Maya Instructions:
I did not have a copy of maya when I made this model. These instructions will give a result similar to the previews above:

1. Merge Vertices at 0.001 tolerance
2. Preform poly Clean-up with Zero edges and faces with Zero geometry checked.
3. Delete history
4. Convert to Subd surface
5. Convert to poly surface using vertices level 0

6. Average vertices. I used the default of 10 iterations. You can use more or less or specifically smooth certain areas.
7. Smooth proxy. Exponential or linear work.