Hi there!
I played the game on Mac OS and Windows 7 now and in both games I’m not able to research higher versions of the 3D Engine. Is this on purpose or a bug? Or has 3D engine research been changed since last version of Game Dev Tycoon?
You will have to use earlier 3D versions to unlock higher level ones. There is no change to that in the newer version. Works the same as before.
Or he probably reached the time for 3D Engine V6 which he has to research with R&D lab?