Overview#

The Skeleton Animation Property Widget extension integrates a suite of property widgets and commands into the Omniverse Kit property window. It enables users to view and modify skeletal animation properties—such as mesh-skeleton binding attributes, animation annotations, and animation sources—through dedicated UI components. The extension also provides command support for applying the USD Skel Binding API, complete with undo capabilities, ensuring that changes to skeletal properties can be managed safely.

Concepts#

Skeletal Property Management
The extension offers specialized widgets to handle various aspects of skeletal animation. These include interfaces for mesh binding attributes, annotation properties, and animation attributes to streamline the manipulation of skeletal data.
Command-Based Operations
It leverages a command framework to apply changes—such as binding application—across selected USD prims, with a built-in undo system that operates on USD layers.

Functionality#

Property Widgets
The widgets are designed to filter and display only relevant skeletal attributes, ensuring that users interact with key properties like skeleton references, skinning methods, and animation sources. They also support annotation tracking, either by expanding the tag list or maintaining bidirectional mappings based on user preferences.
Command Integration
Using a command, the extension applies the Skel Binding API to prims in the USD stage. This operation is reversible, allowing users to confidently modify skeletal properties and revert changes if needed.

Key Components#

UsdLayerUndo
Supports undo functionality by capturing state changes in the USD layers during skeletal binding operations.
ApplySkelBindingAPICommand
Implements a command to apply the USD Skel Binding API, iterating over selected prims and integrating with the undo mechanism.
MeshSkelBindingAttributesWidget
Extends the basic USD properties widget to present a tailored interface for adjusting mesh and skeleton binding properties.
SkelAnimationAnnotationPropertiesWidget & SkelAnimationAnnotationSchemeDelegate
Offer a user interface and a delegate mechanism to manage and validate annotation tags on skeletal animations, accommodating different tracking modes.
SkelAnimationAttributesWidget
Provides an enhanced UI for managing the ‘skel:animationSource’ property and other related animation attributes with custom behavior on user interaction and payload processing.

Relationships#

Dependencies
The extension builds upon several core Omniverse Kit modules such as omni.usd, omni.ui, omni.kit.window.property, and omni.kit.property.usd. It also relies on the command and undo systems provided by omni.kit.commands and omni.kit.usd_undo.
Integration
By integrating with the Omniverse Kit property window, the extension ensures that skeletal animation properties are accessible and editable in a consistent manner within the overall USD scene editing workflow.

Considerations#

This extension is designed to work within the Omniverse Kit ecosystem, so it depends on specific modules and systems (like USD and the property window).
The undo support provided by UsdLayerUndo is tailored for operations on USD layers, meaning that users should be aware of potential constraints when working with different layer setups.