repository·dev·Indexed 21 days ago
https://github.com/autodesk/maya-usdA plugin for Autodesk Maya providing deep integration with OpenUSD. It enables loading USD stages directly into the Maya viewport for interactive editing and provides C++ and Python APIs for USD data manipulation. The plugin includes scripting commands for importing (mayaUSDImport) and exporting (mayaUSDExport) USD data, as well as tools for managing layers, prim schemas, and custom import chasers.
The repository is organized into several key functional areas:
| Location | Description |
|---|---|
lib | The core AL_USDMaya Library |
plugin | The Maya plugin and test plugin |
samples | Test inputs |
schemas | Maya-specific schemas with translators |
translators | Reference Schema Translator Plugins |
tutorials | Tutorials |
utils | Contains the event system (AL_EventSystem) |
mayautils | AL_MayaUtils (depends on Maya only) |
usdmayautils | AL_USDMayaUtils (depends on USD and Maya) |
The AL_MayaTest library is a testing framework for Maya-based code, specifically designed to wrap googletest. It is used to test AL_USDMaya translators and any other Maya plugin code. It consists of two primary modules:
The maya-usd plugin provides deep integration for OpenUSD within Autodesk Maya. It enables a modern, cross-DCC (Digital Content Creation) referencing pipeline, allowing data to flow between products like Maya and 3ds Max.
Key capabilities include:
The lib/AL_USDMaya/AL/maya module provides a collection of non-USD specific helper and convenience classes designed to reduce boilerplate when developing Maya plugins. Key utilities include:
Common.h: Macros for reducing boilerplate code.CommandGuiHelper.h: Automatically generates simple UIs from MPxCommands.DGNodeHelper.h: Utilities for getting/setting types on Dependency Graph (DG) Nodes.FileTranslatorBase.h: Macros and templates to automate the setup of Maya import/export plugins.FileTranslatorOptions.h: Utility for parsing file translator options passed by Maya.MenuBuilder.h: Generates menu entries for an entire plugin.NodeHelper.h: Functions for adding static/dynamic attributes to MPxNode, retrieving data from a MDataBlock, and AE (Attribute Editor) template generators.SIMD.h: Low-level SSE/AVX routines (not Maya-dependent).The Maya USD plugin provides several core modules for developers looking to extend or interact with USD within Maya. Key areas of functionality include:
UsdTransform3d).The OpUndo system is a C++ framework designed to support undo/redo operations across multiple heterogeneous frameworks used within the MayaUSD plugin (such as UFE, USD, OpenMaya, MEL, Python, and pure C++).
Important Distinction: OpUndo is not an undo/redo stack or an undo manager. It does not replace Maya's built-in undo system. Instead, it is a mechanism to record the specific individual steps (items) that need to be undone or redone so that Maya's undo system can trigger them correctly.
The AL_usd_ProxyUsdGeomCamera node acts as a bridge between a Maya camera and a USD UsdGeomCamera.
Its primary purpose is to allow interactive editing of USD camera attributes directly from Maya. Instead of duplicating data between Maya and USD, the proxy node reads from and writes directly to the USD camera attributes. When connected to a Maya camera, it drives the Maya camera attributes while simultaneously updating the underlying USD stage, ensuring both environments stay in sync.
AL_USDMaya is a USD-Maya bridge designed to represent Maya data in Maya and USD data in USD. It is specifically tailored for complex workflows where native Maya entities (like complex referenced rigs or assets not easily represented in USD) need to be embedded in USD scenes and imported into Maya in their native form.
Key capabilities include:
Mesh Translation is the process of moving Mesh information from USD/Hydra into Maya, allowing you to use Maya's native geometry manipulation tools, and then writing those changes back to USD/Hydra.
By default, Mesh typed prims are not automatically translated into Maya geometry when using a ProxyShape. To bring a mesh into Maya for editing, you must explicitly use the AL_usdmaya_TranslatePrim command.
By default, USD modifications in Maya are written to the current edit target (the layer selected in the Layer Editor). Edit routing is a mechanism that allows you to intercept these modifications and redirect them to a specific USD layer instead of the current target.
This is achieved by registering a routing function (an 'edit router') that receives information about the USD prim being modified and the operation being performed. The router can then return a specific layer ID or handle to redirect the edit. If the router returns nothing, the modification proceeds to the current targeted layer.
Animation export in usdExport uses two main parameters: -frameRange and -frameStride.
-ft): This is the primary way to control sampling density. A stride of 0.5 doubles the samples; a stride of 2.0 takes every other frame. Note that the last frame in the range might be skipped if the stride doesn't land exactly on it.-fs): An advanced option for fine-grained control. These samples are evaluated relative to the current time.Processing Order:
frameStride.Example Behavior:
If frameRange is [1, 3], frameStride is 1.0, and frameSample is [-0.1, 0.2], the exported time samples will be: 0.9, 1.2, 1.9, 2.2, 2.9, 3.2.
A Schema Translator is the primary mechanism used to map USD data into Maya forms. When the AL_USDMaya import functionality encounters a 'Typed' USDSchema that has a registered translator, it executes that translator to convert the USD data into Maya objects.
Capabilities of a Schema Translator include:
MayaReferences).Note: Currently, there is no support for USD export via translators.