A linear blending scheme for rigid and non-rigid deformations

Linear blending techniques based on generalized barycentric cordinates have been well recognized in a digital production workplace for shape deformation due to its simplicity. However, the dense weights, non-rigid deformations and the lack of an intuitive control interface limit its practical use. In this paper we present a novel linear blending scheme utilizing existing barycentric coordinates to overcome these difficulties. The scheme enables cage vertices associated with sparse weights to be inferred automatically by a user's manipulation on constrained vertices or handles in real-time. For this scheme, we have developed two new techniques. The first one is a weight reduction technique to reduce the number of control points on the cage, while still keeping the surface quality. Another technique computes positions of the cage vertices, in order to preserve the rigidity of the shape by minimizing nonlinear rigidity energies. Our prototype system demonstrates that our linear blending scheme can deal with rigid and non-rigid deformation more consistently and efficiently than previous approaches.