I'm having an issue with the 3DCLIP command temporarily flipping the viewport that I'm clipping to the incorrect view thus I can't preview the slices in the viewport. For example, if I'm clipping a front view the viewport flips to the top view before displaying the 3DCLIP window. The top view is exactly what appears in the 3DCLIP window. I am running AutoCAD 2011 64 bit in Windows 7 64 bit with the NVIDIA Quadro FX 5800 and the latest drivers installed. By the way, I had to download the latest NVIDIA drivers due to the "Heidi" error.