mujoco

2.2.0

Star
Multi-Joint dynamics with Contact. A general purpose physics simulator.
robotics physics mujoco
google-deepmind/mujoco

What's New

2.2.0

2022-05-23T12:25:59Z

Open Sourcing

  1. MuJoCo is now fully open-source software. Newly available top level directories are:

    1. src/: All source files. Subdirectories correspond to the modules described in the Programming chapter introduction:
      • src/engine/: Core engine.
      • src/xml/: XML parser.
      • src/user/: Model compiler.
      • src/visualize/: Abstract visualizer.
      • src/ui/: UI framework.
    2. test/: Tests and corresponding asset files.
    3. dist/: Files related to packaging and binary distribution.

  2. Added contributor's guide and style guide.

General

  1. 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.

  2. 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 use velocity actuators. For more details, see the Numerical Integration section.

  3. Added actlimited and actrange attributes to general actuators, for clamping actuator internal states (activations). This clamping is useful for integrated-velocity actuators, see the Activation clamping section for details.

  4. mjData fields qfrc_unc (unconstrained forces) and qacc_unc (unconstrained accelerations) were renamed qfrc_smooth and qacc_smooth, respectively. While "unconstrained" is precise, "smooth" is more intelligible than "unc".

  5. 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>.

  6. The default shadow resolution specified by the shadowsize attribute was increased from 1024 to 4096.

  7. Saved XMLs now use 2-space indents.

Bug fixes

  1. Antialiasing was disabled for segmentation rendering. Before this change, if the offsamples 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 change offsamples is ignored during segmentation rendering.

  2. 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.

  3. Fix issue of duplicated meshes when saving models with OBJ meshes using mj_saveLastXML.

Update 1 (27 May 2022): Replaced Linux tarball to fix RPATH on the sample binaries. No change in functionality.

MuJoCo Physics

MuJoCo stands for Multi-Joint dynamics with Contact. It is a general purpose physics engine that aims to facilitate research and development in robotics, biomechanics, graphics and animation, machine learning, and other areas which demand fast and accurate simulation of articulated structures interacting with their environment.

This repository is maintained by DeepMind, please see our acquisition and open sourcing announcements.

MuJoCo has a C API and is intended for researchers and developers. The runtime simulation module is tuned to maximize performance and operates on low-level data structures that are preallocated by the built-in XML compiler. The library includes interactive visualization with a native GUI, rendered in OpenGL. MuJoCo further exposes a large number of utility functions for computing physics- related quantities. We also provide Python bindings and a plug-in for the Unity game engine.

Documentation

MuJoCo's documentation is available at mujoco.readthedocs.io, which serves webpages derived from the documentation source files.

Releases

Versioned releases are available as precompiled binaries from the GitHub releases page, built for Linux (x86-64 and AArch64), Windows (x86-64 only), and macOS (universal). This is the recommended way to use the software.

Users who wish to build MuJoCo from source, please consult the build from source section of the documentation. However, please note that the commit at the tip of the main branch branch may be unstable.

Getting Started

There are two easy ways to get started with MuJoCo:

  1. Run simulate on your machine. This video shows a screen capture of simulate, MuJoCo's native interactive viewer. Follow the steps described in the Getting Started section of the documentation to get simulate running on your machine.

  2. Explore our online IPython notebooks. If you are a Python user, you might want to start with our tutorial notebooks, running on Google Colab:

  • The first tutorial focuses on the basic MuJoco Python bindings: Open In Colab.

  • The second tutorial includes more examples of dm_control-specific functionality: Open In Colab.

Citation

If you use MuJoCo for published research, please cite:

@inproceedings{todorov2012mujoco,
  title={MuJoCo: A physics engine for model-based control},
  author={Todorov, Emanuel and Erez, Tom and Tassa, Yuval},
  booktitle={2012 IEEE/RSJ International Conference on Intelligent Robots and Systems},
  pages={5026--5033},
  year={2012},
  organization={IEEE},
  doi={10.1109/IROS.2012.6386109}
}

License and Disclaimer

Copyright 2021 DeepMind Technologies Limited.

Box collision code (engine_collision_box.c) is Copyright 2016 Svetoslav Kolev.

ReStructuredText documents, images, and videos in the doc directory are made available under the terms of the Creative Commons Attribution 4.0 (CC BY 4.0) license. You may obtain a copy of the License at https://creativecommons.org/licenses/by/4.0/legalcode.

Source code is licensed under the Apache License, Version 2.0. You may obtain a copy of the License at https://www.apache.org/licenses/LICENSE-2.0.

This is not an officially supported Google product.

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Dependencies

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Last updated: Fri Apr 19 2024 02:18:21 GMT-0900 (Hawaii-Aleutian Daylight Time)