Get the Local Space Transforms for a Prim

If you need to get the local transformation of a prim (i.e. not taking into account the transformations of any ancestor prims), you can use a convenience function in Kit, omni.usd.get_local_transform_SRT(). Alternatively, you can use UsdGeom.Xformable.GetLocalTransformation() to get the local transformation matrix and decompose it into individual components.

USD Python

import typing
from pxr import Gf, Usd, UsdGeom

def get_local_transform_xform(prim: Usd.Prim) -> typing.Tuple[Gf.Vec3d, Gf.Rotation, Gf.Vec3d]:
    """
    Get the local transformation of a prim using Xformable.
    See https://openusd.org/release/api/class_usd_geom_xformable.html
    Args:
        prim: The prim to calculate the local transformation.
    Returns:
        A tuple of:
        - Translation vector.
        - Rotation quaternion, i.e. 3d vector plus angle.
        - Scale vector.
    """
    xform = UsdGeom.Xformable(prim)
    local_transformation: Gf.Matrix4d = xform.GetLocalTransformation()
    translation: Gf.Vec3d = local_transformation.ExtractTranslation()
    rotation: Gf.Rotation = local_transformation.ExtractRotation()
    scale: Gf.Vec3d = Gf.Vec3d(*(v.GetLength() for v in local_transformation.ExtractRotationMatrix()))
    return translation, rotation, scale


#############
# Full Usage
#############

from pxr import Sdf

# Create an in-memory Stage with /World Xform prim as the default prim
stage: Usd.Stage = Usd.Stage.CreateInMemory()
default_prim: Usd.Prim = UsdGeom.Xform.Define(stage, Sdf.Path("/World")).GetPrim()
stage.SetDefaultPrim(default_prim)

xform: Usd.Prim = UsdGeom.Xform.Define(stage, default_prim.GetPath().AppendPath("Xform"))
xform.AddTranslateOp().Set(value=(100,10,0))
xform.AddRotateXYZOp().Set(value=(0,50,0))
xform.AddScaleOp().Set(value=(5,5,5))

cube = UsdGeom.Cube.Define(stage, xform.GetPath().AppendPath("Cube"))
cube.AddTranslateOp().Set(value=(4,0,0))
cube.AddRotateXYZOp().Set(value=(100,0,0))
cube.AddScaleOp().Set(value=(2,2,2))

transform = get_local_transform_xform(cube)

usda = stage.GetRootLayer().ExportToString()
print(usda)

cube_prim = cube.GetPrim()

assert transform[0] == cube_prim.GetAttribute('xformOp:translate').Get()
assert (100,0,0) == cube_prim.GetAttribute('xformOp:rotateXYZ').Get()
assert transform[2] == cube_prim.GetAttribute('xformOp:scale').Get()

Python omni.usd

import typing
import omni.usd
from pxr import Usd, Gf

def get_local_transform_omni(prim: Usd.Prim) -> typing.Tuple[Gf.Vec3d, Gf.Rotation, Gf.Vec3d]:
    """
    Get the local transformation of a prim using omni.usd.get_local_transform_SRT.
    See https://docs.omniverse.nvidia.com/kit/docs/omni.usd/latest/omni.usd/omni.usd.get_local_transform_SRT.html
    Args:
        prim: The prim to calculate the local transformation.
    Returns:
        A tuple of:
        - Translation vector.
        - Rotation quaternion, i.e. 3d vector plus angle.
        - Scale vector.
    """
    local_transform = omni.usd.get_local_transform_SRT(prim)
    scale: Gf.Vec3d = local_transform[0]
    rotation: Gf.Vec3d = local_transform[1]
    rotation_order: float = local_transform[2]
    translation: Gf.Vec3d = local_transform[3]
    return translation, Gf.Rotation(rotation, rotation_order), scale

#############
# Full Usage
#############

import omni.kit.commands

# Create an Xform with a Cube Prim as it's Child
omni.kit.commands.execute('CreatePrimWithDefaultXform',
	prim_type='Xform',
	attributes={},
	select_new_prim=True)

omni.kit.commands.execute('TransformMultiPrimsSRTCpp',
	count=1,
	paths=['/World/Xform'],
	new_translations=[100, 0, 0],
	new_rotation_eulers=[0, 50 ,0],
	new_rotation_orders=[0, 1, 2],
	new_scales=[5, 5, 5],
	old_translations=[0.0, 0.0, 0.0],
	old_rotation_eulers=[0.0, 0.0, 0.0],
	old_rotation_orders=[0, 1, 2],
	old_scales=[1.0, 1.0, 1.0],
	usd_context_name='',
	time_code=0.0)

omni.kit.commands.execute('CreateMeshPrimWithDefaultXform',
	prim_type='Cube',
	prim_path='/World/Xform/Cube',
	select_new_prim=True,
	prepend_default_prim=False)

omni.kit.commands.execute('TransformMultiPrimsSRTCpp',
	count=1,
	paths=['/World/Xform/Cube'],
	new_translations=[4, 0, 0],
	new_rotation_eulers=[100, 0 ,0],
	new_rotation_orders=[0, 1, 2],
	new_scales=[2, 2, 2],
	old_translations=[0.0, 0.0, 0.0],
	old_rotation_eulers=[0.0, 0.0, 0.0],
	old_rotation_orders=[0, 1, 2],
	old_scales=[1.0, 1.0, 1.0],
	usd_context_name='',
	time_code=0.0)

stage = omni.usd.get_context().get_stage()
cube_prim = stage.GetPrimAtPath("/World/Xform/Cube")
transform = get_local_transform_omni(cube_prim)

assert transform[0] == cube_prim.GetAttribute('xformOp:translate').Get()
assert (100,0,0) == cube_prim.GetAttribute('xformOp:rotateXYZ').Get()
assert transform[2] == cube_prim.GetAttribute('xformOp:scale').Get()

USDA

This is an example USDA result from creating (and setting) float and float3 Attributes on the default Prim.

#usda 1.0
(
    defaultPrim = "World"
)

def Xform "World"
{
    def Xform "Xform"
    {
        float3 xformOp:rotateXYZ = (0, 50, 0)
        float3 xformOp:scale = (5, 5, 5)
        double3 xformOp:translate = (100, 10, 0)
        uniform token[] xformOpOrder = ["xformOp:translate", "xformOp:rotateXYZ", "xformOp:scale"]

        def Cube "Cube"
        {
            float3 xformOp:rotateXYZ = (100, 0, 0)
            float3 xformOp:scale = (2, 2, 2)
            double3 xformOp:translate = (4, 0, 0)
            uniform token[] xformOpOrder = ["xformOp:translate", "xformOp:rotateXYZ", "xformOp:scale"]
        }
    }
}