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  • User Guide
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Section Navigation

Getting Started

  • 🛠️ Install Python SDK
  • 🚀 Quick Start: Hello MotrixSim
  • MotrixSim Web Viewer
  • 📖 MJCF XML Reference

Comparison & Examples

  • 🛠️ Environment Setup
  • ⚖️ Case Comparison
  • 📚 Example Programs
  • 🦿 Legged Gym

Main Features

  • 🏗️ Model (SceneModel)
  • 💾 Data (SceneData)
  • 🔨 Model Building
  • ⚙️ Global Settings (Options)
  • ​🔀 Multi-Environment Parallel Simulation
  • 🦾 Inverse Kinematics (IK)
  • 🎯 Operational Space Controller (OSC)
  • 🎨 Renderer (RenderApp)
  • 🎮 Interactive Viewer

Kinematics

  • 🤖 Rigid Body (Body)
  • 🛸 Floating Base
  • 🔩 Joint
  • 📏 Link
  • 🔷 Geometry
    • Height Fields (HField)
  • 🔋 Actuators
  • 🌡️ Sensor
    • Accelerometer
    • Velocimeter
    • Gyroscope
    • Joint Sensor
    • Frame Sensor
    • Subtree Sensor
    • Touch Sensor
    • Contact Sensor
  • 📍 Site

Render

  • 📷 Camera
  • 🖼️ Widget Components
    • 📹 CameraViewport
    • 🖼️ ImageWidget

Indices

  • General Index
  • Python Module Index
  • User Guide
  • 📏 Link

📏 Link#

We refer to the rigid components in a multibody system as links. In MotrixSim, a link is an important concept representing each rigid part of a multibody system. Each link can have different properties and behaviors, and is connected to other links via joints.

link

MJCF Mapping#

When you use MJCF to describe a multibody system, MotrixSim maps all <body> elements to Link objects.

For the current support status of <body> tag attributes in MJCF, see MJCF Support Status.

Note

The <worldbody> element in MJCF is not treated as a Link object.

Main Interfaces#

In MotrixSim, you can access Link objects as follows:

  • model.num_links: Get the number of Link objects in the current world.

  • model.links: Get all Link objects in the current world.

  • model.get_link(key): Get a specific Link object by name or index.

Once you have a Link object, you can manipulate it using a variety of properties and methods. For more detailed APIs, refer to the Link API.

Example#

You can run a simple example demonstrating link API usage with:

uv run examples/link.py

See the source code at examples/link.py.

API Reference#

For more APIs related to Link, see Link API

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