3D model display distorted

[bilbao]

I have a 3D model which when shaded (gouraud) distorts cylindrical objects,things that should be in front are at the back and portions of the cylindrical parts are missing.I have a nvidia video card and I am running acad2000i.Any help would be greatly appreciated.

 

[borgunit]

First, eliminate possible errors by running latest nvidia drivers and autocad service packs.

JRWalker

"Whether you think that you can, or that you can't, you are usually right "
.. Henry Ford