https://youtu.be/17XpwnqyCXs
New transmission type mjTRN_SO3: a relative orientation, targeting a ball
joint or a site+refsite pair. It is the first transmission with more than
one force output: its length is the norm of the expmap vector of the
relative rotation and its moment axes are the 3 rows of the
relative rotational Jacobian, without projecting onto per-actuator gears.
New force law mjGAIN_SO3/mjBIAS_SO3: a geodesic PD servo, force =
kp * log(q_current^-1 * q_target) - kv * velocity, exact for arbitrary axis
combinations with a unique equilibrium at every commanded orientation.
Error, moment rows and velocity all live in the child frame (joint or
site): the right-difference error is the gradient of the geodesic
potential in that frame. The parent-frame (left) error is not: driving
child-frame torques with it pumps energy at large angles, settling into
steady-spinning limit cycles (the SO3LargeAngleConvergence test). The
integrator variant stores the 3D orientation setpoint in act (actnum = 3,
re-anchored to a bounded representative at integration time). Exposed in
MJCF as <orientation joint=|site=+refsite= kp kv|dampratio>, or via
<general gaintype="so3" biastype="so3">.
The setpoint input has two charts: an expmap target (3 controls, default)
or a quaternion target (4 controls) -- <orientation input="quat">, the
first actuator with different input and output widths. The signature is
recorded in a new per-actuator field actuator_ctrlspec (mjtCtrlChart),
whose meaning is scoped by the gain type the way gain/bias parameters are;
ctrlnum is derived from it at compile time and remains the layout
authority. An explicit field rather than width inference or a prm slot:
width-as-chart cannot express same-width signatures (upcoming servo input
subsets), and prm slots are the input_mode pattern this stack retires.
The force law normalizes the commanded quaternion, making it scale- and
antipodally-invariant. The all-zero ctrl still maps to the identity via
mju_normalize4, but it is a degenerate point (a nudge of any component
commands a half-turn), so quat inputs reset to the identity quaternion:
new mj_resetCtrl sets neutral ctrl values (zero, except qw = 1), called
by mj_resetData and the viewers' Clear All. The quat chart is
restricted to dyntype 'none': integrating a quaternion setpoint linearly
is not meaningful on the manifold. New mjsActuator.ctrlspec field carries
the signature through the spec and XML round-trip.
Actuator sensors (actuatorpos/vel/frc) now report one value per force
output; dim = 3 on an SO3 actuator.
As the first actuator with nu != nactuator, this commit also makes the
viewers multi-input aware: the control sliders in simulate and studio,
which indexed per-actuator arrays by control index (out of bounds on
this model class), are generated per control and labeled with the
actuator name plus an input suffix ("orient/qw"), via the new
introspection helper mj_actuatorInputName -- the single source of truth
for input names, extended by each new multi-input type (quaternion
components are w-first: qw, qx, qy, qz). Slider ranges now honor a
defined ctrlrange even when ctrllimited is false: range is the UI hint,
limited is the clamp -- wrapped and expmap setpoints are unbounded but
still want finite sliders, while quat components are truly bounded.
The rotational demo model is orientation.xml under
test/engine/testdata/actuation/, upgraded to a three-way contrast:
per-axis wrapped servos vs an expmap-commanded vs a quat-commanded
orientation actuator, on identical checker-textured boxes. It is loaded
by the mixed-axis contrast and input-name tests, and doubles as the
viewer test model (slider groups of 3 independent, 3 grouped, 4 grouped).
PiperOrigin-RevId: 951607063
Change-Id: If235dba8e2f2ca72672e7c62531a27e967c6a373
https://youtu.be/GioWwB36XHI
The new geom attribute adhesion (units of force, signed; pair-level
override) translates the contact friction cone along its normal so
that the force origin lies strictly inside it. Consequences: each
contact can pull with up to the given force before breaking, and the
tangential friction budget becomes mu*(f_N + adhesion) -- the
Mohr-Coulomb yield condition with cohesion c = mu*adhesion -- so
lightly-squeezed grasps retain a guaranteed friction floor.
A translated cone factors exactly into {constant attractive force}
+ {original cone}, so no solver kernels change. The implementation is
this factorization: a constant attraction along contact normals
accumulated into the new mjData.qfrc_adhesion (summed into
qfrc_passive), plus a bias of adhesive contact rows' reference
acceleration (aref += R*adhesion), which makes resting penetration
exactly independent of adhesion. Contacts of adhesive pairs remain
active throughout the gap zone, producing rows with positive violation
whose reference acceleration pulls: a tether that resists pull-off
smoothly, captures objects released within the band into steady
contact, and detaches at the specified force. Adhesion values of the
two geoms combine by sum; explicit pairs override.
mj_contactForce reports the net interface force (cone force minus the
adhesive pull), whose normal component can now be negative. Negative
adhesion is allowed and produces a repulsive offset (air hockey).
PiperOrigin-RevId: 950858148
Change-Id: I879c08eba7ae501e5c0f8c2f807167344da4c2bc
- Wrapping in force path is local; act is re-anchored at integration time.
- Remove hardcoded `actrange` for intvelocity actuators.
PiperOrigin-RevId: 949566477
Change-Id: I349fdf17eedfbb2174d698cc1a6a91d52810b4a3
https://www.youtube.com/watch?v=PdSdrqhSiZA
The new geom attribute surfacevel (6 numbers: linear and angular velocity in the geom's local frame, angular about the geom frame origin) specifies the velocity of the geom's surface material relative to the geom frame. The relative surface velocity of the two geoms is added to the tangential contact rows of efc_vel in mj_referenceConstraint, so friction drives touching bodies toward the motion of the surface: objects on a conveyor are transported at belt speed, turntables impart omega x r with torsional spin-up for condim >= 4, and surface velocities compose with each other and with body motion. The component along the contact normal is projected out: probe experiments showed that velocity-space emission chatters mass-independently and ingestion merely deepens penetration; normal-direction effects belong to force-space features.
surfacevel is interpreted in the geom frame as authored: for mesh geoms, whose compiled frame absorbs the mesh centering and principal-axes transform, the compiler re-expresses the authored value in the compiled frame.
No special interaction with sleeping: objects being transported do not fall asleep because they are moving; objects at rest on an active surface may sleep like any other resting object.
Includes showcase models (model/surfacevel/): a luggage carousel whose ring is a spinning square-profile supertorus fed by a cascade of belts with matched spinning end rollers, bags dropping in and circulating indefinitely; and a treadmill with a passive humanoid.
PiperOrigin-RevId: 948647785
Change-Id: I0c6559a91cc7ece1237eb8ac2e51986e7342d962
Extend mjpResourceProvider with an optional write callback (write)
so that mj_encode, mj_saveXML, and mj_saveModel can write to any
registered provider.
PiperOrigin-RevId: 945202741
Change-Id: I37903425260932e555f4a8c2392c4ff8c2e6cc06
On Windows, std::filesystem::path::string() returns backslashes while
zip entries use forward slashes. This caused lookup mismatches making
MJZ decoding fail on Windows with 'could not decode content'.
Use generic_string() (which always returns forward slashes) for all
path operations used in zip entry lookups, and normalize the archive
name at construction time.
PiperOrigin-RevId: 943538265
Change-Id: I50cafff82fd7f5f315ccfc890f660e138e4448a2
Undo mistaken auto-format of the schema table, revert it to be more human-readable.
PiperOrigin-RevId: 941628625
Change-Id: Ifc51996da9a7df9d1a03392a0ade256fb8b1c151
The `<attach>` element now supports a "frame" attribute, allowing users to specify either a "body" or a "frame" to attach to, but not both. The XML parser has been updated to handle this new attribute and the mutual exclusivity constraint.
PiperOrigin-RevId: 941245904
Change-Id: I4c0edeed5f3a9e456aed96c373b1647fe79841d9
For example when loading parent_merge.xml:
```
WARNING: Attach conflict when attaching 'child' to 'parent_merge', policy is 'merge'
timestep: parent has 0.005, child has 0.002, taking the minimum
iterations: parent has 50, child has 100, taking the maximum
flag 'Damper': added from child
```
When loading parent_error.xml:
```
XML Error: Attach conflict when attaching 'child' to 'parent_error', policy is 'error'
timestep: parent has 0.005, child has 0.002
iterations: parent has 50, child has 100
Element 'attach', line 10
```
PiperOrigin-RevId: 933620810
Change-Id: Ib477863b5ef763474d27fb4be5a4148be1d5d500
Compiler warnings are now accumulated in a vector of strings within the mjSpec object. New API functions `mjs_numWarnings` and `mjs_getWarning` are added to access these warnings. The compiler's log handler now chains warnings to the global log handler, ensuring they are still displayed immediately. Call sites in `mj_loadXML`, `mj_compile`, and the Python and WASM bindings have been updated to use the new warning API.
PiperOrigin-RevId: 933361650
Change-Id: I47cab98a460c57b0898c0a1a43fce2a5b9648eb1
--
3439d8a5cd745dfd2776593916eead65cb456afc by Kevin Zakka <kevinarmandzakka@gmail.com>:
Respect an explicit CMAKE_INTERPROCEDURAL_OPTIMIZATION=OFF
The default-LTO guard checked the value rather than whether it was DEFINED, so an
explicit -DCMAKE_INTERPROCEDURAL_OPTIMIZATION=OFF (used in CI to cut build time)
was silently flipped back ON. Check DEFINED instead; default-on for Release is
preserved when the caller makes no choice.
--
bd15d1b264e5ab9594669b58fa1e0388d0a16f6b by Kevin Zakka <kevinarmandzakka@gmail.com>:
Speed up CI
~10x faster on the POSIX jobs (~45m -> ~4-5m) and ~2x overall wall-clock.
- Build Studio/Filament and WASM only in their dedicated canary jobs, not in
every matrix job (WASM uses emcc, which ignores the host compiler).
- Compiler matrix -> build_matrix.json with core/extended tiers: PRs build the
core set, pushes to main run the full sweep.
- ccache across build jobs (studio cache keyed on the Filament pin); fix the
Python-bindings build so ccache hits (CCACHE_BASEDIR).
- Disable IPO/LTO on POSIX (it was silently on); keep it on Windows where /GL-off
exposes a latent test bug and build time is not the bottleneck.
- Run ctest in parallel on POSIX (~2x); uv for Python installs (~29s -> ~8s).
- Move MJX (compiler-independent) to a single dedicated job.
- Restrict GITHUB_TOKEN to contents: read; bump actions off deprecated Node20.
--
c0618ab7aef524b238e0a30f2f23c50c4ce0c9b1 by Kevin Zakka <kevinarmandzakka@gmail.com>:
Build the gcc jobs with LTO off too
Restores LTO-off for gcc (recovering the build-time win). That surfaces known
gcc-12 -Wrestrict false positives in libstdc++ <char_traits> at -O3; two clean,
behavior-preserving rewrites in the XML writer avoid them. Confirmed gcc-12 and
gcc-14 build clean with LTO off (PR #3325).
--
2c38da0f48f77635e58e4b7931b86d60f3c253c7 by Kevin Zakka <kevinarmandzakka@gmail.com>:
Respect explicit IPO=OFF in the Simulate and Sample options too
Apply the same DEFINED check as cmake/MujocoOptions.cmake to the simulate/ and
sample/ subprojects (which carry identical copies of the guard) to keep the three
in sync, as the internal import requires. Since the guard now honors =OFF, stop
forcing IPO=OFF on the tiny samples/simulate CI builds so they keep their default
LTO and don't expose the gcc -Werror false positives that -O3-without-LTO triggers.
COPYBARA_INTEGRATE_REVIEW=https://github.com/google-deepmind/mujoco/pull/3315 from google-deepmind:speed-up-ci 2c38da0f48f77635e58e4b7931b86d60f3c253c7
PiperOrigin-RevId: 930008698
Change-Id: Ic41dc87881833c95f2ebfc0602de1ed438db3d4f
The function called tinyxml2's LoadFile directly, which only works on
the OS file system. Reading through mju_openResource lets it work
against any registered backend (VFS, HTTP, github:, ...).
Since the mjz format is just an archive for MJCF assets this seems like a sensible place. The upcoming mjz encoder will also need to make use of the full precision XML utility that is local to src/xml.
PiperOrigin-RevId: 912044746
Change-Id: I6a9fef24b1c3fec5b5edc3a8d4c8e22584273264
This change adds a new passive force computation for flexes with elastic2d="bend" and dof="trilinear". The bending energy is based on the squared difference of normals between adjacent face elements at their shared edge midpoint. The edge data is precomputed during model compilation and stored in flex_bending.
PiperOrigin-RevId: 910772638
Change-Id: I3b12c7b7f1ba6ac1875df495d89e8cfec921ca80
Each mjEQ_FLEXSTRAIN equality now represents a single cell within a flex. This allows for more efficient sparse Jacobian computation by only considering the degrees of freedom of the nodes within each specific cell. This change gives a speedup of about 10x on a 3x3x3 model.
PiperOrigin-RevId: 902164069
Change-Id: I78eedf1d5cf39b8989fe9863c22d164922fc0efb
This change introduces a `flex_cellcount` field to `mjModel` to specify the number of cells in each dimension for interpolated flexes. The stiffness computation, passive force calculation, and Jacobian derivatives are updated to operate on a per-cell basis, significantly improving performance by localizing computations to the nodes within each cell.
PiperOrigin-RevId: 901216393
Change-Id: Ic23132e609de11e71bb7fef8d1f139daad2ec264
This default forces users to use the `spec.assets` dictionary or to do other filepath gymnastics when loading URDF. Instead we encourage users to just modify file paths directly if necessary.
PiperOrigin-RevId: 899009853
Change-Id: I4bb84606a95b65be79ccc77ccbe78062d6de8773
- Remove `lugre:viscous`, should now be added directly to actuator `damping`. Trying to do this for the user was incompatible with default inheritance (compounding instead of overriding).
- Move voltage limiting from the `saturation` to the `controller` attribute.
- Fix indexing issues in default inheritance.
PiperOrigin-RevId: 897087642
Change-Id: I5388c2633e15c7e223992e7eb5d6a28db75a6438
The `vertcollide` attribute in flex and flexcomp contact specifications has been removed since the next mjWarp release will support flex collisions. This attribute was previously used to enable vertex-based collisions by adding sphere geoms at flex vertices. The functionality associated with this attribute has been deprecated and removed from the XML parser, documentation, and internal data structures. Affected example XML files have also been updated.
PiperOrigin-RevId: 885595503
Change-Id: I6a78975f1bc540c09ea8b5306ff3be0962b7ab24
Add usd_decoder to mujoco/plugin.
- Previously was src/experimental/usd/usd_to_mjspec.cc, now that same spec is returned by the plugin.
PiperOrigin-RevId: 854350962
Change-Id: Ia980190a557c50ce8197980922a2594b613859b4
This allows us to remove the special "LoadModelFromString" resource provider.
PiperOrigin-RevId: 854207845
Change-Id: I6d00f2ab99b4351866e1d39dbeed96f29aaaf915
This removes the need for a custom mjResourceProvider, but does require
reimplementing part of mj_loadXML in the fixture.
PiperOrigin-RevId: 854170820
Change-Id: Ib455cc5cdb5138213eb7e996dc32ac156f22a859
Yuval Tassa