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| """Compute the bottom offset of a USD asset. |
| |
| The bottom offset is the distance from the asset's origin to the lowest |
| point of any mesh in the USD file. This value is used to spawn objects |
| flush on the table surface. |
| |
| Usage: |
| python scripts_v2/tools/compute_bottom_offset.py /path/to/asset.usd |
| """ |
|
|
| import argparse |
| import numpy as np |
|
|
| from pxr import Usd, UsdGeom |
|
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|
|
| def get_world_points(mesh: UsdGeom.Mesh, time=Usd.TimeCode.Default()) -> np.ndarray: |
| """Get mesh vertices transformed to world space.""" |
| points = np.array(mesh.GetPointsAttr().Get(time), dtype=np.float64) |
| if len(points) == 0: |
| return points |
| xform = UsdGeom.Xformable(mesh.GetPrim()) |
| world_transform = xform.ComputeLocalToWorldTransform(time) |
| mat = np.array(world_transform, dtype=np.float64).T |
| ones = np.ones((len(points), 1), dtype=np.float64) |
| homogeneous = np.hstack([points, ones]) |
| return (homogeneous @ mat.T)[:, :3] |
|
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|
|
| def compute_bottom_offset(usd_path: str, verbose: bool = False) -> float: |
| """Compute distance from origin to lowest mesh vertex in the USD.""" |
| stage = Usd.Stage.Open(usd_path) |
| if not stage: |
| raise FileNotFoundError(f"Cannot open USD: {usd_path}") |
|
|
| all_points = [] |
| mesh_count = 0 |
| for prim in stage.Traverse(): |
| if prim.IsA(UsdGeom.Mesh): |
| mesh = UsdGeom.Mesh(prim) |
| pts = get_world_points(mesh) |
| if len(pts) > 0: |
| all_points.append(pts) |
| mesh_count += 1 |
|
|
| if not all_points: |
| raise ValueError(f"No meshes found in {usd_path}") |
|
|
| pts = np.vstack(all_points) |
| bbox_min = pts.min(axis=0) |
| bbox_max = pts.max(axis=0) |
| min_z = bbox_min[2] |
|
|
| if verbose: |
| print(f"Meshes found: {mesh_count}") |
| print(f"Total vertices: {len(pts)}") |
| print(f"Bounding box min: ({bbox_min[0]:.6f}, {bbox_min[1]:.6f}, {bbox_min[2]:.6f})") |
| print(f"Bounding box max: ({bbox_max[0]:.6f}, {bbox_max[1]:.6f}, {bbox_max[2]:.6f})") |
| size = bbox_max - bbox_min |
| print(f"Size: ({size[0]:.6f}, {size[1]:.6f}, {size[2]:.6f})") |
|
|
| return abs(min_z) |
|
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|
|
| def main(): |
| parser = argparse.ArgumentParser(description="Compute bottom offset of a USD asset.") |
| parser.add_argument("usd_path", type=str, help="Path to the USD file.") |
| parser.add_argument("-v", "--verbose", action="store_true", help="Print bounding box details.") |
| args = parser.parse_args() |
|
|
| offset = compute_bottom_offset(args.usd_path, verbose=args.verbose) |
| print(f"bottom_offset: {offset:.6f}") |
|
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|
|
| if __name__ == "__main__": |
| main() |
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|
