InfernalDarkness, TG has been in development for years, with only 3 or 4 developers, so it took a lot more time than scheduled and  without enough cash, I suspect  ( Matt, the one who created TG, had to take 6 month break from TG2 and work at Digital Domain)  and users were getting impatient, and maybe going the Vue or Carrara way. So Planetside released the "Technology preview", which is not the final product, but allows users and fans of Terragen to play with it, and buy the final version along, thus giving Planetside a little cash to keep on working on TG2 development ( the last bit is only me speculating) in the process.