I would go to Turbosquid to get any 3rd party models...
if its a native file mb or ma then just open them, if not then import them with the correct import tool...
IF you are getting a white screen on opening the files... check out the size of the file... If its a biggie this will take time to load. If not them it might be corrupt.... You cant get summin for nuthin Im afraid...
Chris (formerly R@nSiD)
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When the power of love overcomes the love of power the world will truely know peace - Jimmy Hendrix
Winner SM VFX Challenge 1
3rd Place SM SteamPunk Challenge (May 2007)