Eric Landreneau

Abstract: We present a method for generating scales and scale-like structures on a polygonal mesh through surface replacement. As input, we require a triangular mesh that will be covered with scales and one or more proxy-models to be used as the scale’s shape. A user begins scale generation by drawing a lateral line on the model to control the distribution and orientation of scales on the surface. We then create a vector field over the surface to control an anisotropic Voronoi tessellation, which represents the region occupied by each scale. Next we replace these regions by cutting the proxy model to match the boundary of the Voronoi region and deform the cut model onto the surface. The result is a fully connected 2-manifold that is suitable for subsequent post-processing applications like surface subdivision.

Abstract: While animation using barycentric coordinates or other automatic weight assignment methods has become a popular method for shape deformation, the global nature of the weights limits their use for real-time applications. We present a method that reduces the number of control points influencing a vertex to a user-specified number such that the deformations created by the reduced weight set resemble that of the original deformation. To do so we show how to set up a Poisson minimization problem to solve for a reduced weight set and illustrate its advantages over other weight reduction methods. Not only does weight reduction lower the amount of storage space necessary to deform these models but also allows GPU acceleration of the resulting deformations. Our experiments show that we can achieve a factor of 100 increase in speed over CPU deformations using the full weight set, which makes real-time deformations of large models possible.

Abstract: We present a method for simplifying a polygonal character with an associated skeletal deformation such that the simplified character approximates the original shape well when deformed. As input, we require a set of example poses that are representative of the types of deformations the character undergoes and we produce a multi-resolution hierarchy for the simplified character where all simplified vertices also have associated skin weights. We create this hierarchy by minimizing an error metric for a simplified set of vertices and their skin weights, and we show that this quartic error metric can be effectively minimized using alternating quadratic minimization for the vertices and weights separately. To enable efficient GPU accelerated deformations of the simplified character, we also provide a method that guarantees the maximum number of bone weights per simplified vertex is less than a user specified threshold at all levels of the hierarchy.