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7.64 kB
| """OpenArm bimanual USD from NVIDIA's Isaac Sim asset, with the links and joints of | |
| openarm_bimanual_web.urdf, materials as UsdPreviewSurface and geometry decimated for the web.""" | |
| import json | |
| import sys | |
| import fast_simplification | |
| import numpy as np | |
| from pxr import Gf, Sdf, Usd, UsdGeom, UsdPhysics, UsdShade | |
| import robotusd as ru | |
| SOURCE, URDF, OUT = sys.argv[1:4] | |
| KEEP = float(sys.argv[4]) if len(sys.argv) > 4 else 0.08 # share of triangles kept | |
| SIDES = ("left", "right") | |
| layer = ru.flatten(SOURCE, {"Sensor": "None"}) | |
| stage = Usd.Stage.Open(layer) | |
| root = str(stage.GetDefaultPrim().GetPath()) | |
| # Omniverse render settings, colliders (not drawn, and most of the bytes) and the TCP bodies, | |
| # which sit 13 mm from the URDF's hand_tcp. | |
| ru.remove(layer, "/Render") | |
| for path in [p.GetPath() for p in stage.Traverse() if p.GetName() == "collisions"]: | |
| ru.remove(layer, path) | |
| for side in SIDES: | |
| ru.remove(layer, f"{root}/joints/openarm_{side}_ee_tcp_joint") | |
| ru.remove(layer, f"{root}/openarm_{side}_ee_tcp") | |
| # link7 -> hand is fixed in the URDF; NVIDIA made it a revolute with a zero range. | |
| for side in SIDES: | |
| path = f"{root}/joints/openarm_{side}_hand" | |
| spec = layer.GetPrimAtPath(path) | |
| spec.typeName = "PhysicsFixedJoint" | |
| for name in list(spec.attributes.keys()): | |
| if not name.startswith(("physics:body", "physics:localPos", "physics:localRot", "physics:jointEnabled", "physics:collisionEnabled", "physics:breakForce", "physics:breakTorque", "physics:excludeFromArticulation")): | |
| spec.RemoveProperty(spec.attributes[name]) | |
| spec.SetInfo("apiSchemas", Sdf.TokenListOp()) | |
| ru.rename(layer, path, f"{side}_openarm_hand_joint") | |
| ru.rename(layer, f"{root}/openarm_body_link", "openarm_body_link0") | |
| # The URDF's mimic finger moves over the same range as the finger it follows. | |
| for side in SIDES: | |
| joint = UsdPhysics.PrismaticJoint(stage.GetPrimAtPath(f"{root}/joints/openarm_{side}_finger_joint2")) | |
| joint.GetLowerLimitAttr().Set(0.0) | |
| joint.GetUpperLimitAttr().Set(0.044) | |
| # OmniPBR (MDL) only sets a diffuse color here: the same material as UsdPreviewSurface. | |
| for path in [p.GetPath() for p in stage.Traverse() if p.IsA(UsdShade.Material)]: | |
| p = stage.GetPrimAtPath(path) | |
| material = UsdShade.Material(p) | |
| mdl = next(c for c in p.GetChildren() if c.IsA(UsdShade.Shader)) | |
| shader = UsdShade.Shader(mdl) | |
| def value(name, default): | |
| i = shader.GetInput(name) | |
| return i.Get() if i and i.Get() is not None else default | |
| color = value("diffuse_color_constant", Gf.Vec3f(0.2, 0.2, 0.2)) | |
| roughness = value("reflection_roughness_constant", 0.5) | |
| metallic = value("metallic_constant", 0.0) | |
| ru.remove(layer, mdl.GetPath()) | |
| mspec = layer.GetPrimAtPath(p.GetPath()) | |
| for name in list(mspec.attributes.keys()): | |
| if name.startswith("outputs:"): | |
| mspec.RemoveProperty(mspec.attributes[name]) | |
| preview = UsdShade.Shader.Define(stage, p.GetPath().AppendChild("PreviewSurface")) | |
| preview.CreateIdAttr("UsdPreviewSurface") | |
| preview.CreateInput("diffuseColor", Sdf.ValueTypeNames.Color3f).Set(color) | |
| preview.CreateInput("roughness", Sdf.ValueTypeNames.Float).Set(roughness) | |
| preview.CreateInput("metallic", Sdf.ValueTypeNames.Float).Set(metallic) | |
| material.CreateSurfaceOutput().ConnectToSource(preview.ConnectableAPI(), "surface") | |
| # One mesh per material, welded, decimated, with crease-split vertex normals. | |
| before = after = 0 | |
| for path in [p.GetPath() for p in stage.Traverse() if p.IsA(UsdGeom.Mesh) and UsdGeom.Imageable(p).ComputePurpose() == "default"]: | |
| p = stage.GetPrimAtPath(path) | |
| mesh = UsdGeom.Mesh(p) | |
| points = np.array(mesh.GetPointsAttr().Get(), dtype=np.float64) | |
| counts = np.array(mesh.GetFaceVertexCountsAttr().Get()) | |
| assert (counts == 3).all(), p.GetPath() | |
| faces = np.array(mesh.GetFaceVertexIndicesAttr().Get()).reshape(-1, 3) | |
| groups = {} | |
| for subset in UsdGeom.Subset.GetAllGeomSubsets(mesh): | |
| bound = UsdShade.MaterialBindingAPI(subset.GetPrim()).ComputeBoundMaterial()[0] | |
| groups.setdefault(str(bound.GetPath()), []).append(np.array(subset.GetIndicesAttr().Get())) | |
| assigned = np.concatenate([i for v in groups.values() for i in v]) if groups else np.array([], int) | |
| rest = np.setdiff1d(np.arange(len(faces)), assigned) | |
| if len(rest): | |
| bound = UsdShade.MaterialBindingAPI(p).ComputeBoundMaterial()[0] | |
| groups.setdefault(str(bound.GetPath()) if bound else None, []).append(rest) | |
| parent, base_name = p.GetParent().GetPath(), p.GetName() | |
| local = UsdGeom.Xformable(p).GetLocalTransformation() | |
| ru.remove(layer, p.GetPath()) | |
| for k, (material, parts) in enumerate(sorted(groups.items(), key=lambda kv: str(kv[0]))): | |
| idx = np.concatenate(parts) | |
| pts, fcs = ru.weld(points, faces[idx]) | |
| used, remap = np.unique(fcs, return_inverse=True) | |
| pts, fcs = pts[used], remap.reshape(-1, 3) | |
| before += len(fcs) | |
| if len(fcs) > 200: | |
| pts, fcs = fast_simplification.simplify(pts.astype(np.float32), fcs.astype(np.int32), target_reduction=1 - KEEP) | |
| pts = pts.astype(np.float64) | |
| after += len(fcs) | |
| pts, fcs, normals = ru.crease_normals(pts, np.asarray(fcs, dtype=np.int64)) | |
| name = base_name if len(groups) == 1 else f"{base_name}_{k}" | |
| made = ru.author_mesh(stage, str(parent.AppendChild(name)), pts, fcs, normals, material) | |
| made.AddTransformOp().Set(local) | |
| # The trail tips, where the URDF puts them. Bodies may use other frame conventions than the URDF | |
| # links, so the URDF is placed by a best fit of every shared link origin. | |
| rest = ru.urdf_fk(URDF, {}) | |
| cache = UsdGeom.XformCache() | |
| names = {p.GetName(): p for p in stage.Traverse() if p.HasAPI(UsdPhysics.RigidBodyAPI)} | |
| shared = [l for l in rest if l in names] | |
| src = np.array([rest[l][:3, 3] for l in shared]) | |
| dst = np.array([ru.np_matrix(cache.GetLocalToWorldTransform(names[l]))[:3, 3] for l in shared]) | |
| cs, cd = src.mean(0), dst.mean(0) | |
| U, _, Vt = np.linalg.svd((src - cs).T @ (dst - cd)) | |
| R = (U @ Vt).T | |
| if np.linalg.det(R) < 0: | |
| Vt[-1] *= -1 | |
| R = (U @ Vt).T | |
| align = np.eye(4) | |
| align[:3, :3] = R | |
| align[:3, 3] = cd - R @ cs | |
| for side in SIDES: | |
| ru.add_frame(stage, f"{root}/openarm_{side}_hand", f"openarm_{side}_hand_tcp", align @ rest[f"openarm_{side}_hand_tcp"]) | |
| layer.documentation = ( | |
| "OpenArm bimanual for LeRobot. Modified by LeRobot from NVIDIA Isaac Sim 6.0 Robots/OpenArm/openarm_bimanual " | |
| "(Apache-2.0): flattened into one layer; sensors, render settings and colliders removed; the ee_tcp bodies " | |
| "replaced by the URDF's hand_tcp frames; link7-to-hand joints made fixed and renamed, and the body link renamed, " | |
| "to match the openarm_bimanual URDF; OmniPBR materials converted to UsdPreviewSurface; visual meshes decimated." | |
| ) | |
| layer.customLayerData = { | |
| "lerobot:source": "https://omniverse-content-production.s3-us-west-2.amazonaws.com/Assets/Isaac/6.0/Isaac/Robots/OpenArm/openarm_bimanual/openarm_bimanual.usd", | |
| "lerobot:urdf": "https://huggingface.co/buckets/lerobot/robot-urdfs/resolve/openarm/openarm_bimanual_web.urdf", | |
| } | |
| layer.Export(OUT) | |
| out = Usd.Stage.Open(OUT) | |
| report = ru.check_against_urdf(out, URDF) | |
| report["visual_bounds_vs_source_mm"] = ru.compare_visual_bounds(Usd.Stage.Open(SOURCE), out, {"openarm_body_link": "openarm_body_link0"}) | |
| report["triangles"] = {"before": before, "after": after} | |
| report["meshes"] = sum(1 for p in out.Traverse() if p.IsA(UsdGeom.Mesh)) | |
| report["fit_residual_mm"] = float(np.abs((R @ src.T).T + align[:3, 3] - dst).max() * 1000) | |
| print(json.dumps(report, indent=1, default=str)) | |