.usda → .xml
USD to MJCF
Convert a robot description from USD to MJCF in the browser. Nothing is installed and nothing is queued: the file is read, written in the other format, and handed back with a list of anything that could not be carried across.
Convert a file
USD .usda MJCF .xml
Drop your USD here
Drop the folder too if the model references meshes.
Files are read on our server and deleted after a day. Nothing is published.
Reading the USD
Writing the MJCF
Look at the file first
What this conversion costs
These are the things MJCF has no place for. They are reported on the converted file as well, as a comment at the top, so the file itself says what is missing from it.
- Joint velocity limits. MJCF does not keep a velocity limit on the joint — MuJoCo enforces speed through actuators, so the number moves there or disappears.
- Fixed joints. MuJoCo has no fixed joint: the two bodies are merged, which is the right physics and a different file.
Isaac to MuJoCo, without either installed
The two ecosystems do not read each other's files. This is the direct route: a stage in, a model MuJoCo compiles out — and the physics lab on this site runs the result in the browser, so you can watch it stand before deciding whether the conversion was any good.
What MuJoCo needs that USD does not have
A ground plane, lights and solver settings are not in a robot description of any kind. Ask for a physics model and they are added, along with a free base for a robot with legs, because a legged robot welded to the origin can neither stand up nor fall over.
The two formats
- USD .usda
- NVIDIA's scene format, where a robot is ordinary geometry with UsdPhysics applied on top — what Isaac Sim opens. OpenUSD for robots
- MJCF .xml
- MuJoCo's own format: the same robot, plus everything a solver needs to simulate it. MJCF, explained
Converting is rarely the whole job. Once you have the MJCF, the viewer shows what actually came across — collision geometry against visual, joint limits, where the mass sits — and the physics lab answers the question a file cannot: whether the robot stands up when gravity is switched on.