Universal Scene Description (ASCII) .usda
The readable flavour of USD. Plain text you can diff.
What a .usda file holds
A .usda file is Universal Scene Description in its human-readable text encoding. It is the flavour to reach for when you want to see what a scene actually declares, diff two revisions in source control, or hand-edit an override, at the cost of being far larger and slower to load than the binary crate format.
Commonly seen in: Houdini, Maya, usdview, Omniverse, Blender.
| Data | Stored in USDA |
|---|---|
| Geometry | Yes |
| Materials and colour | Yes |
| Texture maps | Yes |
| Animation and rigs | Yes |
| Scene hierarchy | Yes |
| Read here | Yes |
| Written here | Yes |
Tested against a real file
The last sweep loaded simple-skin-test.usda from Assimp test models through the viewer on this site: 32 triangles across 1 meshes and 1 materials, in 2.1 seconds. Every format's result is on the test results page, run 2026-09-08.
What we put in a .usda file we write
One flat layer holding geometry, per-mesh UsdPreviewSurface materials and texture coordinates, with nothing referenced from outside the file. Texture images are not written, because a .usda names an image by path rather than carrying it; USDZ is the packaged form of the same scene and does carry them. Animation is not written, and the scene is flattened to one Mesh prim per mesh with transforms baked in.
Convert USDA to another format
Every pairing has a page saying what survives the trip.
Convert something else to USDA
Other things to do with a .usda file
Questions about USDA
How do I open a .usda file?
Drop it into the viewer on this site and it opens in the browser, with the scene tree, the materials and the mesh statistics. Nothing is uploaded. If you want it in another program instead, convert it to GLB, which almost everything reads.
Is USDA a good format to archive in?
USDA carries geometry, materials, textures and animation, so an archive copy keeps nearly everything. The usual caveat applies: a format is only as future-proof as the readers that exist for it, and .usda is well served.
Does converting USDA lose quality?
Geometry is copied vertex for vertex, so the shape does not degrade. What gets lost is whatever the target format has no field for: convert to STL and the materials go, convert to OBJ and the animation goes. The comparison table on each converter page says exactly which.
Formats that hold the same things
Or go back to the full format reference.