Unity's Input System does not support HID devices on Linux, so we cannot use it. Thankfully, there already is a good open-source driver for 3DConnexion 6DOF devices called spacenavd, so we can rely on it instead.
If you've installed Unity from snap or flatpak, then SpaceNavigator will not work. Install Unity via Unity Hub instead. See this guide for RPM-based distros.
If you insist on using a sandboxed environment, please configure it so that the file /var/run/spnav.sock
is exposed to the sandbox.
For Ubuntu and other Debian-like systems, you can just sudo apt install spacenavd libspnav0.
For Fedora, it's sudo dnf install spacenavd libspnav.
Before you continue, make sure the driver works by trying it out in another application like Blender.
Create a file under /etc/spnavrc with the following contents:
socket=/var/run/spnav.sock
Enable the service with sudo systemctl enable spacenavd
Then start the spacenavd service with sudo systemctl start spacenavd, the blue light on the device should now come on.
If you are successful, the output of file /var/run/spnav.sock will look like this:
/var/run/spnav.sock: socket
... as per instructions in the main README file. Your 6DOF device should now work in the editor. If it doesn't, try unchecking the "Only navigate when Unity has focus" option.