How do I install the Urdf2mjcf skill?

Run npx skillmds@latest add plurigrid/urdf2mjcf in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Urdf2mjcf safe to use?

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Which AI agents work with Urdf2mjcf?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Urdf2mjcf free to use?

Yes. Installing skills from SkillMD is free. This skill is licensed under MIT.

Who published Urdf2mjcf?

plurigrid (@plurigrid) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Urdf2mjcf by plurigrid — Agent Skill

Name: Urdf2mjcf
Author: plurigrid

File contents

URDF2MJCF Skill

Trit: -1 (MINUS - analysis/transformation) Color: #4615B7 (Deep Violet) URI: skill://urdf2mjcf#4615B7

Overview

Convert URDF (Unified Robot Description Format) files to MJCF (MuJoCo XML Format) for simulation in MuJoCo and MJX. Handles meshes, joints, actuators, and collision geometries.

Usage

# CLI conversion
urdf2mjcf robot.urdf --output robot.mjcf

# With options
urdf2mjcf robot.urdf \
    --output robot.mjcf \
    --mesh-dir ./meshes \
    --add-actuators \
    --collision-margin 0.001

from urdf2mjcf import convert

# Programmatic conversion
mjcf_xml = convert(
    urdf_path="robot.urdf",
    mesh_dir="./meshes",
    add_actuators=True,
    collision_margin=0.001,
)

# Save to file
with open("robot.mjcf", "w") as f:
    f.write(mjcf_xml)

Features

Mesh Handling: Converts STL/OBJ meshes, scales appropriately
Joint Mapping: URDF revolute/prismatic → MJCF hinge/slide
Actuator Generation: Auto-generates position/velocity actuators
Collision Geometry: Convex decomposition, margin adjustment
Inertia Cleanup: Fixes common URDF inertia issues

Pipeline

┌─────────────┐    ┌─────────────┐    ┌─────────────┐
│  URDF File  │───▶│  urdf2mjcf  │───▶│  MJCF File  │
│  (ROS/SDF)  │    │  Converter  │    │  (MuJoCo)   │
└─────────────┘    └─────────────┘    └─────────────┘
       │                  │                  │
       ▼                  ▼                  ▼
   Meshes STL        Link transforms     Physics props
   Joint limits      Mass/inertia        Actuator defs
   Visual geom       Collision geom      Sensor defs

GF(3) Triads

urdf2mjcf (-1) ⊗ kos-firmware (+1) ⊗ mujoco-scenes (0) = 0 ✓

Related Skills

ksim-rl (-1): Uses converted MJCF for training
kos-firmware (+1): Robot firmware
mujoco-scenes (0): Scene composition
kbot-humanoid (-1): K-Bot robot model

References

@misc{urdf2mjcf2024,
  title={URDF to MJCF Converter},
  author={K-Scale Labs},
  year={2024},
  url={https://github.com/kscalelabs/urdf2mjcf}
}

SDF Interleaving

This skill connects to Software Design for Flexibility (Hanson & Sussman, 2021):

Primary Chapter: 7. Propagators

Concepts: propagator, cell, constraint, bidirectional, TMS

GF(3) Balanced Triad

urdf2mjcf (+) + SDF.Ch7 (○) + [balancer] (−) = 0

Skill Trit: 1 (PLUS - generation)

Connection Pattern

Propagators flow constraints bidirectionally. This skill propagates information.

---name: urdf2mjcfdescription: Convert URDF robot descriptions to MJCF format for MuJoCo simulation. Handles meshes, joints, actuators, and collision geometries.license: MIT---# URDF2MJCF Skill**Trit**: -1 (MINUS - analysis/transformation)**Color**: #4615B7 (Deep Violet)**URI**: skill://urdf2mjcf#4615B7## OverviewConvert URDF (Unified Robot Description Format) files to MJCF (MuJoCo XML Format) for simulation in MuJoCo and MJX. Handles meshes, joints, actuators, and collision geometries.## Usage```bash# CLI conversionurdf2mjcf robot.urdf --output robot.mjcf# With optionsurdf2mjcf robot.urdf \ --output robot.mjcf \ --mesh-dir ./meshes \ --add-actuators \ --collision-margin 0.001``````pythonfrom urdf2mjcf import convert# Programmatic conversionmjcf_xml = convert( urdf_path="robot.urdf", mesh_dir="./meshes", add_actuators=True, collision_margin=0.001,)# Save to filewith open("robot.mjcf", "w") as f: f.write(mjcf_xml)```## Features- **Mesh Handling**: Converts STL/OBJ meshes, scales appropriately- **Joint Mapping**: URDF revolute/prismatic → MJCF hinge/slide- **Actuator Generation**: Auto-generates position/velocity actuators- **Collision Geometry**: Convex decomposition, margin adjustment- **Inertia Cleanup**: Fixes common URDF inertia issues## Pipeline```┌─────────────┐ ┌─────────────┐ ┌─────────────┐│ URDF File │───▶│ urdf2mjcf │───▶│ MJCF File ││ (ROS/SDF) │ │ Converter │ │ (MuJoCo) │└─────────────┘ └─────────────┘ └─────────────┘ │ │ │ ▼ ▼ ▼ Meshes STL Link transforms Physics props Joint limits Mass/inertia Actuator defs Visual geom Collision geom Sensor defs```## GF(3) Triads```urdf2mjcf (-1) ⊗ kos-firmware (+1) ⊗ mujoco-scenes (0) = 0 ✓```## Related Skills- `ksim-rl` (-1): Uses converted MJCF for training- `kos-firmware` (+1): Robot firmware- `mujoco-scenes` (0): Scene composition- `kbot-humanoid` (-1): K-Bot robot model## References```bibtex@misc{urdf2mjcf2024, title={URDF to MJCF Converter}, author={K-Scale Labs}, year={2024}, url={https://github.com/kscalelabs/urdf2mjcf}}```## SDF InterleavingThis skill connects to **Software Design for Flexibility** (Hanson & Sussman, 2021):### Primary Chapter: 7. Propagators**Concepts**: propagator, cell, constraint, bidirectional, TMS### GF(3) Balanced Triad```urdf2mjcf (+) + SDF.Ch7 (○) + [balancer] (−) = 0```**Skill Trit**: 1 (PLUS - generation)### Connection PatternPropagators flow constraints bidirectionally. This skill propagates information.

Frequently asked questions

Urdf2mjcf