A hybrid models deformation tool for free-form shapes manipulation

This paper addresses the way non-manifold models mixing various types of geometric representations(e.g.NURBS curves and patches, polylines, meshes), potentially immersed in spaces of different dimensions(e.g.NURBS patch and its 2D trimming lines), can be deformed simultaneously.The application domains range from the simple deformation of a set of NURBS curves in a 2D sketcher to the simultaneous deformation of meshes, patches as well as trimming lines lying in parametric spaces.~The deformation itself results from the resolution of an optimisation problem defined by a set of geometric constraints and deformation behaviours.~This new breakthrough on how CAD models can be manipulated has been made possible thanks to our linear mechanical model of deformation that can be coupled to manifolds of dimension zero(e.g.points, vertices) and one(e.g.edges, segments) whatever the spaces dimension.~An extended constraints toolbox is also proposed and enables the specification of both characteristic points/curves and continuity conditions between the various geometric models.The link between the semantic of the deformation behaviours and the geometric models is ensured through the use of multiple minimisations.The approach is illustrated with several examples coming from our prototype software.