Sweep-based Approach to Three-Dimensional Shape Deformation

We present a sweep-based approach to modeling and deformation of three-dimensional objects. We approximate the deformable parts of an object using sweep surfaces. The vertices on the object boundary are bound to the sweep surfaces and then follow their deformation. For practical applications, we apply this approach to 3D human body modeling and deformation, and then extend it to the freeform deformation and to the elastic deformation of three-dimensional objects. For human modeling and deformation, a simple skeleton structure is extracted from user-specified feature points; after that, control sweep surfaces that approximate human arms, legs and torso are automatically generated. The vertices on the model are bound to nearby sweep surfaces and follow the deformation of the sweep surfaces as the model bends and twists its arms, legs, spine and neck. Anatomical features including bone-protrusion, muscle-bulge, and skin-folding are also supported. We then extend the sweep-based approach to the freeform deformation of threedimensional objects. The user selects deformable parts of an object and the corresponding control sweep surfaces are generated by interpolating key cross-sections. The user can deform the shape of an object by controlling the underlying sweep surfaces. Several sweep surfaces of deformable parts can be organized into a hierarchy so that they interact with each other in a controlled manner. The sweep-based freeform deformation technique also provides various important advantages, including volume