Qt components for building custom USD tools

The UI components that make up usdview are good reference for functionality, but they’re purpose-built for the application, and are implemented in ways that make them difficult to decouple from it.

This project is meant to provide application components that can provide similar (as well as new) functionality, to allow for ad-hoc use in custom tools.

Longer-term, we hope this project will grow to the point that it can be used to build a fully-functional usdview application.

This project contains a mixture of pure Python and wrapped C++ code. All Qt code is written in pure Python to avoid the need to link against Qt and get moc involved in the build process. This may change in the future if deemed beneficial/necessary.

The compiled extension module provides a set of helper classes that interface with the USD C++ API to accelerate certain USD queries, operations, etc.

• pxr.UsdQt: Contains various Qt item data models, helper classes for building UIs, and some other USD and Qt utility code. The _bindings module currently contains all of the wrapped classes from the compiled extension module.
• pxr.UsdQtEditors: Contains various Qt UI elements. These range from purpose-built display/editor widgets to an extensible outliner UI that also serves as a good usage example for many of the utilities in pxr.UsdQt.
• treemodel: Contains a generic item tree and a Qt item model mixin that uses it, which are used by some of the classes in pxr.UsdQt.

The recommended (and currently only tested) way to build the project is using CMake. A setup.py file is provided as well, but it has not been tested with the most recent updates.

• Boost Python
• USD
• TBB

• INSTALL_PURE_PYTHON (BOOL): Whether to install the pure Python code in addition to the compiled extension module. This defaults to ON.

You may notice that the source contains UsdQt.py and UsdQtEditors.py files alongside the package source directories. These are "shim" modules that we've found to be very useful during the development of this project, as they enable us to do more rapid editing and testing on the pure Python code without needing to run a CMake build and install between each minor edit. They are not installed with the project.

UsdQt expects the Qt API it uses to supply the PySide5/Qt5 module layout.

By default, it will attempt to import and use PySide2. This can be overridden by setting the PXR_QT_PYTHON_BINDING environment variable to the name of the API package/module you wish to use instead.

This works with the popular Qt.py project.