Abstract: Based on the idea of bar deformation in mechanics of materials, a new deformation method is presented. Firstly, a local coordinate is specified. Subsequently defined is an elastic bar with circle shaped cross section, which takes x-axis of local coordinate as the central axis. The primitive is embedded in the bar globally or locally. Finally, after imposing displacement boundary conditions (such as fixed or hinged constraint) and external loads (such as axial loads, radial loads, bending couple and torsion couple, et al) on elastic bar, the primitive will be deformed as a part of the bar. Using this approach, stretch, bending, twist and taping can be accomplished. The proposed method is independent of the representation of the object, and can be applied to the modeling of mechanic hardware such as screw thread, aiguille and spring. Examples show that the presented method is potential useful in the field of CAD/CAM.

Key words: Free-form deformation, Geometric modeling, Mapping, Mechanics of materials