Full support for using a 3Dconnexion device in the 3D viewer has been added. Full 3D navigation is available for both the orthographic and perspective projections. Commands are exported and can be assigned to 3D mouse buttons. Any limitations to the functionality are limitations of the installed 3Dconnexion driver for the device and OS.
ADDED: A build option KICAD_USE_3DCONNEXION (default = ON) has been added to the main CMakeLists.txt. The option controls whether the SpaceMouse support is compiled into the solution.