USDA File Format (.usda)
A USDA file holds a USD scene written out as plain UTF-8 text, spelling out every prim, attribute and layer composition line by line, in the encoding Universal Scene Description calls its ASCII form.
USDA at a glance#
| Full name | USD ASCII |
|---|---|
| File extension | .usda |
| Category | 3D Models |
| Developer | Pixar Animation Studios |
| First released | 2016 |
| MIME types | model/vnd.usda |
| Compression | Lossless |
| FileFlip support | FileFlip reads and writes this format |
What a .usda file can hold#
These are the things a USDA file either supports or does not, and they are what decides whether a conversion keeps everything or quietly drops something.
| Animation | Yes |
|---|---|
| Layers | Yes |
| Embedded metadata | Yes |
| Textures and materials | Yes |
| Skeletons and animation | Yes |
| Human readable | Yes |
| Comments | Yes |
| Schema or validation | Yes |
Strengths and limitations of USDA#
What USDA does well
- Readable and diffable in any text editor or version control system, unlike the binary Crate form
- Nothing is hidden: every prim, attribute and layer arc is spelled out rather than packed into an opaque binary blob
- Exactly the same data model as USDC, so nothing is lost by choosing the text encoding
Where USDA falls short
- Much larger on disk and slower to parse than the equivalent .usdc file
- Impractical for the dense point caches, animation curves and simulation data production scenes generate
Use USDA while authoring or debugging a layer by hand, or whenever a file needs to go through text-based diff and review.
Convert USDA to USDC once a layer is finished and only needs to load fast, not be read by a person.
How to open a .usda file#
A .usda file opens in the programs below, grouped by the platform you are on. If you would rather not install anything, FileFlip converts USDA into a format your machine already opens, and it does it in the browser tab rather than on a server.
| Platform | Programs that open it |
|---|---|
| Windows | Visual Studio Code, Blender, Autodesk Maya |
| macOS | Visual Studio Code, usdview, Blender, Autodesk Maya |
| Linux | Visual Studio Code, usdview, Blender |
| Web | FileFlip |
USDA questions people ask#
What does a USDA file look like inside?
A USDA file is plain text starting with a line like #usda 1.0, followed by prims declared with curly-brace blocks holding their typed attributes, much like a structured configuration file. Any text editor shows it exactly as written.
Why would I use USDA instead of USDC?
Choose USDA when a USD layer needs to be readable, hand-edited or diffed in version control, since USDC's binary Crate encoding gives none of that. USDC wins on load speed and file size once the layer is finished and only needs to be consumed by software.
Can I edit a USDA file by hand?
Yes. Because USDA is plain UTF-8 text, changing an attribute value or adding a prim is a normal text edit, and the result is still a valid USD layer as long as the syntax stays correct.
Converting USDA files#
Convert USDA to another format
Convert another format to USDA
- 3DS to USDA
- 3MF to USDA
- AC3D to USDA
- AC3D Scene to USDA
- ACC to USDA
- AMF to USDA
- ASE to USDA
- ASK to USDA
- B3D to USDA
- BLEND to USDA
- BSP to USDA
- BVH to USDA
- COB to USDA
- COLLADA to USDA
- CSM to USDA
- DirectX X to USDA
- DXF to USDA
- ENFF to USDA
- FBX to USDA
- GLB to USDA
- glTF to USDA
- HMP to USDA
- IFC to USDA
- IQM to USDA
See every 3D model conversion (40 more)
Every conversion runs inside your browser. The file is read from your disk, the work happens on your own machine, and nothing is uploaded. How FileFlip works names the engine behind each family and how to verify that for yourself.