Curved edges shown as straignt edges

[MARK.PATERSON]

Ive already posted this in the MEP 2008 forum and it was suggested i post in here.
Im using Autocad MEP 2008 the current job im working on requires some tunnels to be drawn. Ive managed to do this by extruding a circle along a polyline and all looks good
But when i open navisworks and open the drawing either through exporting it or directly opening the DWG the tunnels all look like hexagons or Octogans any idea how to make them look like circles its very frustraiting.
I know that if you are to far away from the 0,0,0 origin the circle edges look more square but due to the project we are having to build the 3d model at actual grid references so its quite a distance from 0,0,0
Hope someone can help
Cheers

[Ferroequine]

I think you may already have answered your own question with the large coordinates. What happens when you create a test model located near the origin?

Since Navisworks is adaptive, do the tunnels still look funny when there is just a tunnel and no other entities?

[MARK.PATERSON]

yeah its the same even with a simple extruded circle at point 0,0,0 its the same

[-SL-]

This is kind of a shot in the dark, but what about changing (increasing) the VIEWRES in AutoCAD prior to exporting to NavisWorks?