After my motherboard (and possibly the CPU) did die this weekend I had to build a new system from the remaining parts and some left-overs. Now that I re-installed TG the sky in the 3D preview is fragmented. This happens with 'Visible Atmosphere' enabled as well as with 'Visible Atmosphere' disabled.
In the past this never happened except when I was running a Remote Desktop session.
Try adjusting the clipping plane in the 3D preview with the [ and ] keys. Also make sure you have the latest graphics card driver.
- Oshyan
Thank you, Oshyan, the [ and ] keys did the trick. :)