1/27, 3 - 8 PM: found that programs in Unity3D for HTC vive don't work any more (error: invalid matrix & failure to render the controllers);
figured out it was the problem raised by the newest version (v1.2.3) of SteamVR Plug-In for Unity;
solution: use the last stable version instead (v1.2.2 from Github)
1/29, 1:45 - 2:10 PM: created journal page