Surface of revolution is created by spinning a 2 dimensional curve about an axis that you specify. The revolution is any amount from 0
up to 360 degrees. These are similar to a swept surface, but can be used to create other primitive shapes not provided such as a torus or a cone.
These surfaces are exact.
Revolved surfaces may have no cap on the ends depending on the source curve. Depending on the milling technique you select, such as Z-level roughing, you may need a cap surface.