Epitrochoids and Hypotrochoids

This is a Public Domain OpenSCAD file with epitrochoids and hypotrochoids.These shapes are useful for making mechanisms likeRoots Blowers http://www.thingiverse.com/thing:8068Wankel Engines http://www.thingiverse.com/thing:8069and Moineau Pumps http://www.thingiverse.com/thing:7958An EPITROCHOID is a curve traced by a pointfixed at a distance "d"to the center of a circle of radius "r"as the circle rollsoutside another circle of radius "R".An HYPOTROCHOID is a curve traced by a pointfixed at a distance "d"to the center of a circle of radius "r"as the circle rollsinside another circle of radius "R".An EPICYCLOID is an epitrochoid with d = r.An HYPOCYCLOID is an hypotrochoid with d = r.See http://en.wikipedia.org/wiki/Epitrochoidand http://en.wikipedia.org/wiki/Hypotrochoid --- Imported from Thingiverse: https://www.thingiverse.com/thing:8067 Original creator: mattmoses