<p>Is there a way to make all your prints seamless?? I know there was this program that printed a vase constantly changing the z axis making it seamless. Why cant this be done with regular prints?</p>

If you ever seen 3d printouts on your own and you did keep it in hand then you probably felt layers. Most printouts contains 3 main "components"
bottom and top component (floor and ceiling)
outline (perimeters)
infill (inside supporting structure)
It is almost imposible (and for sure sensless) to create all these components with one continues line as it would be very complex and sophisticated line.
Second reason. It would be very often that printer would cross outlines (perimeters) so it would destroy good looking external surface.
And third reason. Objects can have "islands". Imagine printed elephant which is standing on 4 legs. How to draw leg leyers with one line if these legs are separated (at the floor level).
That's why "round vase" is the only option to print seamless. :)