A frame in 3D space. A triad of orthonormal basis vectors.
(<=> (3d-Frame ?F)
(And (Orthonormal-Basis ?F) (Basis.Dimension ?F 3)))
(Orthonormal-Basis ?F)
(<= (Basis.Dimension $X 3) (3d-Frame $X))
(<=> (3d-Frame ?F)
(And (Orthonormal-Basis ?F) (Basis.Dimension ?F 3)))
(Nth-Domain Orientation 2 3d-Frame)
(Nth-Domain Orientation 1 3d-Frame)