SphericalKernel::ConstructCircularSourceVertex_3

A model fo of this concept must provide:

SphericalKernel::Circular_arc_point_3
fo ( SphericalKernel::Circular_arc_3 a )
Constructs the source vertex of a.

SphericalKernel::Circular_arc_point_3
fo ( SphericalKernel::Line_arc_3 l )
Same, for a line segment.