Round Horizontal Cylinder Give me Cigar Shape?

[Zowie]

Hi all,
I'm trying to show ducting on a gallery ceiling, thought we had round ducting in the library, but can't seem to find any, so I tried using horizontal cylinders but they show up as oblong in 3d. Anyone know where there are some proper vents or how to make these cylinders show up as cylinders?

Thanks much,
Zowie