Commit Graph

5 Commits

Author SHA1 Message Date
Sam Haves f434578d30 USD decoder improvements: Support actuators targeting tendons and improve side site index handling.
Adds support for mjTRN_TENDON actuators in the USD decoder. Modifies the tendon path parsing to correctly handle side site indices, allowing -1 to signify no side site for a given path element.

PiperOrigin-RevId: 862755621
Change-Id: I18b13b160e3d1c27945d0972a69012d6307131e9
2026-01-29 08:51:02 -08:00
Sam Haves 2582a83ac3 Add equalityJointAPI to mjcPhysics.
PiperOrigin-RevId: 860081702
Change-Id: Ifd961dcb2a8e0f5d885e9e9dadc0153b03cb5f4d
2026-01-23 06:28:29 -08:00
Sam Haves c08e1d9e6e Add MjcEqualityAPI as a base class for MuJoCo constraints and MjcEqualityWeldAPI for representing weld constraints.
This change introduces two new USD API schema:
* MjcEqualityAPI - base API for representing MuJoCo equality constraints in USD, this will typically be applied to joints such as UsdPhysicsFixedJoint.
* MjcEqualityWeldAPI - extends MjcEqualityAPI for MuJoCo's weld equality constraints with an attribute for torqueScale.

The usd_decoder is updated to parse UsdPhysicsFixedJoints and convert the new schema attributes into the appropriate mjsEquality data fields.

PiperOrigin-RevId: 856723634
Change-Id: I0982fd3168b643f8e91d87bb5ae5933e526b63a1
2026-01-15 10:44:27 -08:00
Sam Haves d816b38f4c mjcPhysics MjcTendon path now has an indices attribute to allow repeated sites in tendon path.
Since relationships in USD can only contain a single instance of a path, it was previously impossible to have a tendon path that visits the same wrap target more than once. This is a fairly common occurence when dealing with tendons that have pulleys.

With this change, if mjc:path:indices is not defined then the behaviour is as it was and the mjc:path is considered to be ordered. If it is authored then the parser will use the indices into mjc:path as the order. This mirrors other similar concepts in USD such as face vertex indices.

PiperOrigin-RevId: 856339887
Change-Id: I6b9503973de377acdb0689be168c16e4aa19b70b
2026-01-14 13:24:28 -08:00
Sam Haves a5dc57c0c3 Move OpenUSD parsing to usd_decoder
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
2026-01-09 14:48:29 -08:00