Usage Examples

Reserve Changes for Undo on USD Layer

This example demonstrates creating a mesh prim, modifying an attribute, reserving the changes for undo, and then reverting those changes using the undo functionality provided by the UsdEditTargetUndo class.

from pxr import Usd, UsdGeom, Sdf
from omni.kit.usd_undo import UsdEditTargetUndo

# Open an existing stage or create a new one
stage = Usd.Stage.CreateNew("myStage.usda")
edit_target = stage.GetEditTarget()

# Create an instance of UsdEditTargetUndo for managing undo operations
usd_undo = UsdEditTargetUndo(edit_target)

# Make changes to the stage
mesh = UsdGeom.Mesh.Define(stage, "/Root/Mesh")
mesh.CreateNormalsAttr().Set([(1.0, 0.0, 0.0)])

# Reserve the changes for undo
usd_undo.reserve("/Root/Mesh.normals")

# Perform undo to revert the changes
usd_undo.undo()

# After undo, the layer should be reverted back to its state
# before the changes were made.

Reset Undo Stack for USD Layer

from pxr import Sdf, Usd
from omni.kit.usd_undo.layer_undo import UsdLayerUndo

# Open an existing USD stage
layer_path = "/path/to/existing/stage.usda"
stage = Usd.Stage.Open(layer_path)

# Create UsdLayerUndo for the root layer
usd_layer_undo = UsdLayerUndo(stage.GetRootLayer())

# Reset the undo stack for the layer
usd_layer_undo.reset()

# After reset, there will be no changes to undo.