I recently upgraded to 2013 from 2012. Once I did this upgrade, my 3D shaded model is now transparent. This seems to be a known problem in 2013. Does anyone know how to fix this problem?
Try updating your drivers for your graphics card. if that does not correct the issue you can try turning off hardware acceleration.
WE also had the same issue. It is indeed Graphics driver related. The latest graphics driver is not always work.
First make sure you know which graphics card you have in your PC.
Then please visit http://www.autodesk.com/graphics-hardware and input the three steps. Search and you'll find the correct Graphics driver version to download for your graphics card.