Extrude Radius Factor Calculator

Calculates an extrude radius factor based on a desired lip offset.

Note that specifying a lipOffset of greater than what is possible to extrude by setting a radius to be very large, erroneous results will be generated.

radius:		The radius of the object being generated.
slices:		The number of slices the generated object's curve is made of.
extrudeTopNSlices:		This should be set to whatever the value is set to for the object being generated.
lipOffset:		The number of units the top edge of the circular arc is to be nudged outward.