PyGeo: a dynamic geometry toolkit

circles

circle oriented in space

f Circle() ...

factory function returns instance a class representing the set of points of a plane equidistant from a given point of the plane

constructors:
Circle (point1,point2,plane )
circle of the given plane with 1st given point at center, 2nd point on circumference
Circle (point1,point2,point3 ,CIRCUM )
circle passing through the 3 given points
Circle (circle,point )
circle with center at the given point and orthogonal to the given circle
Circle (point1,point2,point3 ,EXSCRIBED )
circle exscribed in the 3 given points' triangle, in the side opp the 1st point
Circle (point1,point2,point3 )
circle with first point at center, second on circumference and on the plane of the 3 points
Circle (point1,point2,point3 ,INSCRIBED )
circle inscribed in the 3 given points' triangle
Circle (sphere1,sphere2 )
circle section determined by the intersection of the 2 given spheres
Circle (sphere,plane )
circle section of the intersection of given sphere and given plane

See the source for more information.