This project is a XML schema for validation of MJCF files. It relies on the use of XSD files and is relevant for MuJoCo 2.0 .
MJCF (namely MuJoCo's XML modeling format) is MuJoCo's native XML file format for describing models. It is an alternative to the more common URDF format.
For more details about MuJoCo and why MJCF format should be preferred to URDF using that library, see 1. .
XSD validation eases the writing of XML file, and can significantly improve your development efficiency. Basically, when a XSD validator is linked with a given XML file, that XSD file will check that that XML file respects the syntax it defines.
More concretely, XSD validation allows (among other things) autocompletion of elements and attributes, type checking of attributes as well as validation of nesting rules between elements.
For more details about the (almost unlimited) power of XSD validation, see 2.
Simply git clone the project to a convenient place (for example nearby the folder where MuJoCo is installed).
NB: One recommends not to modify the structure of the project. If you decide to do so, you will have to adapt import paths (see Project Structure paragraph below for further information).
The mujoco.xsd file is the main file of the project. Therefore, it is the only file you need to link with your MJCF files so as to allow validation.
There are several ways to link a XSD validator to a given XML file, see for example 3. .
Usually, a simple way is to add the following tag at the beginning of your MJCF-XML files:
<?xml-model href="relative/path/to/mujoco.xsd"?>
NB: Most of XML plugins also allow to enable XSD validation for a whole directory/project without additional tag. Therefore, if you use such a plugin, you are strongly encouraged to check its documentation!
The organisation of this project is mapped to MJCF syntax. To access complete MJCF syntax documentation, see 4. .
As mentionned before, the main file of the project is mujoco.xsd . It is located at the root of the project. It defines the relationships between elements of the MJCF syntax.
The attributes of elements are not defined in mujoco.xsd: they are imported from files located in the element_types folder. Each direct child of the <mujoco> root element has got its own file. For example, the <asset> element has got its element_types/asset.xsd file.
Each attribute is typed. So as to pool the defintion of types, all attribute types are located in the attribute_types/attribute_types.xsd file. At the head of that file, all shared types are stacked.
The type corresponding to the element/attribute X is by convention named XType.
In case of ambiguity, one can concatenate the name of the parent Y, so that it becomes YXType.
This project was originally written by a XSD validation noob, so it would be cool if you can help to improve it!
Don't hesitate to report issues or open your own PRs!
Some potential improvements I foresee:
- Fixing typos and reporting errors
- Improve attribute typing, especially when it comes to sequences of
float/int. - This ReadMe was not written by a native English speaker, so it is probably full of mistakes...
- MuJoCo - Overview: http://www.mujoco.org/book/index.html
- W3C - XSD Documentation: https://www.w3.org/TR/xmlschema11-1/
- RedHat XML - Validation: https://github.com/redhat-developer/vscode-xml/blob/master/docs/Validation.md
- MuJoCo - XML Reference: http://www.mujoco.org/book/XMLreference.html
- ronansgd 🇫🇷