Vc1tq0fFvQA
- Added constraint island discovery with
mj_island
. Constraint islands are disjoint sets of constraints and degrees-of-freedom that do not interact. The only solver which currently supports islands isCG<option-solver>
. Island discovery can be activated using a newenable flag<option-flag-island>
. If island discovery is enabled, geoms, contacts and tendons will be colored according to the corresponding island, see video.
QewlEqIZi1o
- Added new signed distance field (SDF) collision primitive. SDFs can take any shape and are not constrained to be convex. Collision points are found by minimizing the maximum of the two colliding SDFs via gradient descent.
- Added new SDF plugin for defining implicit geometries. The plugin must define methods computing an SDF and its gradient at query points. See the
documentation<exWriting>
for more details.
- Added new SDF plugin for defining implicit geometries. The plugin must define methods computing an SDF and its gradient at query points. See the
- Added
mjThreadPool
andmjTask
which allow for multi-threaded operations within the MuJoCo engine pipeline.
ra2bTiZHGlw
- Added capability to initialize
composite<body-composite>
particles with arbitrary positions. - Added shell passive force plugin:
- Collisions use spheres located at mesh vertices.
- Stretching as tendon constraints and bending using a constant precomputed Hessian (cotangent operator).
Breaking API changes
Removed the macros
mjMARKSTACK
andmjFREESTACK
.Migration: These macros have been replaced by new functions
mj_markStack
andmj_freeStack
. These functions manage themjData stack<siStack>
in a fully encapsulated way (i.e., without introducing a local variable at the call site).Renamed
mj_stackAlloc
tomj_stackAllocNum
. The new functionmj_stackAllocByte
allocates an arbitrary number of bytes and has an additional argument for specifying the alignment of the returned pointer.Migration: The functionality for allocating
mjtNum
arrays is now available viamj_stackAllocNum
.- Renamed the
nstack
field inmjModel
andmjData
tonarena
. Changednarena
,pstack
, andmaxuse_stack
to count number of bytes rather than number ofmjtNum
s. - Changed
mjData.solver<mjData>
, the array used to collect solver diagnostic information. This array ofmjSolverStat
structs is now of lengthmjNISLAND * mjNSOLVER
, interpreted as as a matrix. Each row of lengthmjNSOLVER
contains separate solver statistics for each constraint island. If the solver does not use islands, only row 0 is filled.- The new constant
mjNISLAND<glNumeric>
was set to 20. mjNSOLVER<glNumeric>
was reduced from 1000 to 200.- Added
mjData.solver_nisland<mjData>
: the number of islands for which the solver ran. - Renamed
mjData.solver_iter
tosolver_niter
. Both this member andmjData.solver_nnz
are now integer vectors of lengthmjNISLAND
.
- The new constant
Removed
mjOption.collision
and the associatedoption/collision
attribute.Migration:
- For models which have
<option collision="all"/>
, delete the attribute. - For models which have
<option collision="dynamic"/>
, delete allpair<contact-pair>
elements. - For models which have
<option collision="pair"/>
, disable all dynamic collisions (determined via contype/conaffinity) by first deleting allcontype<body-geom-contype>
andconaffinity<body-geom-conaffinity>
attributes in the model and then setting them globally to0
using<default> <geom contype="0" conaffinity="0"/> </default>
.
- For models which have
Removed the
rope
andcloth
composite objects.Migration: Users should use the
cable
andshell
elasticity plugins.
- Added a new
dyntype<actuator-general-dyntype>
,filterexact
, which updates first-order filter states with the exact formula rather than with Euler integration. - Added an actuator attribute,
actearly<actuator-general-actearly>
, which uses semi-implicit integration for actuator forces: using the next step's actuator state to compute the current actuator forces at the current timestep. - Renamed
actuatorforcerange
andactuatorforcelimited
, introduced in the previous version toactuatorfrcrange<body-joint-actuatorfrcrange>
andactuatorfrclimited<body-joint-actuatorfrclimited>
, respectively. - Added the flag
eulerdamp<option-flag-eulerdamp>
, which disables implicit integration of joint damping in the Euler integrator. See theNumerical Integration<geIntegration>
section for more details. - Added the flag
invdiscrete<option-flag-invdiscrete>
, which enables discrete-time inverse dynamics for allintegrators<option-integrator>
other thanRK4
. See the flag documentation for more details. - Added
ls_iterations<option-ls_iterations>
andls_tolerance<option-ls_tolerance>
options for adjusting linesearch stopping criteria in CG and Newton solvers. These can be useful for performance tuning. - Added
mesh_pos
andmesh_quat
fields tomjModel
to store the normalizing transformation applied to mesh assets. Fixes #409 . - Added camera
resolution<body-camera-resolution>
attribute andcamprojection<sensor-camprojection>
sensor. If camera resolution is set to positive values, the camera projection sensor will report the location of a target site, projected onto the camera image, in pixel coordinates. - Added
camera<body-camera>
calibration attributes:- The new attributes are
resolution<body-camera-resolution>
,focal<body-camera-focal>
,focalpixel<body-camera-focalpixel>
,principal<body-camera-principal>
,principalpixel<body-camera-principalpixel>
andsensorsize<body-camera-sensorsize>
. - Visualize the calibrated frustum using the
mjVIS_CAMERA<mjtVisFlag>
visualization flag when these attributes are specified. See the following example model. - Note that these attributes only take effect for offline rendering and do not affect interactive visualisation.
- The new attributes are
- Implemented reversed Z rendering and added enum
mjtDepthMap
with elementsmjDEPTH_ZERONEAR
andmjDEPTH_ZEROFAR
which can be used to setreadDepthMap
inmjrContext
to control how the depth returned bymjr_readPixels
is mapped fromznear
tozfar
.
- Fixed #870 where calling
update_scene
with an invalid camera name used the default camera.
- Fixed a bug that was causing
geom margin<body-geom-margin>
to be ignored during the construction of midphase collision trees.
- Added primitive collider for sphere-cylinder contacts, previously this pair used the generic convex-convex collider.
- Added
joint-actuatorforcerange<body-joint-actuatorfrcrange>
for clamping total actuator force at joints andsensor-jointactuatorfrc<sensor-jointactuatorfrc>
for measuring total actuation force applied at a joint. The most important use case for joint-level actuator force clamping is to ensure thatCartesian actuator<actuator-general-refsite>
forces are realizable by individual motors at the joints. SeeCForceRange
for details. - Added an optional
content_type
attribute to hfield, texture, and mesh assets. This attribute supports a formatted Media Type (previously known as MIME type) string used to determine the type of the asset file without resorting to pulling the type from the file extension. - Added analytic derivatives for quaternion
subtraction<mjd_subQuat>
andintegration<mjd_quatIntegrate>
(rotation with an angular velocity). Derivatives are in the 3D tangent space. - Added
mjv_connector
which has identical functionality tomjv_makeConnector
, but with more convenient "from-to" argument parametrization.mjv_makeConnector
is now deprecated. - Bumped oldest supported MacOS from version 10.12 to 11. MacOS 11 is the oldest version still maintained by Apple.
- The
passive viewer<PyViewerPassive>
handle now exposesupdate_hfield
,update_mesh
, andupdate_texture
methods to allow users to update renderable assets. (#812, #958, #965) - Allow a custom keyboard event callback to be specified in the
passive viewer<PyViewerPassive>
. (#766) - Fix GLFW crash when Python exits while the passive viewer is running. (#790)
- Added simple car example model.
Note
MuJoCo 2.3.6 is the last version to officially support Python 3.7.
ZppeDArq6AU
- Added 3x3x3 cube example model. See README for details.
- Fixed a bug that was causing an incorrect computation of the mesh bounding box and coordinate frame if the volume was invalid. In such case, now MuJoCo only accepts a non-watertight geometry if
shellinertia<body-geom-shellinertia>
is equal totrue
. - Fixed the sparse Jacobian multiplication logic that is used to compute derivatives for tendon damping and fluid force, which affects the behaviour of the
implicit and implicitfast integrators<geIntegration>
. - Fixes to
mj_ray
, in line with geom visualisation conventions:- Planes and height-fields respect the
geom_group
andflg_static
arguments. Before this change, rays would intersect planes and height-fields unconditionally. flg_static
now applies to all static geoms, not just those which are direct children of the world body.
- Planes and height-fields respect the
hqIMTNGaLF4
- Added touch-grid sensor plugin. See documentation for details, and associated touch_grid.xml example model. The plugin includes in-scene visualisation.
mXVPbppGk5I
- Added Visualization tab to simulate UI, corresponding to elements of the
visual<visual>
MJCF element. After modifying values in the GUI, a saved XML will contain the new values. The modifyable members ofmjStatistic
(extent<statistic-extent>
,meansize<statistic-meansize>
andcenter<statistic-center>
) are computed by the compiler and therefore do not have defaults. In order for these attributes to appear in the saved XML, a value must be specified in the loaded XML.
- Increased text width for UI elements in the default spacing. [before / after]:
- Added
mj_getState
andmj_setState
for getting and setting the simulation state as a concatenated vector of floating point numbers. See theState<geState>
section for details. - Added
mjContact.solreffriction<mjContact>
, allowing differentsolref<CSolver>
parameters for the normal and frictional axes of contacts when usingelliptic friction cones<option-cone>
. This attribute is required for elastic frictional collisions, see associated example model mimicking the spin-bounce recoil behaviour of elastic rubber balls. This is an advanced option currently only supported by explicitcontact pairs<contact-pair>
, using thesolreffriction<contact-pair-solreffriction>
attribute. - Added
mjd_inverseFD
for finite-differenced inverse-dynamics derivatives. - Added functions for operations on banded-then-dense "arrowhead" matrices. Such matrices are common when doing direct trajectory optimization. See
mju_cholFactorBand
documentation for details. - Added
mj_multiRay
function for intersecting multiple rays emanating from a single point. This is significantly faster than callingmj_ray
multiple times. - Ray-mesh collisions are now up to 10x faster, using a bounding volume hierarchy of mesh faces.
- Increased
mjMAXUIITEM
(maximum number of UI elements per section in Simulate) to 100. - Added
documentation<exProvider>
for resource providers. - Changed the formula for
mju_sigmoid
, a finite-support sigmoid s: R → [0, 1]. Previously, the smooth part consisted of two stitched quadratics, once continuously differentiable. It is now a single quintic, twice continuously differentiable:
$$\begin{aligned} s(x) = \begin{cases} 0, & & x \le 0 \\\ 6x^5 - 15x^4 + 10x^3, & 0 \lt & x \lt 1 \\\ 1, & 1 \le & x \qquad \end{cases} \end{aligned}$$
- Added optional
tausmooth<actuator-muscle-tausmooth>
attribute to muscle actuators. When positive, the time-constant τ of muscle activation/deactivation usesmju_sigmoid
to transition smoothly between the two extremal values given by the Millard et al. (2013) muscle model, within a range of width tausmooth. SeeMuscle actuators<CMuscle>
for more details. Relatedly,mju_muscleDynamics
now takes 3 parameters instead of 2, adding the new smoothing-width parameter. - Moved public C macro definitions out of mujoco.h into a new public header file called mjmacro.h. The new file is included by mujoco.h so this change does not break existing user code.
- Added instrumentation for the Address Sanitizer (ASAN) and Memory Sanitizer (MSAN) to detect memory bugs when allocating from the
mjData
stack and arena. - Removed
pstack
andparena
from the output ofmj_printData
, since these are implementation details of themjData
allocators that are affected by diagnostic paddings in instrumented builds. - Removed the
mj_activate
andmj_deactivate
functions. These had been kept around for compatibility with old user code from when MuJoCo was closed source, but have been no-op functions since open sourcing.
- Fix asset loading bug that prevented OBJ and PNG files from being read from disk when
mjVFS
is used. - Fix occasional segmentation faults on macOS when mouse perturbations are applied in the Python passive viewer.
- The
visualize
callback inmjpPlugin
now receives anmjvOption
as an input argument.
Note
This version is affected by an asset loading bug that prevents OBJ and PNG files from being read from disk when mjVFS
is used. Users are advised to skip to version 2.3.5 instead.
- Removed the "global" setting of the
compiler/coordinate<compiler-coordinate>
attribute. This rarely-used setting complicates the compiler logic and is blocking future improvements. In order to convert older models which used this option, load and save them in MuJoCo 2.3.3 or older.
- Added
visual-global<visual-global>
flagellipsoidinertia<visual-global-ellipsoidinertia>
to visualize equivalent body inertias with ellipsoids instead of the default boxes. - Added midphase and broadphase collision statistics to
mjData
. - Added documentation for
engine plugins<exPlugin>
. - Added struct information to the
introspect
module. - Added a new extension mechanism called
resource providers<exProvider>
. This extensible mechanism allows MuJoCo to read assets from data sources other than the local OS filesystem or theVirtual file system<Virtualfilesystem>
.
- Offscreen rendering on macOS is no longer restricted to the main thread. This is achieved by using the low-level Core OpenGL (CGL) API to create the OpenGL context, rather than going via GLFW which relies on Cocoa's NSOpenGL. The resulting context is not tied to a Cocoa window, and is therefore not tied to the main thread.
- Fixed a race condition in
viewer.launch_passive
andviewer.launch_repl
. These functions could previously return before an internal call tomj_forward
. This allows user code to continue and potentially modify physics state concurrently with the internalmj_forward
, resulting in e.g. MuJoCo stack overflow error or segmentation fault. - The
viewer.launch_passive
function now returns a handle which can be used to interact with the viewer. The passive viewer now also requires an explicit call tosync
on its handle to pick up any update to the physics state. This is to avoid race conditions that can result in visual artifacts. Seedocumentation<PyViewerPassive>
for details. - The
viewer.launch_repl
function has been removed since its functionality is superceded bylaunch_passive
. - Added a small number of missing struct fields discovered through the new
introspect
metadata.
- Fixed bug in the handling of ellipsoid-based fluid model forces in the new implicitfast integrator.
- Removed spurious whole-arena copying in mj_copyData, which can considerably slow down the copying operation.
- Make
shellinertia<body-geom-shellinertia>
ignoreexactmeshinertia<compiler-exactmeshinertia>
, which is only used for legacy volume computations (#759).
Improvements to implicit integration:
- The derivatives of the RNE algorithm are now computed using sparse math, leading to significant speed improvements for large models when using the
implicit integrator<geIntegration>
. - A new integrator called
implicitfast
was added. It is similar to the existing implicit integrator, but skips the derivatives of Coriolis and centripetal forces. See thenumerical integration<geIntegration>
section for a detailed motivation and discussion. The implicitfast integrator is recommended for all new models and will become the default integrator in a future version.
The table below shows the compute cost of the 627-DoF humanoid100 model using different integrators. "implicit (old)" uses dense RNE derivatives, "implicit (new)" is after the sparsification mentioned above. Timings were measured on a single core of an AMD 3995WX CPU.
- The derivatives of the RNE algorithm are now computed using sparse math, leading to significant speed improvements for large models when using the
timing | Euler | implicitfast | implicit (new) | implicit (old) |
---|---|---|---|---|
one step (ms) | 0.5 | 0.53 | 0.77 | 5.0 |
steps/second | 2000 | 1900 | 1300 | 200 |
- Added a collision mid-phase for pruning geoms in body pairs, see
documentation<coSelection>
for more details. This is based on static AABB bounding volume hierarchy (a BVH binary tree) in the body inertial frame. The GIF on the right is cut from this longer video. - The
mjd_transitionFD
function no longer triggers sensor calculation unless explicitly requested. - Corrected the spelling of the
inteval
attribute tointerval
in themjLROpt
struct. - Mesh texture and normal mappings are now 3-per-triangle rather than 1-per-vertex. Mesh vertices are no longer duplicated in order to circumvent this limitation as they previously were.
- The non-zeros for the sparse constraint Jacobian matrix are now precounted and used for matrix memory allocation. For instance, the constraint Jacobian matrix from the humanoid100 model, which previously required ~500,000
mjtNum
's, now only requires ~6000. Very large models can now load and run with the CG solver. - Modified
mju_error
andmju_warning
to be variadic functions (support for printf-like arguments). The functionsmju_error_i
,mju_error_s
,mju_warning_i
, andmju_warning_s
are now deprecated. - Implemented a performant
mju_sqrMatTDSparse
function that doesn't require dense memory allocation. - Added
mj_stackAllocInt
to get correct size for allocating ints on mjData stack. Reducing stack memory usage by 10% - 15%.
- Fixed IPython history corruption when using
viewer.launch_repl
. Thelaunch_repl
function now provides seamless continuation of an IPython interactive shell session, and is no longer considered experimental feature. - Added
viewer.launch_passive
which launches the interactive viewer in a passive, non-blocking mode. Calls tolaunch_passive
return immediately, allowing user code to continue execution, with the viewer automatically reflecting any changes to the physics state. (Note that this functionality is currently in experimental/beta stage, and is not yet described in ourviewer documentation<PyViewer>
.) - Added the
mjpython
launcher for macOS, which is required forviewer.launch_passive
to function there. - Removed
efc_
fields from joint indexers. Since the introduction of arena memory, these fields now have dynamic sizes that change between time steps depending on the number of active constraints, breaking strict correspondence between joints andefc_
rows. - Added a number of missing fields to the bindings of
mjVisual
andmjvPerturb
structs.
- Implemented a workaround for broken VSync on macOS so that the frame rate is correctly capped when the Vertical Sync toggle is enabled.
- Added optional labels to contact visualization, indicating which two geoms are contacting (names if defined, ids otherwise). This can be useful in cluttered scenes.
- A more performant mju_transposeSparse has been implemented that doesn't require dense memory allocation. For a constraint Jacobian matrix from the humanoid100.xml model, this function is 35% faster.
- The function
mj_name2id
is now implemented using a hash function instead of a linear search for better performance. - Geom names are now parsed from URDF. Any duplicate names are ignored.
mj_printData
output now contains contacting geom names.
- Fixed a bug that for
shellinertia
equal totrue
caused the mesh orientation to be overwritten by the principal components of the shell inertia, while the vertex coordinates are rotated using the volumetric inertia. Now the volumetric inertia orientation is used also in the shell case. - Fixed misalignment bug in mesh-to-primitive fitting when using the bounding box fitting option
fitaabb
.
- The
launch_repl
functionality in the Python viewer has been fixed. - Set
time
correctly inmjd_transitionFD
, to support time-dependent user code. - Fixed sensor data dimension validation when
user
type sensors are present. - Fixed incorrect plugin error message when a null
nsensordata
callback is encountered during model compilation. - Correctly end the timer (
TM_END
)mj_fwdConstraint
returns early. - Fixed an infinite loop in
mj_deleteFileVFS
.
- Increased precision of simulate sensor plot y-axis by 1 digit (#719).
- Body labels are now drawn at the body frame rather than inertial frame, unless inertia is being visualised.
- The
reset
callback now receives instance-specificplugin_state
andplugin_data
as arguments, rather than the entiremjData
. Sincereset
is called insidemj_resetData
before any physics forwarding call has been made, it is an error to read anything frommjData
at this stage. - The
capabilities
field inmjpPlugin
is renamedcapabilityflags
to more clearly indicate that this is a bit field.
- The
simulate
GUI is now available through themujoco
Python package asmujoco.viewer
. Seedocumentation<PyViewer>
for details. (Contribution by Levi Burner.) - The
Renderer
class from the MuJoCo tutorial Colab is now available directly in the native Python bindings.
The tendon
springlength
attribute can now take two values. Given two non-decreasing values, springlength specifies a deadband range for spring stiffness. If the tendon length is between the two values, the force is 0. If length is outside this range, the force behaves like a regular spring, with the spring resting length corresponding to the nearestspringlength
value. This can be used to create tendons whose limits are enforced by springs rather than constraints, which are cheaper and easier to analyse. See tendon_springlength.xml example model.Attention
This is a minor breaking API change.
mjModel.tendon_lengthspring
now has sizentendon x 2
rather thanntendon x 1
.-PJ6afdETUg
- Removed the requirement that stateless actuators come before stateful actuators.
- Added
mju_fill
,mju_symmetrize
andmju_eye
utility functions. - Added
gravcomp
attribute tobody<body>
, implementing gravity compensation and buoyancy. See balloons.xml example model. - Renamed the
cable
plugin library toelasticity
. - Added
actdim
attribute togeneral actuators<actuator-general>
. Values greater than 1 are only allowed for dyntypeuser
, as native activation dynamics are all scalar. Added example test implementing 2nd-order activation dynamics to engine_forward_test.cc. - Improved particle
composite<body-composite>
type, which now permits a user-specified geometry and multiple joints. See the two new examples: particle_free.xml and particle_free2d.xml. - Performance improvements for non-AVX configurations:
- 14% faster
mj_solveLD
using restrict. See engine_core_smooth_benchmark_test. - 50% faster
mju_dotSparse
using manual loop unroll. See engine_util_sparse_benchmark_test.
- 14% faster
Added new
solid
passive force plugin:AGcTGHbbze4
- This is new force field compatible with the
composite<body-composite>
particles. - Generates a tetrahedral mesh having particles with mass concentrated at vertices.
- Uses a piecewise-constant strain model equivalent to finite elements but expressed in a coordinate-free formulation. This implies that all quantities can be precomputed except edge elongation, as in a mass-spring model.
- Only suitable for small strains (large displacements but small deformations). Tetrahedra may invert if subject to large loads.
- This is new force field compatible with the
- Added API functions
mj_loadPluginLibrary
andmj_loadAllPluginLibraries
. The first function is identical todlopen
on a POSIX system, and toLoadLibraryA
on Windows. The second function scans a specified directory for all dynamic libraries file and loads each library found. Dynamic libraries opened by these functions are assumed to register one or more MuJoCo plugins on load. - Added an optional
visualize
callback to plugins, which is called duringmjv_updateScene
. This callback allows custom plugin visualizations. Enable stress visualization for the Cable plugin as an example. - Sensors of type
user<sensor-user>
no longer requireobjtype
,objname
andneedstage
. If unspecified, the objtype is nowmjOBJ_UNKNOWN<mjtObj>
.user
sensorsdatatype
default is now"real"
,needstage
default is now"acc"
. - Added support for capsules in URDF import.
- On macOS, issue an informative error message when run under Rosetta 2 translation on an Apple Silicon machine. Pre-built MuJoCo binaries make use of AVX instructions on x86-64 machines, which is not supported by Rosetta 2. (Before this version, users only get a cryptic "Illegal instruction" message.)
- Fixed bug in
mj_addFileVFS
that was causing the file path to be ignored (introduced in 2.1.4).
- Renamed the directory in which the
simulate
application searches for plugins fromplugin
tomujoco_plugin
. - Mouse force perturbations are now applied at the selection point rather than the body center of mass.
-
The
contact
array and arrays prefixed withefc_
inmjData
were moved out of thebuffer
into a newarena
memory space. These arrays are no longer allocated with fixed sizes whenmjData
is created. Instead, the exact memory requirement is determined during each call tomj_forward
(specifically, inmj_collision
andmj_makeConstraint
) and the arrays are allocated from thearena
space. Thestack
now also shares its available memory witharena
. This change reduces the memory footprint ofmjData
in models that do not use the PGS solver, and will allow for significant memory reductions in the future. See theMemory allocation <CSize>
section for details.RHnXD6uO3Mg
- Added colab notebook tutorial showing how to balance the humanoid on one leg with a Linear Quadratic Regulator. The notebook uses MuJoCo's native Python bindings, and includes a draft
Renderer
class, for easy rendering in Python. Try it yourself: - Updates to humanoid model:
- Added two keyframes (stand-on-one-leg and squat).
- Increased maximum hip flexion angle.
- Added hamstring tendons which couple the hip and knee at high hip flexion angles.
- General cosmetic improvements, including improved use of defaults and better naming scheme.
-
Added
mju_boxQP
and allocation functionmju_boxQPmalloc
for solving the box-constrained Quadratic Program:$$x^* = \text{argmin} \; \tfrac{1}{2} x^T H x + x^T g \quad \text{s.t.} \quad l \le x \le u$$ The algorithm, introduced in Tassa et al. 2014, converges after 2-5 Cholesky factorisations, independent of problem size.
- Added
mju_mulVecMatVec
to multiply a square matrix M with vectors x and y on both sides. The function returns xTMy. - Added new plugin API. Plugins allow developers to extend MuJoCo's capability without modifying core engine code. The plugin mechanism is intended to replace the existing callbacks, though these will remain for the time being as an option for simple use cases and backward compatibility. The new mechanism manages stateful plugins and supports multiple plugins from different sources, allowing MuJoCo extensions to be introduced in a modular fashion, rather than as global overrides. Note the new mechanism is currently undocumented except in code, as we test it internally. If you are interested in using the plugin mechanism, please get in touch first.
- Added
assetdir
compiler option, which sets the values of bothmeshdir
andtexturedir
. Values in the latter attributes take precedence overassetdir
. - Added
realtime
option tovisual<visual>
for starting a simulation at a slower speed. - Added new
cable
composite type:- Cable elements are connected with ball joints.
- The initial parameter specifies the joint at the starting boundary:
free
,ball
, ornone
. - The boundary bodies are exposed with the names
B_last
andB_first
. - The vertex initial positions can be specified directly in the XML with the parameter
vertex
. - The orientation of the body frame is the orientation of the material frame of the curve.
-
Added new
cable
passive force plugin:- Twist and bending stiffness can be set separately with the parameters
twist
andbend
. - The stress-free configuration can be set to be the initial one or flat with the flag
flat
. - New cable.xml example showing the formation of plectoneme.
- New coil.xml example showing a curved equilibrium configuration.
- New belt.xml example showing interaction between twist and anisotropy.
- Added test using cantilever exact solution.
25kQP671fJE
4DvGe-BodFU
QcGdpUd5H0c
- Twist and bending stiffness can be set separately with the parameters
- Added
id
andname
properties to named accessor objects. These provide more Pythonic API access tomj_name2id
andmj_id2name
respectively. - The length of
MjData.contact
is nowncon
rather thannconmax
, allowing it to be straightforwardly used as an iterator without needing to checkncon
. - Fix a memory leak when a Python callable is installed as callback (#527).
BcHZ5BFeTmU
- Added
adhesion actuators<actuator-adhesion>
mimicking vacuum grippers and adhesive biomechanical appendages. - Added related example model and video:
- Added
mj_jacSubtreeCom
for computing the translational Jacobian of the center-of-mass of a subtree. - Added
torquescale
andanchor
attributes toweld
constraints.torquescale
sets the torque-to-force ratio exerted by the constraint,anchor
sets the point at which the weld wrench is applied. Seeweld <equality-weld>
for more details. - Increased
mjNEQDATA
, the row length of equality constraint parameters inmjModel.eq_data
, from 7 to 11. - Added visualisation of anchor points for both
connect
andweld
constraints (activated by the 'N' key insimulate
). Added weld.xml showing different uses of new weld attributes.
s-0JHanqV1A
- Cartesian 6D end-effector control is now possible by adding a reference site to actuators with
site
transmission. See description of newrefsite
attribute in theactuator<actuator-general>
documentation and refsite.xml example model. Added
autolimits
compiler option. Iftrue
, joint and tendonlimited
attributes and actuatorctrllimited
,forcelimited
andactlimited
attributes will automatically be set totrue
if the corresponding range is defined andfalse
otherwise.If
autolimits="false"
(the default) models where arange
attribute is specified without thelimited
attribute will fail to compile. A future release will change the default ofautolimits
totrue
, and this compilation error allows users to catch this future change of behavior.Attention
This is a breaking change. In models where a range was defined but
limited
was unspecified, explicitly set limited tofalse
or remove the range to maintain the current behavior of your model.- Added moment of inertia computation for all well-formed meshes. This option is activated by setting the compiler flag
exactmeshinertia
totrue
(defaults tofalse
). This default may change in the future. - Added parameter
shellinertia
togeom
, for locating the inferred inertia on the boundary (shell). Currently only meshes are supported. For meshes from which volumetric inertia is inferred, raise error if the orientation of mesh faces is not consistent. If this occurs, fix the mesh in e.g., MeshLab or Blender.
I2q7D0Vda-A
- Added catenary visualisation for hanging tendons. The model seen in the video can be found here.
- Added
azimuth
andelevation
attributes tovisual/global<visual-global>
, defining the initial orientation of the free camera at model load time. - Added
mjv_defaultFreeCamera
which sets the default free camera, respecting the above attributes. simulate
now supports taking a screenshot via a button in the File section or viaCtrl-P
.- Improvements to time synchronisation in simulate, in particular report actual real-time factor if different from requested factor (if e.g., the timestep is so small that simulation cannot keep up with real-time).
- Added a disable flag for sensors.
mju_mulQuat
andmju_mulQuatAxis
support in place computation. For examplemju_mulQuat(a, a, b);
sets the quaterniona
equal to the product ofa
andb
.- Added sensor matrices to
mjd_transitionFD
(note this is an API change).
- Removed
distance
constraints.
- Fixed rendering of some transparent geoms in reflection.
- Fixed
intvelocity
defaults parsing.
- Added
mjd_transitionFD
to compute efficient finite difference approximations of the state-transition and control-transition matrices,see here<derivatives>
for more details. - Added derivatives for the ellipsoid fluid model.
- Added
ctrl
attribute tokeyframes<keyframe>
. - Added
clock
sensor whichmeasures time<sensor-clock>
. - Added visualisation groups to skins.
- Added actuator visualisation for
free
andball
joints and for actuators withsite
transmission. - Added visualisation for actuator activations.
- Added
<actuator-intvelocity>
actuator shortcut for "integrated velocity" actuators, documentedhere <actuator-intvelocity>
. - Added
<actuator-damper>
actuator shortcut for active-damping actuators, documentedhere <actuator-damper>
. mju_rotVecMat
andmju_rotVecMatT
now support in-place multiplication.mjData.ctrl
values are no longer clamped in-place, remain untouched by the engine.- Arrays in mjData's buffer now align to 64-byte boundaries rather than 8-byte.
- Added memory poisoning when building with Address Sanitizer (ASAN) and Memory Sanitizer (MSAN). This allows ASAN to detect reads and writes to regions in
mjModel.buffer
andmjData.buffer
that do not lie within an array, and for MSAN to detect reads from uninitialised fields inmjData
followingmj_resetData
. - Added a slider-crank example model.
Activation clamping <CActRange>
was not being applied in theimplicit integrator<geIntegration>
.- Stricter parsing of orientation specifiers. Before this change, a specification that included both
quat
and analternative specifier<COrientation>
e.g.,<geom ... quat=".1 .2 .3 .4" euler="10 20 30">
, would lead to thequat
being ignored and onlyeuler
being used. After this change a parse error will be thrown. - Stricter parsing of XML attributes. Before this change an erroneous XML snippet like
<geom size="1/2 3 4">
would have been parsed assize="1 0 0"
and no error would have been thrown. Now throws an error. - Trying to load a
NaN
via XML like<geom size="1 NaN 4">
, while allowed for debugging purposes, will now print a warning. - Fixed null pointer dereference in
mj_loadModel
. - Fixed memory leaks when loading an invalid model from MJB.
- Integer overflows are now avoided when computing
mjModel
buffer sizes. - Added missing warning string for
mjWARN_BADCTRL
.
- Changed MacOS packaging so that the copy of
mujoco.framework
embedded inMuJoCo.app
can be used to build applications externally.
MuJoCo is now fully open-source software. Newly available top level directories are:
a.
src/
: All source files. Subdirectories correspond to the modules described in the Programming chapterintroduction<inIntro>
:src/engine/
: Core engine.src/xml/
: XML parser.src/user/
: Model compiler.src/visualize/
: Abstract visualizer.src/ui/
: UI framework.
test/
: Tests and corresponding asset files.dist/
: Files related to packaging and binary distribution.
- Added contributor's guide and style guide.
- Added analytic derivatives of smooth (unconstrained) dynamics forces, with respect to velocities:
- Centripetal and Coriolis forces computed by the Recursive Newton-Euler algorithm.
- Damping and fluid-drag passive forces.
- Actuation forces.
- Added
implicit
integrator. Using the analytic derivatives above, a new implicit-in-velocity integrator was added. This integrator lies between the Euler and Runge Kutta integrators in terms of both stability and computational cost. It is most useful for models which use fluid drag (e.g. for flying or swimming) and for models which usevelocity actuators<actuator-velocity>
. For more details, see theNumerical Integration<geIntegration>
section. - Added
actlimited
andactrange
attributes togeneral actuators<actuator-general>
, for clamping actuator internal states (activations). This clamping is useful for integrated-velocity actuators, see theActivation clamping <CActRange>
section for details. mjData
fieldsqfrc_unc
(unconstrained forces) andqacc_unc
(unconstrained accelerations) were renamedqfrc_smooth
andqacc_smooth
, respectively. While "unconstrained" is precise, "smooth" is more intelligible than "unc".- Public headers have been moved from
/include
to/include/mujoco/
, in line with the directory layout common in other open source projects. Developers are encouraged to include MuJoCo public headers in their own codebase via#include <mujoco/filename.h>
. - The default shadow resolution specified by the
shadowsize<visual-quality>
attribute was increased from 1024 to 4096. - Saved XMLs now use 2-space indents.
- Antialiasing was disabled for segmentation rendering. Before this change, if the
offsamples<visual-quality>
attribute was greater than 0 (the default value is 4), pixels that overlapped with multiple geoms would receive averaged segmentation IDs, leading to incorrect or non-existent IDs. After this changeoffsamples
is ignored during segmentation rendering. - The value of the enable flag for the experimental multiCCD feature was made sequential with other enable flags. Sequentiality is assumed in the
simulate
UI and elsewhere. - Fix issue of duplicated meshes when saving models with OBJ meshes using mj_saveLastXML.
- Added an experimental feature: multi-contact convex collision detection, activated by an enable flag. See full description
here <option-flag>
.
- GLAD initialization logic on Linux now calls
dlopen
to load a GL platform dynamic library if a*GetProcAddress
function is not already present in the process' global symbol table. In particular, processes that use GLFW to set up a rendering context that are not explicitly linked againstlibGLX.so
(this applies to the Python interpreter, for example) will now work correctly rather than fail with agladLoadGL
error whenmjr_makeContext
is called. - In the Python bindings, named indexers for scalar fields (e.g. the
ctrl
field for actuators) now return a NumPy array of shape(1,)
rather than()
. This allows values to be assigned to these fields more straightforwardly.
- MuJoCo now uses GLAD to manage OpenGL API access instead of GLEW. On Linux, there is no longer a need to link against different GL wrangling libraries depending on whether GLX, EGL, or OSMesa is being used. Instead, users can simply use GLX, EGL, or OSMesa to create a GL context and
mjr_makeContext
will detect which one is being used. - Added visualisation for contact frames. This is useful when writing or modifying collision functions, when the actual direction of the x and y axes of a contact can be important.
- The
_nogl
dynamic library is no longer provided on Linux and Windows. The switch to GLAD allows us to resolve OpenGL symbols whenmjr_makeContext
is called rather than when the library is loaded. As a result, the MuJoCo library no longer has an explicit dynamic dependency on OpenGL, and can be used on system where OpenGL is not present.
- Fixed a bug in simulate where pressing '[' or ']' when a model is not loaded causes a crash.
- Contact frame visualisation was added to the Simulate GUI.
- Renamed "set key", "reset to key" to "save key" and "load key", respectively.
- Changed bindings of F6 and F7 from the not very useful "vertical sync" and "busy wait" to the more useful cycling of frames and labels.
mj_resetData
zeroes out thesolver_nnz
field.- Removed a special branch in
mju_quat2mat
for unit quaternions. Previously,mju_quat2mat
skipped all computation if the real part of the quaternion equals 1.0. For very small angles (e.g. when finite differencing), the cosine can evaluate to exactly 1.0 at double precision while the sine is still nonzero.
simulate
now supports cycling through cameras (with the[
and]
keys).mjVIS_STATIC
toggles all static bodies, not just direct children of the world.
- Added a
free()
method toMjrContext
. - Enums now support arithmetic and bitwise operations with numbers.
- Fixed rendering bug for planes, introduced in 2.1.2. This broke maze environments in dm_control.
- Added new
Python bindings<python>
, which can be installed viapip install mujoco
, and imported asimport mujoco
. - Added new
Unity plug-in<unity>
. - Added a new
introspect
module, which provides reflection-like capability for MuJoCo's public API, currently describing functions and enums. While implemented in Python, this module is expected to be generally useful for automatic code generation targeting multiple languages. (This is not shipped as part of themujoco
Python bindings package.)
- Moved definition of
mjtNum
floating point type into a new header mjtnum.h. - Renamed header mujoco_export.h to
mjexport.h<inHeader>
. - Added
mj_printFormattedData
, which accepts a format string for floating point numbers, for example to increase precision.
- MuJoCo can load OBJ mesh files.
- Meshes containing polygons with more than 4 vertices are not supported.
- In OBJ files containing multiple object groups, any groups after the first one will be ignored.
Added (post-release, not included in the 2.1.2 archive) textured mug example model:
- Added optional frame-of-reference specification to
framepos<sensor-framepos>
,framequat<sensor-framequat>
,framexaxis<sensor-framexaxis>
,frameyaxis<sensor-frameyaxis>
,framezaxis<sensor-framezaxis>
,framelinvel<sensor-framelinvel>
, andframeangvel<sensor-frameangvel>
sensors. The frame-of-reference is specified by newreftype
andrefname
attributes. - Sizes of
user parameters <CUser>
are now automatically inferred.- Declarations of user parameters in the top-level
size <size>
clause (e.g.nuser_body
,nuser_jnt
, etc.) now accept a value of -1, which is the default. This will automatically set the value to the length of the maximum associateduser
attribute defined in the model. - Setting a value smaller than -1 will lead to a compiler error (previously a segfault).
- Setting a value to a length smaller than some
user
attribute defined in the model will lead to an error (previously additional values were ignored).
- Declarations of user parameters in the top-level
- Increased the maximum number of lights in an
mjvScene
from 8 to 100. - Saved XML files only contain explicit
inertial <body-inertial>
elements if the original XML included them. Inertias that were automatically inferred by the compiler'sinertiafromgeom <compiler>
mechanism remain unspecified. - User-selected geoms are always rendered as opaque. This is useful in interactive visualizers.
- Static geoms now respect their
geom group<body-geom>
for visualisation. Until this change rendering of static geoms could only be toggled using themjVIS_STATIC<mjtVisFlag>
visualisation flag . After this change, both the geom group and the visualisation flag need to be enabled for the geom to be rendered. - Pointer parameters in function declarations in
mujoco.h<inHeader>
that are supposed to represent fixed-length arrays are now spelled as arrays with extents, e.g.mjtNum quat[4]
rather thanmjtNum* quat
. From the perspective of C and C++, this is a non-change since array types in function signatures decay to pointer types. However, it allows autogenerated code to be aware of expected input shapes. - Experimental stateless fluid interaction model. As described
here <gePassive>
, fluid forces use sizes computed from body inertia. While sometimes convenient, this is very rarely a good approximation. In the new model forces act on geoms, rather than bodies, and have a several user-settable parameters. The model is activated by setting a new attribute:<geom fluidshape="ellipsoid"/>
. The parameters are described succinctlyhere<body-geom>
, but we leave a full description or the model and its parameters to when this feature leaves experimental status.
mj_loadXML
andmj_saveLastXML
are now locale-independent. The Unity plugin should now work correctly for users whose system locales use commas as decimal separators.- XML assets in VFS no longer need to end in a null character. Instead, the file size is determined by the size parameter of the corresponding VFS entry.
- Fix a vertex buffer object memory leak in
mjrContext
when skins are used. - Camera quaternions are now normalized during XML compilation.
- Windows binaries are now built with Clang.
- Added
mj_printFormattedModel
, which accepts a format string for floating point numbers, for example to increase precision. - Added
mj_versionString
, which returns human-readable string that represents the version of the MuJoCo binary. Converted leading underscores to trailing underscores in private instances of API struct definitions, to conform to reserved identifier directive, see C standard: Section 7.1.3.
Attention
This is a minor breaking change. Code which references private instances will break. To fix, replace leading underscores with trailing underscores, e.g.
_mjModel
mjModel_
.
- Safer string handling: replaced
strcat
,strcpy
, andsprintf
withstrncat
,strncpy
, andsnprintf
respectively. - Changed indentation from 4 spaces to 2 spaces, K&R bracing style, added braces to one-line conditionals.
- Fixed reading from uninitialized memory in PGS solver.
Computed capsule inertias are now exact. Until this change, capsule masses and inertias computed by the
compiler <compiler>
'sinertiafromgeom
mechanism were approximated by a cylinder, formed by the capsule's cylindrical middle section, extended on both ends by half the capsule radius. Capsule inertias are now computed with the Parallel Axis theorem, applied to the two hemispherical end-caps.Attention
This is a minor breaking change. Simulation of a model with automatically-computed capsule inertias will be numerically different, leading to, for example, breakage of golden-value tests.
Fixed bug related to
force <sensor-force>
andtorque <sensor-torque>
sensors. Until this change, forces and torques reported by F/T sensors ignored out-of-tree constraint wrenches except those produced by contacts. Force and torque sensors now correctly take into account the effects ofconnect <equality-connect>
andweld <equality-weld>
constraints.Note
Forces generated by
spatial tendons <tendon-spatial>
which are outside the kinematic tree (i.e., between bodies which have no ancestral relationship) are still not taken into account by force and torque sensors. This remains a future work item.
testspeed
: Added injection of pseudo-random control noise, turned on by default. This is to avoid settling into some fixed contact configuration and providing an unrealistic timing measure.simulate
:- Added slower-than-real-time functionality, which is controlled via the '+' and '-' keys.
- Added sliders for injecting Brownian noise into the controls.
- Added "Print Camera" button to print an MJCF clause with the pose of the current camera.
- The camera pose is not reset when reloading the same model file.
TinyXML
was replaced withTinyXML2
6.2.0.qhull
was upgraded to version 8.0.2.libCCD
was upgraded to version 1.4.- On Linux,
libstdc++
was replaced withlibc++
.
- MacOS packaging. We now ship Universal binaries that natively support both Apple Silicon and Intel CPUs.
- MuJoCo library is now packaged as a Framework Bundle <https://developer.apple.com/library/archive/documentation/MacOSX/Conceptual/BPFrameworks/Concepts/FrameworkAnato my.html>, allowing it to be incorporated more easily into Xcode projects (including Swift projects). Developers are encouraged to compile and link against MuJoCo using the
-framework mujoco
flag, however all header files and thelibmujoco.2.1.1.dylib
library can still be directly accessed inside the framework. - Sample applications are now packaged into an Application Bundle called
MuJoCo.app
. When launched via GUI, the bundle launches thesimulate
executable. Other precompiled sample programs are shipped inside that bundle (inMuJoCo.app/Contents/MacOS
) and can be launched via command line. - Binaries are now signed and the disk image is notarized.
- MuJoCo library is now packaged as a Framework Bundle <https://developer.apple.com/library/archive/documentation/MacOSX/Conceptual/BPFrameworks/Concepts/FrameworkAnato my.html>, allowing it to be incorporated more easily into Xcode projects (including Swift projects). Developers are encouraged to compile and link against MuJoCo using the
- Windows binaries and libraries are now signed.
- Link-time optimization is enabled on Linux and macOS, leading to an average of ~20% speedup when benchmarked on three test models (
cloth.xml
,humanoid.xml
, andhumanoid100.xml
). - Linux binaries are now built with LLVM/Clang instead of GCC.
- An AArch64 (aka ARM64) Linux build is also provided.
- Private symbols are no longer stripped from shared libraries on Linux and MacOS.
- Clean-up of the
model/
directory.- Rearranged into subdirectories which include all dependencies.
- Added descriptions in XML comments, cleaned up XMLs.
- Deleted some composite models:
grid1
,grid1pin
,grid2
,softcylinder
,softellipsoid
.
- Added descriptive animations in
docs/images/models/
:
- Keyframes now have
mocap_pos
andmocap_quat
fields (mpos and quat attributes in the XML) allowing mocap poses to be stored in keyframes. - New utility functions:
mju_insertionSortInt
(integer insertion sort) andmju_sigmoid
(constructing a sigmoid from two half-quadratics).
- The preallocated sizes in the virtual file system (VFS) increased to 2000 and 1000, to allow for larger projects.
- The C structs in the
mjuiItem
union are now named, for compatibility. - Fixed:
mjcb_contactfilter
type ismjfConFilt
(wasmjfGeneric
). - Fixed: The array of sensors in
mjCModel
was not cleared. - Cleaned up cross-platform code (internal changes, not visible via the API).
- Fixed a bug in parsing of XML
texcoord
data (related to number of vertices). - Fixed a bug in simulate.cc related to
nkey
(the number of keyframes). - Accelerated collision detection in the presence of large numbers of non-colliding geoms (with
contype==0 and conaffinity==0
).
- Figure selection type changed from
int
tofloat
. - Figures now show data coordinates, when selection and highlight are enabled.
- Changed
mjMAXUIMULTI
to 35,mjMAXUITEXT
to 300,mjMAXUIRECT
to 25. - Added collapsable sub-sections, implemented as separators with state:
mjSEPCLOSED
collapsed,mjSEPCLOSED+1
expanded. - Added
mjITEM_RADIOLINE
item type. - Added function
mjui_addToSection
to simplify UI section construction. - Added subplot titles to
mjvFigure
.
render_gl2
guards against non-finite floating point data in the axis range computation.render_gl2
draws lines from back to front for better visibility.- Added function
mjr_label
(for text labels). mjr_render
exits immediately ifngeom==0
, to avoid errors from uninitialized scenes (e.g.frustrum==0
).- Added scissor box in
mjr_render
, so we don't clear the entire window at every frame.
- Removed the entire license manager. The functions
mj_activate
andmj_deactivate
are still there for backward compatibility, but now they do nothing and it is no longer necessary to call them. - Removed the remote license certificate functions
mj_certXXX
.
For changelogs of earlier versions please see roboti.us.