chenlin/Mujoco_WASM
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Documentation pass for model editing, model encoding, and mjz.

Browse Source 
PiperOrigin-RevId: 951665744
Change-Id: I1dfe3b40f451cca686431c263815039a9c38efc8
This commit is contained in:
Sam Haves
2026-07-21 13:24:50 -07:00
committed by Copybara-Service
parent 259e6c4dc6
commit 1f1bfa9e4e
8 changed files with 226 additions and 127 deletions
Download Patch File Download Diff File Expand all files Collapse all files
doc/overview.rst
+12 -9
View File
@@ -166,31 +166,34 @@ There are several entities called "model" in MuJoCo. The user defines the model
The software can then create multiple instances of the same model in different media (file or memory) and on different
levels of description (high or low). All combinations are possible as shown in the following table:
+------------+---------------------------+----------------------------+
| | High level | Low level |
+============+===========================+============================+
| **File** | MJCF/URDF (XML) | MJB (binary) |
+------------+---------------------------+----------------------------+
| **Memory** | :ref:`mjSpec` (C struct) | :ref:`mjModel` (C struct) |
+------------+---------------------------+----------------------------+
+------------+-------------------------------------+----------------------------+
| | High level | Low level |
+============+=====================================+============================+
| **File** | MJCF/URDF (XML), MJZ (Zip archive) | MJB (binary) |
+------------+-------------------------------------+----------------------------+
| **Memory** | :ref:`mjSpec` (C struct) | :ref:`mjModel` (C struct) |
+------------+-------------------------------------+----------------------------+
All runtime computations are performed with :ref:`mjModel` which is too complex to create manually. This is why we have
two levels of modeling. The high level exists for user convenience: its sole purpose is to be compiled into a low level
model on which computations can be performed. The resulting :ref:`mjModel` can be loaded and saved into a binary file
(MJB), however those are version-specific and cannot be decompiled, thus models should always be maintained as XML
files.
files or packaged into MJZ archives.
The :ref:`mjSpec` C struct is in one-to-one correspondence with the MJCF file format. The XML loader interprets the MJCF
or URDF file, creates the corresponding :ref:`mjSpec` and compiles it to :ref:`mjModel`. The user can create
:ref:`mjSpec` programmatically and then save it to MJCF or compile it. Procedural model creation and editing is
:ref:`mjSpec` programmatically and then save it to MJCF/MJZ or compile it. Procedural model creation and editing is
described in the :doc:`Model Editing <programming/modeledit>` chapter.
The following diagram shows the different paths to obtaining an :ref:`mjModel`:
- (text editor) → MJCF/URDF file → (MuJoCo parser → mjSpec → compiler) → mjModel
- MJZ archive → (MJZ decoder → mjSpec → compiler) → mjModel
- (user code) → mjSpec → (MuJoCo compiler) → mjModel
- MJB file → (model loader) → mjModel
Models and specs can also be serialized or packaged back to disk using :ref:`mj_encode`.
.. _Examples:
Examples