It might be to do with the size of the model. By default maya only shows so much on screen, so large scenes will disappear partialy. I think there is an option in Maya, Windows > Preferences. Cant get it atm whilst at work. So if anyone knows straight off the option I mean please stick it in the post, if not I will post the solution when I am home.
Chris (formerly R@nSiD)
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Winner SM VFX Challenge 1
3rd Place SM SteamPunk Challenge (May 2007)