The zoom to fit command (hotkey "F") is a great way of showing the whole part, assembly or drawing so it fills the screen. However in an assembly it can give you unexpected results making the assembly seemingly disappear. This is actually because one or a number of part models are positioned a huge distance from the rest of the geometry and assembly origin. SOLIDWORKS is actually doing the right thing but these erroneous parts are causing the issue.
After a support call, logged with SOLIDWORKS, they pointed me in the direction of the "Magic Button." if you run into this difficulty click Tools > Assembly Xpert
and there will be a button (the spanner/ wrench icon) which will literally pick up these problem parts and move them to a more sensible position. What's more this button is not new- I found it in SW 2011 as well. This is documented in the online help too if you want to check it out (link
This certainly beats my previous advice of hiding and showing parts until you find the culprit!!
Adam Hartles | Training Manager
Solid Solutions Management