For glass whorl making, bobbles have a purpose beyond looks. They add a little weight to the whorl, which often seems like a good thing. And if they are placed all around the outside, they can also affect the speed and length of the spin. Oh, it's physics, and I am not so good with physics. But it does change how things go around.
To quote Wikipedia: 'Whorl shapes vary greatly and can include ball-shaped, disk-shaped and cross shaped whorls. The shape and mass distribution of the whorl affects the momentum it gives to the spindle while it is spinning. For example a center weighted whorl will spin very fast and short, while a rim-weighted disk-shaped whorl will spin longer and slower.[9]'
So, first I make a nice smooth whorl. Then maybe I add some swirls here and there, either evenly all around the bead, or maybe just randomly. Then I wonder if it might need just a little more weight, or if accent bumps would look nice. And then, well, does it need raised bumps around the center to make it spin a bit longer? And, if it happens to be a sea urchin whorl, then bumps and bobbles are a definite part of the design!Oh, looking through that article, I see spindles are associated with a number of goddesses. Hmmm... going to have to let the brain wheels spin around that for a bit!