MJCF Importer Extension [isaacsim.asset.importer.mjcf]#

MJCF Import Commands#

The following commands can be used to simplify the import process. Below is a sample demonstrating how to import the Ant MJCF included with this extension

 1import omni.kit.commands
 2from pxr import UsdLux, Sdf, Gf, UsdPhysics, PhysicsSchemaTools
 3
 4# setting up import configuration:
 5status, import_config = omni.kit.commands.execute("MJCFCreateImportConfig")
 6import_config.set_fix_base(True)
 7import_config.set_import_inertia_tensor(True)
 8
 9# Get path to extension data:
10ext_manager = omni.kit.app.get_app().get_extension_manager()
11ext_id = ext_manager.get_enabled_extension_id("isaacsim.asset.importer.mjcf")
12extension_path = ext_manager.get_extension_path(ext_id)
13
14# import MJCF
15omni.kit.commands.execute(
16    "MJCFCreateAsset",
17    mjcf_path=extension_path + "/data/mjcf/nv_ant.xml",
18    import_config=import_config,
19    prim_path="/ant"
20)
21
22# get stage handle
23stage = omni.usd.get_context().get_stage()
24
25# enable physics
26scene = UsdPhysics.Scene.Define(stage, Sdf.Path("/physicsScene"))
27# set gravity
28scene.CreateGravityDirectionAttr().Set(Gf.Vec3f(0.0, 0.0, -1.0))
29scene.CreateGravityMagnitudeAttr().Set(9.81)
30
31# add lighting
32distantLight = UsdLux.DistantLight.Define(stage, Sdf.Path("/DistantLight"))
33distantLight.CreateIntensityAttr(500)
class MJCFCreateAsset(*args: Any, **kwargs: Any)#

This command parses and imports a given mjcf file.

Parameters:

  • arg0 (str) – The absolute path the mjcf file

  • arg1 (isaacsim.asset.importer.mjcf._mjcf.ImportConfig) – Import configuration

  • arg2 (str) – Path to the robot on the USD stage

  • arg3 (str) – destination path for robot usd. Default is “” which will load the robot in-memory on the open stage.

class MJCFCreateImportConfig(*args: Any, **kwargs: Any)#

Returns an ImportConfig object that can be used while parsing and importing. Should be used with the MJCFCreateAsset command

Returns:

Parsed MJCF stored in an internal structure.

Return type:

isaacsim.asset.importer.mjcf._mjcf.ImportConfig

This extension provides an interface to the MJCF importer.

Example

Setup the configuration parameters before importing. Files must be parsed before imported.

>>> import omni
>>> import os
>>> from isaacsim.asset.importer.mjcf import _mjcf
>>> mjcf_interface = _mjcf.acquire_mjcf_interface()
>>>
>>> # setup config params
>>> import_config = _mjcf.ImportConfig()
>>> import_config.fix_base = True
>>>
>>> # parse and import file

>>> ext_manager = omni.kit.app.get_app().get_extension_manager()
>>> ext_id = ext_manager.get_enabled_extension_id("isaacsim.asset.importer.mjcf")
>>> extension_path = ext_manager.get_extension_path(ext_id)
>>> mjcf_path = os.path.abspath(extension_path + "/data/mjcf/nv_ant.xml")
>>> mjcf_interface.create_asset_mjcf(mjcf_path, "", import_config)

Refer to the sample documentation for more examples and usage

class Mjcf#
create_asset_mjcf(
self: isaacsim.asset.importer.mjcf._mjcf.Mjcf,
fileName: str,
primName: str,
config: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
stage_identifier: str = '',
) → None#

Parse and import MJCF file.

Parameters:

  • arg0 (str) – The absolute path to the mjcf

  • arg1 (str) – Path to the robot on the USD stage

  • arg2 (isaacsim.asset.importer.mjcf._mjcf.ImportConfig) – Import configuration

  • arg3 (str) – optional: path to stage to use for importing. leaving it empty will import on open stage. If the open stage is a new stage, textures will not load.

class ImportConfig#
set_convex_decomp(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: bool,
) → None#
set_create_body_for_fixed_joint(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: bool,
) → None#
set_create_physics_scene(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: bool,
) → None#
set_default_drive_strength(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: float,
) → None#
set_density(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: float,
) → None#
set_distance_scale(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: float,
) → None#
set_fix_base(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: bool,
) → None#
set_import_inertia_tensor(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: bool,
) → None#
set_import_sites(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: bool,
) → None#
set_instanceable_usd_path(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: str,
) → None#
set_make_default_prim(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: bool,
) → None#
set_make_instanceable(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: bool,
) → None#
set_merge_fixed_joints(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: bool,
) → None#
set_override_com(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: bool,
) → None#
set_override_inertia(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: bool,
) → None#
set_self_collision(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: bool,
) → None#
set_visualize_collision_geoms(
self: isaacsim.asset.importer.mjcf._mjcf.ImportConfig,
arg0: bool,
) → None#
property convex_decomp#

Decompose a convex mesh into smaller pieces for a closer fit

property create_body_for_fixed_joint#

creates body for fixed joint

property create_physics_scene#

add a physics scene to the stage on import

property default_drive_strength#

default drive stiffness used for joints

property density#

default density used for links

property distance_scale#

Set the unit scaling factor, 1.0 means meters, 100.0 means cm

property fix_base#

Create fix joint for base link

property import_inertia_tensor#

Import inertia tensor from mjcf, if not specified in mjcf it will import as identity

property instanceable_usd_path#

USD file to store instanceable mehses in

property make_default_prim#

set imported robot as default prim

property make_instanceable#

Creates an instanceable version of the asset. All meshes will be placed in a separate USD file

property merge_fixed_joints#

Consolidating links that are connected by fixed joints

property override_com#

whether to compute the center of mass from geometry and override values given in the original asset

property override_inertia_tensor#

Whether to compute the inertia tensor from geometry and override values given in the original asset

property self_collision#

Self collisions between links in the articulation