This 7-sided bowl is the 3rd update to the geometry used in https://www.thingiverse.com/thing:3047912. There is info there about squircles and how I used them to make these shapes. This blog page shows the software I use and how it makes changes to geometry easy to do: http://birkbinnard.com/blog/parametric-modeling/.
This part printed in 9 hrs. 20 min. using a layer height of 0,200 mm and a print speed of 100 mm/sec.