Convert URDF to MuJoCo MJCF Without Installing Anything

If you've tried converting URDF to MuJoCo MJCF, you know the pain:

• MuJoCo's ./compile deletes fixed base links
• urdf2mjcf ignores off-diagonal inertia terms
• Mesh paths break constantly
• No automatic actuator generation

I built an API that handles all of this in one HTTP call.

One curl command

curl -X POST https://roboinfra-api.azurewebsites.net/api/urdf/convert-format?target=mjcf \
  -H "X-Api-Key: rk_your_key" \
  -F "file=@robot.urdf"

Real example

Input URDF (6 links, 5 joints):

Output MJCF:

Notice what the API auto-generated:

• Nested body tree (respects URDF kinematic chain)
• 4 motor actuators for movable joints (skipped fixed joint)
• Floor plane, lighting, compiler settings
• Half-extent box conversion (URDF 0.15 → MJCF 0.075)
• Continuous joint correctly mapped to unlimited hinge

Python SDK

pip install roboinfra-sdk

import roboinfra
client = roboinfra.Client("rk_your_key")
result = client.urdf.convert_format("robot.urdf", "mjcf")
with open("robot.xml", "w") as f:
    f.write(result.converted_xml)

Also converts to Gazebo SDF

Just change target=sdf:

curl -X POST .../api/urdf/convert-format?target=sdf \
  -H "X-Api-Key: rk_..." -F "file=@robot.urdf"

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