Study On Interactive Manipulation Of 3D Model

Based on control handles manipulated by users directly, interactive 3D model manipulation can create smooth and realistic deformation results. This technique is widely used in virtual reality, computer animation, medical image processing and movie & TV fields.A 3D geometric solid deformation technique is studied. Deformations of local tapering, twisting and bending are implemented via applying hierarchy partition and deformation operation to 3D solids. Based on hierarchical operation, 3D solid deformation technique can control 3D solid's deformation precisely. It can also obtain complex 3D deformation results using combination of operators.A mesh simplification algorithm to 3D model is studied by defining edge collapse cost of directed edge as a product of edge's length and its starting vertex's importance. This algorithm can simplify complex 3D model with abundant vertices effectively and generate a reduced mesh.Based on edge collapse mesh simplification, an interactive and fast 3D shape deformation algorithm is studied. Using edge collapse mesh simplification to extract key feature points from original model, 3D reduced mesh can be generated. Then positional constraints are added to 3D reduced mesh interactively and affine transformation is supposed for each node in the reduced mesh. Through solving a nonlinear optimization problem, optimal solutions are found for all affine transformations to get the node mapping in original model. Edge collapse mesh simplification can be effectively used to reduce the number of polygon in 3D model, and combining with nonlinear optimization solution, a real-time display and detail preserved 3D shape deformation can be realized interactively.A system of 3D model deformation has been exploited with the above mentioned methods. It can realize 3D solid's deformation based on hierarchical operation and 3D shape deformation based on edge collapse mesh simplification, respectively. Using MFC framework on VC++ platform, the system has visual operation interface and makes the operation convenient for users.