“…Recent skeleton-based reverse engineering approaches choose to extrude primitive cross-sections along these skeleton lines (Cuillière et al, 2018;Nana et al, 2017;Stangl and Wartzack, 2015) or apply free form surface reconstruction (Bremicker et al, 1991;Denk et al, 2021b). Afterward, the shape is assembled using an implicit representation CSG of these cylindrical primitives (Cuillière et al, 2018;Nana et al, 2017) or connecting the control points of the explicit free form surfaces (Bremicker et al, 1991;Denk et al, 2021b). The fundamental concept of these medial balls of the unification of each ball is covered by the unification of cylinders and spheres (Cuillière et al, 2018;Nana et al, 2017) or the selection of reasonable control point positions (Bremicker et al, 1991;Denk et al, 2021b).…”