The Plugin was tested on Windows 10 and Ubuntu Linux 22.04 LTS using Unreal Editor 5.1.

Prerequisites

• Install Unreal Editor and set up visual studio
• For installation on Linux, have a look here
• Have a Unreal Project using Unreal Engine 5.1
• Read the Editor Interface and Engine Terminology basics

Installation

• Download the Sensors plugin
• Move it to the Plugins folder of your project, create one if it does not exist
• Open your Unreal Project
• Go to Window->Plugins and activate the Sensors plugin which is located under PROJECT/RRLab. For more info check this link
• Restart the Editor
• If you are asked to rebuild now, press Yes. This will compile the Editor and also the plugin.
• If the editor starts again with no error messages, the Plugin is activated

Setup

To check the content in Unreal, do the following:

• Open the Content Browser
• In the upper right corner of the Content Browser, click on Settings
• Check Show Plugin Content
• On the left of the Content Browser, you should now see a folder Plugins containing Sensors Plugin Content and Sensors Plugin C++ Classes

Export annotated pointclouds

1. Drag a RayTracingLiDARActor in to your scene, it can be found in Plugins/Sensors Plugin C++ Classes/LiDAR/
2. Adapt the parameters (RayTracingLiDARActorParameters) of the sensor, they can be found in the Details panle
3. Make sure to check UseRGBOutput and WriteObjectID
4. Under the SensorParent category, change the TickInterval variable since it defines the frequency of the sensor (writing to a file is very slow in comparison to creating the pointcloud in the simulation)
5. In the AdapterComponent of the Sensor copy the path of your file to the FilePath variable
6. To set the ObjectID, follow the following steps:
7. The ObjectID of an Actor is defined as the first entry of the Tags array if that is a number, otherwise it is -1
8. Select an actor that should have an ObjectID
9. Under the Category Actor click on the arrow to show the advanced settings
10. Add an element to the Tags array
11. The first entry is interpreted as a number defining the ObjectID
12. Start the simulation
13. After TickIntervall seconds, the pointcloud should written to the file you have selected
14. You can check the Output Log or command line for error messages

Usage of Particle Lidar

1. Navigate to PluginsSensors Plugin Content"/LiDAR/ParticleLidar and drag BP_ParticleLidar into the scene
2. Parameters such as the channel count can be directly adjusted in the Details panel. To disable the particle rendering, open PS_LidarParticleSystem, and disable Sprite Renderer
3. The point cloud can either be used in the C++ class ParticleLidar.cpp or in the Blueprint BP_ParticleLidar.cpp. It’s also possible to use the prebuild Adapters.

See a real-time demo of the sensor here:

Move sensor along spline

For recording sensor data on a fixed path, there is a spline utilizing an event-based sensor setup.

1. Drag the SplineFollow class into your scene, it can be found in Plugins/Sensors Plugin C++ Classes/Utils/
2. Adjust the spline according to your needs, note the following:
   1. The sensor records at every spline point.
   2. There is no recording at the first and last spline point.
   3. The detection of a spline point is done via collision overlap, so your sensor needs to have a mesh with collision
3. Drag a sensor into your scene
4. In the SplineFollow actor, set the variable Sensor as a reference to your previously spawned sensor.
5. Adjust the Timestep according to your application if needed. Every EventTick, the value Timestep is added to the current time on the spline.
6. Start the simulation.
7. Check the start variable of the SplineFollow actor, the sensor should now move along the spline

License

Copyright (c) 2023 Robotics Research Lab, University of Kaiserslautern-Landau

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.