DEScription temPLATEs

This repository contains various examples for how to template description files in ROS 2. Each example demonstrates the use of a templating engine, with a description format, at compile time or launch time. All examples have the same final result, which makes it easy to compare them side-by-side.

Templating engines:

• 🐍 EmPy
• 💎 ERB
• 📟 Xacro

Description formats:

• 🌱 SDF
• 🌐 URDF

Is your engine or format of choice not represented? Consider opening a pull request to add it!

Quick start

1. Install ROS Humble or higher

2. Clone this repository:

    mkdir -p ~/ws/src
    cd ~/ws/src
    git clone https://github.com/chapulina/desplate
    

1. Install dependencies:

    cd ~/ws
    rosdep install --from-paths src --ignore-src -r -y
    

1. Build and install:

    cd ~/ws
    colcon build
    

1. Run one of the examples, i.e.:

    ros2 launch desplate_empy vehicle_sdf_generate.launch.py
    

1. You should see a differential drive robot (like dolly) on RViz:

   

2. Also try checking the inertia visualization:

   

Try out all examples

How it works

Launch time

Generating description files at launch time is convenient if you’re often iterating on parameters for those files. On the other hand, if your files aren’t changing much, consider generating them at compile time to save some time every time you launch.

Generate templates at launch file following these steps:

1. Install all template files, i.e.:

   https://github.com/chapulina/desplate/blob/86b7960169b02fc4fbd4765f9fe9e1342af3ac33/desplate_empy/CMakeLists.txt#L39-L46

2. In a launch file, get the path to the installed template file, for example:

   https://github.com/chapulina/desplate/blob/86b7960169b02fc4fbd4765f9fe9e1342af3ac33/desplate_empy/launch/vehicle_sdf_generate.launch.py#L30-L31

3. Use the templating engine to generate a file and store it in a string variable.

File truncated at 100 lines see the full file