MJCF (MuJoCo XML Format)

The XML model format the MuJoCo simulator uses to describe robots and scenes.

MJCF is MuJoCo's native model format, describing a simulated scene in XML: rigid bodies are nested into a tree by parent-child relationships, and each body carries its joints, geoms (a sphere, box, or referenced mesh file), and mass and inertia; the format can also specify actuators, sensors, tendons, contact parameters, and the simulation time step. Compared with URDF, it can express more simulation-specific detail and is written more compactly. MuJoCo can also read URDF, but files are usually converted to MJCF and then given extra parameters. MuJoCo Menagerie, maintained by DeepMind, collects a large number of well-tuned robot MJCF models, and tools like MJX and MuJoCo Playground use the format directly.

ExampleThe unitree_g1 directory in MuJoCo Menagerie provides an MJCF file for the Unitree G1, which can be loaded directly into simulation for reinforcement-learning locomotion training.

Also called

MuJoCo XML

Related

MuJoCo (Multi-Joint dynamics with Contact) · Unified Robot Description Format · MuJoCo Menagerie · Mesh File (STL / OBJ / DAE / glTF) · Simulation Description Format (SDFormat) · Universal Scene Description (OpenUSD)

Sources

MuJoCo 文档：XML Reference (Chinese)
MuJoCo Menagerie GitHub