# Notes on URDF and MJCF

It is important to note the slight differences between the URDF and MJCF formats to avoid bugs. In this writeup I will try to list down some common pitfalls on working with these two formats.

### Box size

URDF defines a box size with the three side lengths, while MJCF specifies **half-size** length.

<figure><img src="/files/cEEP8LAulLqvKmndKamC" alt=""><figcaption></figcaption></figure>


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