface

Summary#

This page covered:

  • The ROS 2 Simulation Control extension and its capabilities

  • How to enable the extension in Isaac Sim

  • Using ROS 2 services to control simulation state (play, pause, stop)

  • Manipulating entities in the simulation (spawn, delete, get state, set state)

  • Stepping through the simulation programmatically

  • Technical implementation details of the extension