On Sun, 22 Mar 2009 22:36:59 -0500, "Leon"
wrote:

No come to think of it I have had s strange situation pop up now and then
using SU, have you seen this happen? Occasionallay when zooming or panning
part om my drawing will disappear like I cut a section away. Rotating,
panning or zooming will not correct the problem. The permanent correction
is to zoom extents and then go back to where I was when part of the drawing
diasppeared.

Sounds like "Z-clipping" to me. Part of the 3-D extents of the model
are "behind" the camera position and cannot be seen from the camera
location. Search the SketchUp help group for "Camera Clipping". There
are a number of suggestions as to the cause and corrections.

Tom Veatch
Wichita, KS
USA