Geometric Deformation by Merging a D Object with a Simple Shape

Deformation techniques are often used to model the shape of geometric objects This paper presents a new geometric deformation technique allowing local deformation of the shape of an object by merging the object with a simple D shape sphere ellipsoid Two kinds of e ects can be obtained the simple shape is used to produce either a bump or a dent on the object The object is deformed so that it includes or it embeds the simple shape In order to deform the object the D space where it lies is continuously deformed so that the object is bumped and the shape of the bump corresponds to the simple D shape If the surfaces of both the original object and the simple shape are smooth continuously di erentiable the surface of the deformed object is also smooth Moreover topological properties of the object are unchanged and the volume variation of the deformed object is controlled by the volume delimited by the simple shape An interactive deformation tool based on this tech nique is presented It comprises a convex D shape and a center a D point included in the shape The user can interactively control the deformation by changing the parameters of the tool shape and the position of the tool center Control of the para meters is particularly intuitive