Mujoco

---------------------------

General
^^^^^^^
1. Renamed ``mjModel.tex_rgb`` to ``mjModel.tex_data``.
2. Added a new :ref:`autoreset<option-flag-autoreset>` flag to disable automatic reset when NaNs or infinities are
detected.
3. Added sub-elements to the MJCF :ref:`material<asset-material>` element, to allow specification of multiple textures
for rendering (e.g., ``occlusion, roughness, metallic``). Note that the MuJoCo renderer doesn't
support these new features, and they are made available for use with external renderers.
4. Sorting (``mjQUICKSORT``) now calls ``std::sort`` when building with C++ (:github:issue:`1638`).

MJX
^^^
5. Added more fields to ``mjx.Model`` and ``mjx.Data`` for further compatibility with the corresponding MuJoCo structs.
6. Added support for :ref:`fixed tendons <tendon-fixed>`.
7. Added support for tendon length limits (``mjCNSTR_LIMIT_TENDON`` in :ref:`mjtConstraint`).
8. Added support for tendon equality constraints (``mjEQ_TENDON`` in :ref:`mjtEq`).
9. Added support for tendon actuator transmission (``mjTRN_TENDON`` in :ref:`mjtTrn`).

Python bindings
^^^^^^^^^^^^^^^
10. Added support for asset dictionary argument in ``mujoco.spec.from_file``, ``mujoco.spec.from_string`` and
``mujoco.spec.compile``.


Bug fixes
^^^^^^^^^
11. Fixed a bug where implicit integrators did not take into account disabled actuators (:github:issue:`1838`).

----------------------------

New features
^^^^^^^^^^^^

1. Introduced a major new feature: **procedural model creation and editing**, using a new top-level data-structure
:ref:`mjSpec`. See the :doc:`Model Editing<programming/modeledit>` chapter for details.
Note that as of this release this feature is still in testing and subject to future breaking changes.
Fixes :github:issue:`364`.

General
^^^^^^^

.. admonition:: Breaking API changes
:class: attention

2. Removed deprecated ``mj_makeEmptyFileVFS`` and ``mj_findFileVFS`` functions. The constants ``mjMAXVFS`` and
``mjMAXVFSNAME`` are also removed as they are no longer needed.

**Migration:** Use :ref:`mj_addBufferVFS` to copy a buffer into a VFS file directly.

3. Calls to :ref:`mj_defaultVFS` may allocate memory inside VFS, and the corresponding
:ref:`mj_deleteVFS` must be called to deallocate any internal allocated memory.

4. Deprecated ``mju_rotVecMat`` and ``mju_rotVecMatT`` in favor of :ref:`mju_mulMatVec3` and
:ref:`mju_mulMatTVec3`. These function names and argument order are more consistent with the rest of the API.
The older functions have been removed from the Python bindings and will be removed from the C API in the next
release.
5. Removed the ``actuator_actdim`` callback from actuator plugins. They now have the ``actdim`` attribute, which
must be used with actuators that write state to the ``act`` array. This fixed a crash which happend when
keyframes were used in a model with stateful actuator plugins. The PID plugin will give an error when the wrong
value of actdim is provided.

6. Added :ref:`attach<body-attach>` meta-element to MJCF, which allows :ref:`attaching<meAttachment>` a subtree from a
different model to a body in the current model.
7. The :ref:`VFS<Virtualfilesystem>` implementation has been rewritten in C++ and is now considerably more efficient in
speed and memory footprint.

.. youtube:: ZXBTEIDWHhs
:align: right
:width: 240px

8. Added support for orthographic cameras. This is available for both fixed cameras and the free camera, using the
:ref:`camera/orthographic<body-camera-orthographic>` and :ref:`global/orthographic<visual-global-orthographic>`
attributes, respectively.
9. Added :ref:`maxhullvert<asset-mesh-maxhullvert>`, the maximum number of vertices in a mesh's convex hull.
10. Added :ref:`mj_setKeyframe` for saving the current state into a model keyframe.
11. Added support for ``ball`` joints in the URDF parser ("spherical" in URDF).
12. Replaced ``mjUSEDOUBLE`` which was previously hard-coded in
`mjtnum.h <https://github.com/google-deepmind/mujoco/blob/main/include/mujoco/mjtnum.h>`__
with the build-time flag ``mjUSESINGLE``. If this symbol is not defined, MuJoCo will use double-precision floating
point, as usual. If ``mjUSESINGLE`` is defined, MuJoCo will use single-precision floating point. See :ref:`mjtNum`.

Relatedly, fixed various type errors that prevented building with single-precision.
13. Quaternions in ``mjData.qpos`` and ``mjData.mocap_quat`` are no longer normalized in-place by
:ref:`mj_kinematics`. Instead they are normalized when they are used. After the first step, quaternions in
``mjData.qpos`` will be normalized.
14. Mesh loading in the compiler, which is usually the slowest part of the loading process, is now multi-threaded.

MJX
~~~
15. Added support for :ref:`elliptic friction cones<option-cone>`.
16. Fixed a bug that resulted in less-optimal linesearch solutions for some difficult constraint settings.
17. Fixed a bug in the Newton solver that sometimes resulted in less-optimal gradients.


.. youtube:: P83tKA1iz2Y
:align: right
:width: 360px

Simulate
^^^^^^^^
18. Added improved tutorial video.
19. Improved the Brownian noise generator.
20. Now displaying model load times if they are longer than 0.25 seconds.

Python bindings
^^^^^^^^^^^^^^^
21. Fixed a memory leak when using ``copy.deepcopy()`` on a ``mujoco.MjData`` instance (:github:issue:`1572`).

Bug fixes
^^^^^^^^^
22. Fix an issue where ``mj_copyData`` (or ``copy.copy()`` in the Python bindings) was not copying contact information
correctly (:github:issue:`1710`).
23. Fix an issue with saving to XML that caused frames to be written multiple times (:github:issue:`1802`).

---------------------------

General
^^^^^^^

1. Added :ref:`mj_geomDistance` for computing the shortest signed distance between two geoms and optionally a segment
connecting them. Relatedly, added the 3 sensors: :ref:`distance<sensor-distance>`, :ref:`normal<sensor-normal>`,
:ref:`fromto<sensor-fromto>`. See the function and sensor documentation for details. Fixes :github:issue:`51`.
2. Improvements to position actuators:

- Added :ref:`timeconst<actuator-position-timeconst>` attribute to the :ref:`position actuator<actuator-position>`.
When set to a positive value, the actuator is made stateful with :at:`filterexact` dynamics.
- Added :ref:`dampratio<actuator-position-dampratio>` to both :el:`position` and :el:`intvelocity` actuators. An
alternative to the :at:`kv` attribute, it provides a convenient way to set actuator damping using natural units.
See attribute documentation for details.

MJX
^^^

3. Add height-field collision support. Fixes :github:issue:`1491`.
4. Add a pre-compiled field ``mesh_convex`` to ``mjx.Model`` so that mesh properties can be vmapped over.
Fixes :github:issue:`1655`.
5. Fix a bug in convex mesh collisions, where erroneous edge contacts were being created even though face
separating axes were found. Fixes :github:issue:`1695`.

Bug fixes
^^^^^^^^^

6. Fixed a bug the could cause collisions to be missed when :ref:`fusestatic<compiler-fusestatic>` is enabled, as is
often the case for URDF imports. Fixes :github:issue:`1069`, :github:issue:`1577`.
7. Fixed a bug that was causing the visualization of SDF iterations to write outside the size of the vector storing
them. Fixes :github:issue:`1539`.

---------------------------

General
^^^^^^^

.. youtube:: 5k0_wsIRAFc
:align: right
:width: 240px

1. Added the :ref:`replicate<replicate>` to MJCF, a :ref:`meta-element<meta-element>` which permits to repeat a subtree
with incremental translational and rotational offsets.
2. Enabled an internal cache in the MuJoCo compiler resulting in recompilation speedup. Currently, processed
textures, hfields, and OBJ meshes are cached. Support for Unity environments is not yet available.
3. Added ``mjModel.mesh_scale``: the scaling applied to asset vertices, as specified in the
:ref:`scale<asset-mesh-scale>` attribute.
4. Added visual properties which are ignored by the native renderer, but can be used by external renderers:

- :ref:`light/bulbradius<body-light-bulbradius>` attribute and corresponding ``mjModel.light_bulbradius`` field.
- :ref:`material/metallic<asset-material-metallic>` attribute and corresponding ``mjModel.material_metallic`` field.
- :ref:`material/roughness<asset-material-roughness>` attribute and corresponding ``mjModel.material_roughness``
field.
5. The type of the ``size`` argument of :ref:`mj_stackAllocNum` and :ref:`mj_stackAllocInt` was changed from ``int``
to ``size_t``.
6. Added support for gmsh format version 2.2 surface meshes in :ref:`flexcomp<body-flexcomp-file>`.

MJX
^^^
.. admonition:: Breaking API changes
:class: attention

7. Removed deprecated ``mjx.device_get_into`` and ``mjx.device_put`` functions as they lack critical new
functionality.

**Migration:** Use ``mjx.get_data_into`` instead of ``mjx.device_get_into``, and ``mjx.put_data`` instead of
``mjx.device_put``.

8. Added cylinder plane collisions.
9. Added ``efc_type`` to ``mjx.Data`` and ``dim``, ``efc_address`` to ``mjx.Contact``.
10. Added ``geom`` to ``mjx.Contact`` and marked ``geom1``, ``geom2`` deprecated.
11. Added ``ne``, ``nf``, ``nl``, ``nefc``, and ``ncon`` to ``mjx.Data`` to match ``mujoco.MjData``.
12. Given the above added fields, removed ``mjx.get_params``, ``mjx.ncon``, and ``mjx.count_constraints``.
13. Changed the way meshes are organized on device to speed up collision detection when a mesh is replicated for many
geoms.
14. Fixed a bug where capsules might be ignored in broadphase colliision checking.
15. Added cylinder collisions using SDFs.
16. Added support for all :ref:`condim <coContact>`: 1, 3, 4, 6.
17. Add support functions for ``id2name`` and ``name2id``, MJX versions of :ref:`mj_id2name` and :ref:`mj_name2id`.
18. Added support for :ref:`gravcomp<body-gravcomp>` and :ref:`actuatorgravcomp<body-joint-actuatorgravcomp>`.
19. Fixed a bug in ``mjx.ray`` for sometimes allowed negative distances for ray-mesh tests.
20. Added a new `differentiable physics tutorial <https://colab.research.google.com/github/google-deepmind/mujoco/blob/main/mjx/training_apg.ipynb>`__ that demonstrates training locomotion policies with analytical gradients
automatically derived from the MJX physics step. Contribution by :github:user:`Andrew-Luo1`.

Bug fixes
^^^^^^^^^
21. Defaults of lights were not being saved, now fixed.
22. Prevent overwriting of frame names by body names when saving an XML. Bug introduced in 3.1.4.
23. Fixed bug in Python binding of :ref:`mj_saveModel`: ``buffer`` argument was documented as optional but was actually
not optional.
24. Fixed bug that prevented memory allocations larger than 2.15 GB. Fixes :github:issue:`1606`.

--------------------------------

General
^^^^^^^
.. admonition:: Breaking API changes
:class: attention

1. Removed the ability to natively add noise to sensors. Note that the ``mjModel.sensor_noise`` field and
:ref:`corresponding attribute<CSensor>` are kept and now function as a convenient location for the user to save
standard-deviation information for their own use. This feature was removed because:

- There was no mechanism to seed the random noise generator.
- It was not thread-safe, even if seeding would have been provided, sampling on multiple threads would lead to
non-reproducible results.
- This feature was seen as overreach by the engine. Adding noise should be the user's responsibility.
- We are not aware of anyone who was actually using the feature.

**Migration:** Add noise to sensor values yourself.

2. Added the :ref:`actuatorgravcomp<body-joint-actuatorgravcomp>` joint attribute. When enabled, gravity compensation
forces on the joint are treated as applied by actuators. See attribute documentation for more details. The example
model
`refsite.xml <https://github.com/google-deepmind/mujoco/blob/main/test/engine/testdata/actuation/refsite.xml>`__,
which demostrates Cartesian actuation of an arm, has been updated to use this attribute.
3. Added support for gmsh format 2.2 , tetrahedral mesh, as generated by e.g. `fTetwild <https://github.com/wildmeshing/fTetWild>`__.

4. Added :ref:`mju_euler2Quat` for converting an Euler-angle sequence to quaternion.

MJX
^^^
5. Improved performance of SAT for convex collisions.
6. Fixed bug for sphere/capsule-convex deep penetration.
7. Fixed bug where ``mjx.Data`` produced by ``mjx.put_data`` had different treedef than ``mjx.make_data``.
8. Throw an error for margin/gap for convex mesh collisions, since they are not supported.
9. Added ellipsoid plane collisions.
10. Added support for userdata.
11. Added ellipsoid-ellipsoid and ellipsoid-capsule collisions using signed distance functions (SDFs).

Simulate
^^^^^^^^
12. Fixed bug in order of enable flag strings. Before this change, using the simulate UI to toggle the
:ref:`invdiscrete<option-flag-invdiscrete>` or the (now removed) ``sensornoise`` flags would actually toggle the
other flag.

Python bindings
^^^^^^^^^^^^^^^

.. youtube:: xHDS0n5DpqM
:align: right
:width: 240px

13. Added the ``mujoco.minimize`` Python module for nonlinear least-squares, designed for System Identification (sysID).
The sysID tutorial is work in progress, but a pedagogical colab notebook with examples, including Inverse
Kinematics, is available here: |ls_colab|
|br| The video on the right shows example clips from the tutorial.

.. |ls_colab| image:: https://colab.research.google.com/assets/colab-badge.svg
:target: https://colab.research.google.com/github/google-deepmind/mujoco/blob/main/python/least_squares.ipynb

-------------------------------

General
^^^^^^^
1. Added the :at:`inheritrange` attribute to :ref:`position<actuator-position>` and
:ref:`intvelocity<actuator-intvelocity>` actuators, allowing convenient setting of the actuator's
:at:`ctrlrange` or :at:`actrange` (respectively), according to the range of the transmission
target (joint or tendon). See :ref:`position/inheritrange<actuator-position-inheritrange>` for
details.
2. Deprecated ``mj_makeEmptyFileVFS`` in favor of :ref:`mj_addBufferVFS`. :ref:`mjVFS` now computes checksums of
its internal file buffers. :ref:`mj_addBufferVFS` allocates an empty buffer with a given name in an mjVFS and
copies the data buffer into it, combining and replacing the deprecated two-step process of calling
``mj_makeEmptyFileVFS`` followed by a direct copy into the given mjVFS internal file buffer.
3. Added :ref:`mj_angmomMat` which computes the ``3 x nv`` angular momentum matrix :math:`H(q)`, providing the linear
mapping from generalized velocities to subtree angular momentum :math:`h = H \dot q`. Contribution by
:github:user:`v-r-a`.

MJX
^^^
4. Improved performance of getting and putting device data.

- Use ``tobytes()`` for numpy array serialization, which is orders of magnitude faster than converting to tuples.
- Avoid reallocating host ``mjData`` arrays when array shapes are unchanged.
- Speed up calculation of ``mjx.ncon`` for models with many geoms.
- Avoid calling ``mjx.ncon`` in ``mjx.get_data_into`` when ``nc`` can be derived from ``mjx.Data``.
5. Fixed a bug in ``mjx-viewer`` that prevented it from running. Updated ``mjx-viewer`` to use newer
``mjx.get_data_into`` function call.
6. Fixed a bug in ``mjx.euler`` that applied incorrect damping when using dense mass matrices.
7. Fixed a bug in ``mjx.solve`` that was causing slow convergence when using ``mjSOL_NEWTON`` in :ref:`mjtSolver`.
8. Added support for :ref:`mjOption.impratio<mjOption>` to ``mjx.Model``.
9. Added support for cameras in ``mjx.Model`` and ``mjx.Data``. Fixes :github:issue:`1422`.
10. Added an implementation of broadphase using `top_k` and bounding spheres.

Python bindings
^^^^^^^^^^^^^^^
11. Fixed incorrect data types in the bindings for the ``geom``, ``vert``, ``elem``, and ``flex`` array members
of the ``mjContact`` struct, and all array members of the ``mjrContext`` struct.