Hi Brendan, yes as others mention above the kind of layering effect that you're seeing there is a part of the printing process, there isn't anything you would do about that in the STL file generation itself.

If you've seen smoother prints from the same machine previously, it could be possible that the machine needs to be recalibrated or that there was some kind of post processing done on the smoother parts that you saw, like sanding, tumble polishing, acetone dip, stuff like that. You might want to ask him about what process he used on the smoother parts that you saw so that you could get the same thing done on your parts too.

It's really cool to see your model manifested in physical form!

- Michael