FAQ: How to Add Custom Messages in ROS

• Yutian (Tim) Fan
• Dec 13 2024
• ROS version: Noetic

Advantages of Custom Messages

• Enable custom communication tailored to specific use cases.
• Improve code clarity by organizing data into structured messages.
• Reduce the need for parsing generic messages in your nodes.
• Facilitate efficient collaboration by defining clear data contracts between nodes.

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Steps to Create a Custom Message

1. Create the .msg Files

• Inside your package directory, create a msg folder to store the custom .msg files.
• Define your message file using the format:

  dependency/data_type name
  

• Example: For a message representing a frontier:

  geometry_msgs/Point centroid
  int32 size
  

2. Edit CMakeLists.txt

• In the find_package() section, add message_generation:

find_package(catkin REQUIRED COMPONENTS
  ...
  message_generation
  ...
)

- Uncomment add_message_files() and specify your .msg files:

add_message_files(
  FILES
  Frontier.msg
  FrontierList.msg
  PathList.msg
)

- Uncomment generate_messages() and include std_msgs under dependencies:

generate_messages(
  DEPENDENCIES
  std_msgs
  geometry_msgs
)

3. Edit package.xml

Add the necessary dependencies for generating and using custom messages:

<build_depend>message_generation</build_depend>
<exec_depend>message_runtime</exec_depend>

4. Build Your Workspace

• Navigate to your workspace directory:

cd ~/catkin_ws

- Run catkin_make to compile your workspace and generate the custom message files.