Here, r is the radius of the helix and h is a parameter describing the vertical separation between each loop of the helix that is related to the pitch. The angle is defined as shown in Figure . A cylindrical helix is a curve that forms a constant angle with respect to the axis of the cylinder. Intrinsic to this definition, it has constant non-zero curvature and constant non-zero torsion. Curvature and torsion are defined by