Universal Scene Description
Learn
Introduction to USD
Terms and Concepts
Tutorials
Hello World - Creating Your First USD Stage
Hello World Redux - Using Generic Prims
Inspecting and Authoring Properties
Referencing Layers
Converting Between Layer Formats
Traversing a Stage
Authoring Variants
Variants Example in Katana
Transformations, Time-sampled Animation, and Layer Offsets
Simple Shading in USD
End to End Example
Houdini USD Example Workflow
Generating New Schema Classes
Creating a Usdview Plugin
Downloads and Videos
Products Using USD
User Guides
Rendering with USD
Configuring Imageable Content
Configuring the Stage Coordinate System
Understanding Render Visibility
Understanding Intrinsic and Explicit Normals
Working with Lights
Using Light-linking to Filter Objects Affected by Lights
Working with Materials
Using the USD Preview Material
Working with Primvars
Using Material Binding Purpose
Binding Materials to Collections
Using Material Render Contexts
Working With Image File Formats
Guidelines for All Supported Image Formats
JPEG
PNG
OpenEXR
Defining the Render Camera
Configuring Motion Blur
Configuring Render Settings
USD Variable Expressions
Defining Expression Variables in a Layer
string
bool
int64
<type>[]
None
Expression Variables and Composition
Authoring Variable Expressions
Expression Function Reference
defined(<variable name>, …)
if(<condition>, <true-value>, <false-value>)
if(<condition>, <true-value>)
and(<x>, <y>, …)
or(<x>, <y>, …)
not(<x>)
eq(<x>, <y>)
neq(<x>, <y>)
lt(<x>, <y>)
leq(<x>, <y>)
gt(<x>, <y>)
geq(<x>, <y>)
contains(<list_or_string>, <value>)
at(<list_or_string>, <index>)
len(<list_or_string>)
Examples
Flexible Variant Selections
Asset-valued Texture File Attribute
Conditionally Include Sublayers
Reference
API Documentation
Toolset
usdedit
usdcat
usddiff
usdview
usdrecord
usdresolve
usdtree
usdzip
usdchecker
usdfixbrokenpixarschemas
usdstitch
usdstitchclips
usddumpcrate
sdfdump
sdffilter
Specifications
UsdPreviewSurface Specification
Goal
Core Nodes
USD Sample
Other Notes
Changes, by Version
Usdz File Format Specification
Purpose
Usdz Specification
Packaging Considerations for Streaming and Encapsulation
MIME Type
Toolset
Proposals
Adapting UsdLux to Accommodate Geometry Lights
Introduction and Background
Design Space and Issues
UsdLux LightAPI OM
Proposal and Behaviors
Adapting UsdLux to the Needs of Renderers
Background and Goals
Foundational Technologies in USD
Proposals
Asset Previews in USD
Introduction
Proposal
Schema
Asset Resolution (Ar) 2.0
Background and Goals
Tasks
Rollout and Transition
Proposed API
Coordinate Systems in USD Proposal
Purpose
Requirements
Proposed API Schema
USD Sample and Analysis
Projections, Cameras, and CoordSysAPI
Generalizing Connectable Nodes Beyond UsdShade
Background and Goals
Proposal
Discussion
Render Settings in USD Proposal
Purpose and Scope
Overall Design and Concerns
Concrete Schemas
Prim and Scene Organization
Workflow Considerations
Examples
Discussion and Questions
Rigid Body Physics in USD Proposal
Purpose and Scope
Overall Design Concerns
Concrete Schemas
Examples
Schema Versioning in USD
Introduction
Proposal for Per-Schema Versioning
Risks, Questions, Limitations
Guidelines for Schema Versioning
Pixar Examples, Past and Future
Possible Code Generation Changes to Support Versioning
Stage Variable Expressions
UsdAudio Proposal
Goal
Initial Requirements
Proposed Prim Schema
USD Sample
Other Notes/Questions
UsdShade Material Assignment
Background
Basic Proposal for Collection-Based Assignment
Analysis of Collection-Based Binding
Integration
Remaining Questions
FAQ
General Questions
What is USD and why should I use it?
What programming languages are supported?
Isn’t USD just another file format?
So what file formats does USD support?
What file format is my
.usd
file?
What character encoding does
.usda
support?
How can I convert USD files between binary and text?
What data types are supported?
What does a USD file look like?
Subtler Aspects of Scene Description and Composition
I have some layers I want to combine: Should I use SubLayers or References?
What happens to “overs” when their underlying prim is moved to a different location in the scenegraph?
When can you delete a reference (or other deletable thing)?
What’s the difference between an “over” and a “typeless def” ?
Why Can’t I Instance a Leaf Mesh Prim Directly?
Build and Runtime Issues
Why Isn’t Python Finding USD Modules?
Why Isn’t This Plugin Being Built?
Why Isn’t My App Finding USD DLLs and Plugins on Windows?
Performance Considerations
Use an allocator optimized for multithreading
Use binary “.usd” files for geometry and shading caches
Package assets with payloads
What makes a USD scene heavy/expensive?
Third Party Plugins
RenderMan USD Imaging Plugin
Configuration
Developer
Alembic USD Plugin
Known Limitations
Collaborate
Source Code @ GitHub
OpenUSD Forum
Contributing
Contributor License Agreement
Coding Conventions
Pull Request Guidelines
Git Workflow
Github Issues
Contributors
Press
Open Source Release
Open Source Announcement
Universal Scene Description
API Documentation
API Documentation
USD C++ API Documentation