Scenery asset (automatically registered as “mars_surface” scenery/terrain)

class MarsSurface(Terrain):
    ## Scenario - The asset is suitable for the Mars domain
    DOMAINS: ClassVar[Sequence[Domain]] = (Domain.MARS,)

    ## Source selector — opt in to real DEMs by passing `source="real"`.
    source: Literal["procedural", "real"] = "procedural"
    site: str = "jezero"

    ## Model - filled in model_post_init
    asset_cfg: AssetBaseCfg | None = None  # type: ignore[assignment]

    def _build_procedural_asset_cfg(self) -> AssetBaseCfg:
        return AssetBaseCfg(
            prim_path="{ENV_REGEX_NS}/mars_surface",
            ## Spawner procedurally generates SimForge models
            spawn=SimforgeAssetCfg(
                assets=[simforge_foundry.MarsSurface()],
                collision_props=CollisionPropertiesCfg(),
                # Static triangle-mesh collision is required; otherwise
                # particles and objects fall through the SimForge mesh.
                mesh_collision_props=MeshCollisionPropertiesCfg(
                    mesh_approximation="none"
                ),
            ),
        )

    def model_post_init(self, __context):
        # Build first so the parent forwards density, scale, and texture
        # settings to the newly constructed spawner config.
        self.asset_cfg = resolve_surface_asset_cfg(
            surface_name=self.__class__.__name__,
            body="mars",
            site=self.site,
            source=self.source,
            build_procedural_asset_cfg=self._build_procedural_asset_cfg,
            build_real_asset_cfg=build_real_terrain_asset_cfg,
        )
        super().model_post_init(__context)

Object asset (automatically registered as “sample_tube” object/common)

class SampleTube(Object):
    ## Model - Rigid object affected by physics
    asset_cfg: RigidObjectCfg = RigidObjectCfg(
        prim_path="{ENV_REGEX_NS}/sample",
        ## Spawner loads a static USD file
        spawn=UsdFileCfg(
            usd_path=(
                SRB_ASSETS_DIR_SRB_OBJECT.joinpath("sample_tube.usdc").as_posix()
            ),
            collision_props=CollisionPropertiesCfg(),
            mesh_collision_props=MeshCollisionPropertiesCfg(
                mesh_approximation="convexDecomposition"
            ),
            rigid_props=RigidBodyPropertiesCfg(),
            mass_props=MassPropertiesCfg(density=1500.0),
        ),
    )

Robot asset (automatically registered as “franka” robot/manipulator)

class Franka(SerialManipulator):
    ## Model - Articulation with several links connected by joints
    asset_cfg: ArticulationCfg = ArticulationCfg(
        prim_path="{ENV_REGEX_NS}/franka",
        ## Spawner loads a static USD file
        spawn=UsdFileCfg(
            usd_path=SRB_ASSETS_DIR_SRB_ROBOT.joinpath("manipulator")
            .joinpath("franka_arm.usdz")
            .as_posix(),
            ...
        ),
        ## Initial joint configuration of the robot
        init_state=ArticulationCfg.InitialStateCfg(
            joint_pos={
                "panda_joint1": 0.0,
                "panda_joint2": 0.0,
                "panda_joint3": 0.0,
                "panda_joint4": radians(-90.0),
                "panda_joint5": 0.0,
                "panda_joint6": radians(90.0),
                "panda_joint7": radians(45.0),
            },
        ),
        ...
    )
    ## End effector - The default hand is separate to allow for easy replacement
    end_effector: Tool | None = FrankaHand()

    ## Action modes — coded-in alternatives selectable via
    ## `env.robot.action_mode=<key>`. The first entry is the default.
    action_modes: ClassVar[dict[str, ActionGroup]] = {
        "diff_ik": InverseKinematicsActionGroup(
            DifferentialInverseKinematicsActionCfg(
                asset_name="robot",
                joint_names=["panda_joint[1-7]"],
                base_name="panda_link0",
                body_name="panda_link7",
                controller=DifferentialIKControllerCfg(
                    command_type="pose",
                    use_relative_mode=True,
                    ik_method="dls",
                ),
                scale=0.1,
                body_offset=DifferentialInverseKinematicsActionCfg.OffsetCfg(),
            ),
        ),
        "osc_fixed": OperationalSpaceControlActionGroup(
            OperationalSpaceControllerActionCfg(
                asset_name="robot",
                joint_names=["panda_joint[1-7]"],
                body_name="panda_link7",
                controller_cfg=OperationalSpaceControllerCfg(
                    target_types=["pose_rel"],
                    impedance_mode="fixed",
                    motion_stiffness_task=100.0,
                    motion_damping_ratio_task=1.0,
                    nullspace_control="position",
                    inertial_dynamics_decoupling=True,
                ),
                nullspace_joint_pos_target="center",
                position_scale=0.1,
                orientation_scale=0.1,
                body_offset=OperationalSpaceControllerActionCfg.OffsetCfg(),
            )
        ),
        "osc_var_stiffness": OperationalSpaceControlActionGroup(
            OperationalSpaceControllerActionCfg(
                asset_name="robot",
                joint_names=["panda_joint[1-7]"],
                body_name="panda_link7",
                controller_cfg=OperationalSpaceControllerCfg(
                    target_types=["pose_rel"],
                    impedance_mode="variable_kp",
                    motion_stiffness_limits_task=(10.0, 250.0),
                    motion_damping_ratio_task=1.0,
                    nullspace_control="position",
                    inertial_dynamics_decoupling=True,
                ),
                nullspace_joint_pos_target="center",
                position_scale=0.1,
                orientation_scale=0.1,
                stiffness_scale=120.0,
                body_offset=OperationalSpaceControllerActionCfg.OffsetCfg(),
            )
        ),
        "osc_var_full": OperationalSpaceControlActionGroup(
            OperationalSpaceControllerActionCfg(
                asset_name="robot",
                joint_names=["panda_joint[1-7]"],
                body_name="panda_link7",
                controller_cfg=OperationalSpaceControllerCfg(
                    target_types=["pose_rel"],
                    impedance_mode="variable",
                    motion_stiffness_limits_task=(10.0, 250.0),
                    motion_damping_ratio_limits_task=(0.5, 2.5),
                    nullspace_control="position",
                    inertial_dynamics_decoupling=True,
                ),
                nullspace_joint_pos_target="center",
                position_scale=0.1,
                orientation_scale=0.1,
                stiffness_scale=120.0,
                damping_ratio_scale=1.0,
                body_offset=OperationalSpaceControllerActionCfg.OffsetCfg(),
            )
        ),
        "joint_pos_rel": JointPositionRelativeActionGroup(),
    }
    ...
    ## Frames - Relevant frames for attaching the robot and mounting tool/sensors
    frame_base: Frame = Frame(prim_relpath="panda_link0")
    frame_flange: Frame = Frame(
        prim_relpath="panda_link7",
        offset=Transform(
            pos=(0.0, 0.0, 0.107),
            rot=rpy_to_quat(0.0, 0.0, -45.0),
        ),
    )