Controlled blending in contact situations

Interactive implicit modelling with complex skeletons was improved with the introduction of primitives defined at different LODs. These implicit primitives use a subdivision curve as a skeleton. In this paper an extension to this representation is presented, in order to make it suitable for the interactive modelling and animation of soft objects in contact situations. The first contribution improves the display method for subdivision-based implicit primitives; this uses an adaptive polygonisation which locally refines, where necessary, according to the currently selected LOD. The second contribution consists of a new method for preventing unwanted blending when a skeleton-curve folds back onto itself. The third introduces local deformations where surfaces that should not blend come into contact. We illustrate the benefits of this methodology by describing two applications: the interactive modelling of complex organic shapes in contact situations and the physically-based animation of such organic shapes