Basic information

Online documentation

https://rclUE.readthedocs.io/en/devel/

Supported versions

• Ubuntu 20.04
• Unreal Engine 4.27
• ROS2 Foxy
• Clang: 11.0.1 (from UE)

Please setup UE4 by following Linux Quick Start

Branches

master

This build of the plugin is based on ROS2 Foxy and has been tested on Ubuntu 20.

This branch currently represents the release branch.

Other branches

Experimental and WIP

RclUE and ROS2

Description

• We use ros2 'foxy' lightweighted (not all binaries are included). Source/ThirdParty/ros folder is fully autogenerated by Scripts/update_ros.py (check script to see what is actually includes).
• ros includes UE_msgs
• Ros2 middleware, Product name: eProsima Fast DDS, License: Apache 2, RMW implementation: rmw_fastrtps_cpp
• to use this plugin change the world settings to use meters as units instead of the default centimeters
• within the Unreal Editor: Edit->Plugins, search and enable for rclc

Windows is currently unsupported

Getting Started

The plugin folder contains a video "Example_BP_PubSub.mp4" demonstrating how to setup a PubSub example in Blueprint.

An example setup using this plugin can be found at turtlebot3-UE

Notes on working with ROS2 and UE4

• rcl and void* types cannot be managed by UE4 (no UPROPERTY) and therefore can't be used directly in Blueprint. Whenever access to these variables is needed, the user should write a class to wrap it and all of their handling must be done in C++.
• some basic numerical types are not natively supported in Blueprint (e.g. double, unsigned int). In order to use these, a workaround is needed (a plugin implementing those types for BP, a modified UE4 or a custom implementation).
• In autogenerated messages, the method MsgToString() should be implemented by the user as its current purpose is to help debugging.

How to update ROS inside RclUE

Currently there is a Scripts/update_ros.py for automatic build and update ROS2 (foxy) libraries. To update ROS:

• Install 'ros2' (foxy) (until section 'Build the code in the workspace') Building ROS 2 on Ubuntu Linux
• Reinstall python package due to issue:

sudo apt remove shiboken2 libshiboken2-dev libshiboken2-py3-5.14
pip3 install --user shiboken2

• Apply patch for ros2 to avoid setting LD_LIBRARY_PATH environment variable to the dynamic libs paths:

src/ros2/rcpputils/src/find_library.cpp:
in function find_library_path():
---//return "";
+++return "lib" + library_name + ".so";

• Clone 'rclc' package, branch 'foxy' (it's not a part of official ros2)
• Clone 'ue_msgs' (Rapyuta-Robotics project)
• Run Scripts/update_ros.py script with arguments:

python3 update_ros.py <Path to UE4> <Path to ROS2 foxy> <Path to rclc package> <Path to UE_msgs> <Path to project, which includes RclUE plugin>
For example:
python3 update_ros.py /home/vilkun/UE/UnrealEngine /home/vilkun/ros2_foxy /home/vilkun/work/build_foxy/rclc /home/vilkun/work/build_foxy/UE_msgs /home/vilkun/work/turtlebot3-UE

Notes:

• Script also updates Rapyuta-Robotics UE_msgs libraries inside RclUE.
• Please check the scripts for more details about how it deals with libraries versions in their SONAME (UE4 can't deal with it, see 2 potential fix ways)

Documentation

Tools

documentation is built with three tools

• doxygen
• sphinx
• breathe

Locally build

1. install tools in #tools section.
2. build

   cd docs
   make --always-make html
   

3. Open following in your browser.
   • Sphinx at file:///<path to cloned repo>/docs/source/_build/html/index.html
   • Original doxygen output at file:///<path to cloned repo>/docs/source/_build/html/doxygen_generated/html/index.html

Maintainer

yu.okamoto@rapyuta-robotics.com