Warning

Warning: Unity Simulation is deprecated as of December 2023, and is no longer available.

Save point clouds to disk

Use the Point Cloud Message Saver component to subscribe to a topic and save messages of type PointCloud2Msg as PCD or LAS files.

Add the Point Cloud Message Saver component

You can export point clouds generated by your sensors as PCD or LAS files by performing the following:

Select any GameObject in your scene.
Select Add Component in the Inspector, and choose Point Cloud Message Saver.
Set Topic to the topic the sensor is publishing to. The topic must be of type PointCloud2Msg.
Enter Play mode.
Select Open next to Save Directory to open your file browser where the file has been saved.

Configure the save directory

Set the Save Directory to the path where you want to save the point cloud files to. You can use the browse button (denoted by ...) to use a file dialog to find the desired path.

If you leave the path empty, the path defaults to Application.dataPath.

Configure the saving behavior

The Point Cloud Message Saver uses the File Name pattern you specify, replacing %n (if found) with a zero-padded four-digit index of the capture.

The extension of the point cloud file can be chosen by setting the File Type drop down to the desired type, which can be either PCD for .pcd file extension or LAS for .las file extension.

By default, any existing file with the same name is overwritten. Disable Overwrite to skip to the next available file index.

Save point clouds automatically

By default, Capture On Start is enabled, which instructs the Point Cloud Message Saver to start saving point clouds automatically when the simulation starts.

Set Number Of Captures to specify the number of files you want to save. Set it to 0 to save files until the simulation stops.

You might want to skip the first few files generated by your sensors, which can be done by setting Start Time to the simulation time when the export should start.

Distributed Rendering considerations

If you are using Distributed Rendering to improve performance, you can configure the Point Cloud Message Saver so that each Client saves point cloud files locally for the sensor it is rendering. Note that Distributed Rendering is currently only compatible with the Raster-based LiDAR.

Add the Point Cloud Message Saver component to the same GameObject as the Distribution Affinity component used to specify on which render node the sensor runs.
Consider changing the File Name property to include the group ID. For example, set File Name to point_cloud_2_%n if the Distribution Affinity group for the sensor is set to 2.

Limit the number of files saved

By default, all files are saved to disk, up to the number you specify in Number Of Captures. If the sensor update rate is high, this might generate too much disk activity and slow down the simulation.

To limit the number of files saved per second, set Time Between Captures to the minimum number of seconds that must elapse before saving the next file.

Save files interactively

The Runtime Controls appear in the Inspector when you enter Play mode in the Editor. You can use Start and Stop to control file export interactively.

You can use the Point Cloud Message Saver to save files from the Editor during Play mode:

Disable Capture On Start.
Set Start Time to 0.
Enter Play mode.
Use the visualization suite to determine when it's appropriate to save the point cloud file.
Use Start in the Runtime Controls to save the file to the type you have set.

The Status indicates the current state of the Point Cloud Message Saver.

Status	Description
Ready	The export hasn't started yet.
In progress	The Point Cloud Message Saver is waiting for more point cloud messages to save.
Success	The files have been saved successfully.
Stopped	You manually stopped the last file export before it had time to complete.
Timed out	No message was received on the specified topic during the last file export. Ensure Topic corresponds to the sensor's output topic.
Exception	An exception occurred during the last file export. Check the console or the logs for more details.

Viewing saved files

Point cloud files can be difficult to interpret as is, so they can be visualized using external tools like this website for LAS files or this website for PCD files, or by writing custom scripts such as the following Python script for PCD files:

from open3d import *

def main():
    cloud = io.read_point_cloud("PATH-TO-PCD-FILE.pcd")  # Read point cloud
    visualization.draw_geometries([cloud])    # Visualize point cloud

if __name__ == "__main__":
    main()

Point Cloud Message Saver Inspector reference

Property	Description
Topic	The topic to save messages from. The topic's message type must be `PointCloud2Msg`.
Number Of Captures	The number of files to save. Set to 0 to save files indefinitely.
Start Time	The delay in seconds to wait before acquiring the first file. Set to 0 to capture the first received message.
Time Between Captures	The minimum time in seconds to wait between messages, skipping intermediate messages if necessary. Set to 0 to never skip messages. Has no effect when exporting only 1 file.
Save Directory	The path used to save files. If left empty, defaults to Application.dataPath.
File Name	The file name pattern used for files. If found, `%n` is replaced by the file index. Can't be empty.
File Type	The file extension to save to. The extension can be either `.pcd` or `.las`.
Overwrite	Whether to overwrite destination files if they exist. If File Name doesn't contain `%n`, this option is ignored and the file is always overwritten.
Capture On Start	Whether to automatically start the export when entering Play mode or when launching the executable.
Log To Console	Whether to log information messages to the console.