lerobot/openarm-usd

OpenArm USD

An OpenUSD model of the bimanual OpenArm whose joints and links carry the names of LeRobot's openarm_bimanual URDF, so the joint values of OpenArm LeRobot datasets drive it the way they drive the URDF.

Root USD	openarm_bimanual/simready_usd/openarm_bimanual.usd: one layer, 6 MB
Units	meters, Z up; joint limits in degrees
Joints, per arm (left, right)	openarm_<side>_joint1 to joint7 (revolute), openarm_<side>_finger_joint1 and finger_joint2 (prismatic, the second following the first), <side>_openarm_hand_joint (fixed)
Links	openarm_body_link0; per arm openarm_<side>_link0 to link7, openarm_<side>_hand, openarm_<side>_left_finger, openarm_<side>_right_finger, and the openarm_<side>_hand_tcp tip frame
Geometry	58 meshes, 404k triangles, UsdPreviewSurface materials

Checked against the URDF

• Every link and moving joint of openarm_bimanual_web.urdf is here, under the same name, except its empty world root. The link0s and tool points, fixed there, are plain frames here.
• Posed at 200 random joint configurations, every link lands within 0.001 mm and 0.001° of the URDF's: same zero pose, axes and directions. The URDF takes radians, this model degrees. The finger bodies' frames sit 1 mm from the URDF's at every pose, which leaves their motion unchanged.
• It loads in @huggingface/usd-web-viewer with no warnings.

Usage

import { loadUsd } from "@huggingface/usd-web-viewer";

const { root } = await loadUsd(
  "https://huggingface.co/datasets/lerobot/openarm-usd/resolve/main/openarm_bimanual/simready_usd/openarm_bimanual.usd",
);
scene.add(root); // a THREE.Group, Y up

Source and changes

Built from NVIDIA's openarm_bimanual asset for Isaac Sim 6.0 (Apache-2.0), also in enactic/openarm_isaac_lab. Changes:

• composed into one layer, without the sensors, render settings and colliders;
• the ee_tcp bodies, 13 mm from the URDF's tool point, replaced by hand_tcp frames where the URDF puts them;
• the link7-to-hand joints made fixed, and they and the body link renamed to the URDF's;
• OmniPBR materials converted to UsdPreviewSurface;
• visual meshes decimated from 2.2M to 404k triangles, within 3.5 mm of the original.

Without colliders it is meant for display; for simulation, use NVIDIA's original. scripts/build_openarm.py rebuilds it (needs usd-core, numpy and fast-simplification). The package follows the SimReady packaging layout, with its file list and hashes; it has not been through NVIDIA's SimReady validation.