Skeletal Reconstruction of Branching Shapes

We present a new method to reconstruct an implicit representation of a branching object from a set of data points scattered on its surface. The method is based on the computation of a geometric skeleton inside the data set. This skeleton is simplified in order to filter noise and converted into skeletal elements – a graph of interconnected curves – that generate an implicit surface. We use Bézier triangles as extra skeletal elements to perform bulge free blends between branches while controlling the blend extent. The result is a smooth reconstruction of the object, that can be computed whatever its topology. The skeleton offers compact storage, and provides an underlying structure for the reconstructed object, making it easier to edit in a modeling or animation environment.     

Animation of deformable models using implicit surfaces

The paper presents a general approach for designing and animating complex deformable models with implicit surfaces. Implicit surfaces are introduced as an extra layer coating any kind of structure that moves and deforms over time. Offering a compact definition of a smooth surface around an object, they provide an efficient collision detection mechanism. The implicit layer deforms in order to generate exact contact surfaces between colliding bodies. A simple physically based model approximating elastic behavior is then used for computing collision response. The implicit formulation also eases the control of the object's volume with a new method based on local controllers. We present two different applications that illustrate the benefits of these techniques. First, the animation of simple characters made of articulated skeletons coated with implicit flesh exploits the compactness and enhanced control of the model. The second builds on the specific properties of implicit surfaces for modeling soft inelastic substances capable of separation and fusion that maintain a constant volume when animated