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Modeling: deformation tools
Ph.D. thesis

Fusion of 3D Shapes and Deformation Tools

Philippe Decaudin


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Fusion of 3D shapes and deformation tools (1994-96)

The work presented here is related to interactive geometric deformation techniques for modeling 3D objects.

Deformation techniques are often used to model the shape of geometric objects. We present a geometric deformation technique allowing local deformation of the shape of an object by merging the object with a simple 3D-shape (sphere, ellipsoid, ...). In order to deform the object, the 3D-space where it lies is continuously deformed so that the object is bumped and the shape of the bump corresponds to the simple 3D-shape. If the surfaces of both the original object and the simple shape are smooth (continuously differentiable), 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.

The interactive deformation tool based on this technique comprises a convex 3D-shape and a center (a 3D 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 parameters is particularly intuitive.

- More details in this paper.


Some illustrations :

Fusion of 3D shapes (facets description)

Fusion of a sphere and a tetrahedron

Fusion of two colored bubbles

Creation of a column in a cave

A cube becoming a star

Interactive manipulation of the deformation tool

Two kinds of effects can be obtained, the simple shape is used to produce either a bump or a dent on the object:

A box deformed by a spherical tool

Topological properties of the object are unchanged:

A torus deformed by an ellipsoidal tool

Control of the deformation :

Influence of the tool center

By applying several simple deformations to a simple 3D-object, complex objects can be created:

An ellipsoid is deformed to model a cat

Caverna Magica (computer animation):

Some images from the animation

Related publications

Ph. Decaudin. Modélisation par Fusion de Formes 3D pour la Synthèse d'Images -- Rendu de Scènes 3D imitant le Style «Dessin Animé» (Modeling using Fusion of 3D Shapes for Computer Graphics -- Cartoon-Looking Rendering of 3D Scenes). Ph.D. Thesis of Universite de Technologie de Compiegne (France), December 1996.

Ph. Decaudin. Geometric Deformation by Merging a 3D Object with a Simple Shape. In Proceedings of Graphics Interface'96, p 55--60. Toronto, Canada, May 1996.

Ph. Decaudin. Geometric Deformation by Merging a 3D Object with a Simple Shape (short version). Siggraph'95 - Technical Sketches. Los Angeles, USA, August 1995.

Ph. Decaudin, A. Gagalowicz. Fusion of 3D Shapes . In Fifth Eurographics Workshop on Animation and simulation . Oslo, Norway, September 1994.

Ph. Decaudin, A. Paouri. Caverna Magica . computer animation (~2mn). INRIA-France, 1994.


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