Compute the Bounding Box for a Prim

USD includes functions for computing the bounding box for a prim and all of its descendants. Bounding boxes are represented by the minimum point and maximum point of the bounding box. The two points form a diagonal across the interior of the box. These code samples show how to compute and retrieve a prim’s bounding box in world space.

USD Python

from pxr import Usd, UsdGeom, Gf

def compute_bbox(prim: Usd.Prim) -> Gf.Range3d:
    """
    Compute Bounding Box using ComputeWorldBound at UsdGeom.Imageable
    See https://openusd.org/release/api/class_usd_geom_imageable.html

    Args:
        prim: A prim to compute the bounding box.
    Returns: 
        A range (i.e. bounding box), see more at: https://openusd.org/release/api/class_gf_range3d.html
    """
    imageable = UsdGeom.Imageable(prim)
    time = Usd.TimeCode.Default() # The time at which we compute the bounding box
    bound = imageable.ComputeWorldBound(time, UsdGeom.Tokens.default_)
    bound_range = bound.ComputeAlignedBox()
    return bound_range

Alternatively, if you need to compute the bounding box for multiple prims on a stage, UsdGeom.BBoxCache is more efficient.

from pxr import Usd, UsdGeom, Gf

def compute_bbox_with_cache(cache: UsdGeom.BBoxCache, prim: Usd.Prim) -> Gf.Range3d:
    """
    Compute Bounding Box using ComputeWorldBound at UsdGeom.BBoxCache. More efficient if used multiple times.
    See https://openusd.org/release/api/class_usd_geom_b_box_cache.html
    
    Args:
        cache: A cached, i.e. `UsdGeom.BBoxCache(Usd.TimeCode.Default(), ['default', 'render'])`
        prim: A prim to compute the bounding box.
    Returns: 
        A range (i.e. bounding box), see more at: https://openusd.org/release/api/class_gf_range3d.html

    """
    bound = cache.ComputeWorldBound(prim)
    bound_range = bound.ComputeAlignedBox()
    return bound_range

Python omni.usd

import typing

import carb
import omni.usd

def compute_path_bbox(prim_path: str) -> typing.Tuple[carb.Double3, carb.Double3]:
    """
    Compute Bounding Box using omni.usd.UsdContext.compute_path_world_bounding_box
    See https://docs.omniverse.nvidia.com/kit/docs/omni.usd/latest/omni.usd/omni.usd.UsdContext.html#omni.usd.UsdContext.compute_path_world_bounding_box

    Args:
        prim_path: A prim path to compute the bounding box.
    Returns: 
        A range (i.e. bounding box) as a minimum point and maximum point.
    """
    return omni.usd.get_context().compute_path_world_bounding_box(prim_path)