Mathieu Desbrun and Marie-Paule Gascuel. Animating soft substances with implicit surfaces. In SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 287--290. ACM SIGGRAPH, Addison Wesley, August 1995. Los Angeles, CA.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....because the operations affect every point in space on the isosurface, inside, and outside. Shape morphing can be performed simply by interpolating between two implicit functions, and the two shapes can be of arbitrary manifold topology [1] 2] 3] Implicit surfaces can collide and deform [4], 5] the resulting fusions and separations are handled automatically. Often, in graphics, implicit functions are created by summing many infinitely differentiable functions, yielding surfaces that are smooth and seamless. The forms that they can represent are useful for modeling organic shapes ....

M. Desbrun and M.-P. Gascuel, "Animating Soft Substances with Implicit Surfaces," Proc. SIGGRAPH '95, pp. 287-290, 1995.

....update their structures and properties in real time. Several different approaches have been developed to achieve this efficiency for molecular surface computations [13, 14, 41 43, 45, 46] Other work on surface representations features the use of metaballs, molecular surfaces, and blobby models [1, 9, 17, 28, 29, 31, 36 38, 48 51]. In this paper we extend this work by describing algorithms that dynamically update and render exact smooth trimmed NURBS (non uniform rational B splines) representations for growing the molecular surfaces. Trimmed NURBS are an industry wide CAD CAGD standard and fast becoming optimized for ....

Mathieu Desbrun and Marie-Paule Gascuel. Animating soft substances with implicit surfaces. In Robert Cook, editor, SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 287--290, Los Angeles, August 1995. Addison Wesley.

....surfaces like metaballs [21] blobs [4] convolution surfaces [5] or soft objects [39] have received increasing attention in Computer Graphics. Nowadays, an important trend in representation of deformable objects is the use of implicit surfaces mixed with particle systems, as we can see in [11]. Physically based models are well suited to provide natural motion for flexible objects. One of the first physically based models was developed by Weil and used to simulate cloth by interpolating the surfaces between catenary curves [36] Barr, Terzopoulos, Platt and Fleisher have used discrete ....

Desbrun, M. and Gascuel, M. -P. "Animating Soft Substances with Implicit Surfaces", Computer Graphics, Los Angeles, California, ACM SIGGRAPH, 1995.

....are based on implicit and parametric surfaces [44] Blending of polyhedral surfaces is described in [45] and [35] These techniques, however, compute blend surfaces using energy minimization schemes that are too expensive for interactive modeling. Blobby Object Modeling Blobby objects [48] 47][10] are objects represented by scalar fields and their surfaces are iso surfaces at a predefined field value, sb. A point is considered to be inside a blobby object if its field value is above sb and outside a blobby object if its field value is below s, Smoothly varying field functions that decay ....

Desbrun, M. and Gascuel, M.-P., "Animating Soft Substances with Implicit Sur- faces", Proceedings of SIGGRAPH '95, pp. 287-290 (1995).

....soft geometry offers no easy way for computing the volume embedded inside the implicit surface. Moreover, when an animation is defined by moving some of the primitives around, volume variations should be corrected where the shape of the object is actually changing. The solution proposed [10, 7] relies on the notion of territories associated with each implicit primitive. The territory of a primitive is the region of the implicit volume where the field generated by this specific primitive is the higher than any of the others. During an animation, a sampling of territories is maintained ....

....particle system [29] Contrary to the last case, using parametric surfaces for coating the flow would be almost impossible, since large deformations, and possibly separations into several disconnected components are to be generated. Implicit surfaces, that were already used for rendering particles [10], thus seem the right solution. However, the answer is not so straightforwards considering that several thousands of particles are to be animated, and that a texture should be coherently attached to the flow in order to render lava crust. The solution developed in [29] tackles the number of ....

M. Desbrun and M.P. Gascuel. Animating soft substances with implicit surfaces. In SIGGRAPH'95 Conference Proceedings, Annual Conference Series, pages 287--290. ACM SIGGRAPH, Addison Wesley, August 1995. Los Angeles, CA.

....defined by the set of points of E for which f(p) C (where C is a pre chosen value in ]0, 1[ A wide variety of primitives are available [7, 20] and the blend is automatically computed by summing the potential of the primitives. Many di#erent blending functions [21, 22] and blending models [23, 24] have been proposed to control the smoothness of the transition region, but the operators remain limited to the blending and the control of which primitives must and must not blend. The locality of the definition and the capacity to be automatically blended allow modeling techniques based on these ....

M. Desbrun and M.P. Gascuel. Animating Soft Substances with Implicit Surfaces. Computer Graphics (Proc. of SIGGRAPH 1995.

....fonction potentiel, axe mdian, squelette, polyboule, modle dformable. RCFAO 16 2001. Tridimensional reconstruction, pages 203 212 1. Introduction The use of implicit surfaces has been increasing over the last few years, especially in the fields of object modeling and animation [DES 95, BLO 97] However, few studies have been made concerning reconstruction by skeleton and potential function, based on digital volumes or samples of points. FER 96, GUI 00b] To reconstruct an object from a sample of points, the rule here is to generate an implicit surface from potential sources: ....

DESBRUN M., GASCUEL M.-P., "Animating soft substances with implicit surfaces ", SIGGRAPH'95 Proceedings, 1995, p. 287-290.

....by the collisions with the balls, an assumption that clearly holds. Figure 6: The reconstructed model of the lottery machine. Using a grid of 250x250x250 in a bounding box of 100x100x100 inch 4 Conclusions The idea of using implicit surfaces for collisions detection is well known, cf. [5, 4]. However, a major problem of this approach has been that only a very restricted ( blobby ) class of objects could be modeled. Using the approach of this paper, arbitrary surface representations of (dynamic) objects can be very well approximated as a potential funcion. Since the evaluation of the ....

Mathieu Desbrun and Marie-Paule Gascuel. Animating soft substances with implicit surfaces. In SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 287--290, Los Angeles, CA, USA, August 1995. ACM SIGGRAPH.

.... the movements of the objects should conform to the common sense of the viewer and to the physical laws, computations should be fast enough to meet the demand of real time animation for as many animated scenes as possible. There are many methods used for animating the behaviour of a liquid [Reeve83a, Kass90a, Szeli92a, Desbr95a, OBrie95a, Witki94a]. Most of them are suitable for situations where the uid is the only object of an animated scene. In this paper we concentrate on the scenes in which solids and a liquid medium are present. From the computational point of view the solid bodies are very di erent from the liquid ones. It is hard ....

Desbrun, M., Gascuel, M.-P. Animating Soft Substances with Implicit Surfaces. SIGGRAPH'95 Conference Proceedings, 1995

....the implicit functions that make up each individual blob. As blobs approach each other they tend to blend together. This phenomenon may not be desirable in some situations and can be avoided by using a special type of blending graph that stores which blobs are permitted to blend together [WW89, DG95] Geoff and Brian Wyvill are particularly prolific researchers in the implicit surface and blobby modeling areas. They have published work on animating implicit surfaces [WMW86b, WMW86a, WW86] texturing soft objects [WWM87] and ray tracing implicit models [WT90] Brian Wyvill s recent work ....

M. Desbrun and M. Gascuel. Animating soft substances with implicit surfaces. In Computer Graphics (SIGGRAPH 95 Proceedings), pages 287--290, August 1995.

....the animation proceeds, ellipsoids are automatically moved and reshaped without any other user intervention. We calcu late the lengths of the three axes to preserve the volume of the individual ellipsoids at each frame. Nevertheless, the final volume might vary due to the blending operations. In [6] local volume variations are corrected but were not implemented for this research. Blending groups (of ellipsoids) and the following steps avoid unwanted joining of nearby members: # To calculate the value of the scalar field at a point #x; y; z#: Compute the sum of all the ellipsoids in ....

M. Desbrun and M.-P. Gascuel. Animating soft substances with implicit surfaces. Computer Graphics (SIGGRAPH '95 Proceedings), 29:287--290, August 1995.

....The pinball method [BN91, BY92] uses sphere trees to quickly reject the particles not intersecting the surface, but also requires a large number of spheres to achieve desired accuracy. Precise contact modeling between flexible solids using implicit functions has been described in [Gas93, DG95] Its applications, however, are limited to scenarios where objects can be represented as specific types of implicit functions. 2.3 Numerical Methods Explicit integration techniques (e.g. ZC99] are often used in dynamic simulation of deformable objects. They are usually fast, but suffer from ....

Mathieu Desbrun and Marie-Paule Gascuel. Animating soft substances with implicit surfaces. SIGGRAPH 95 Conference Proceedings, pages 287--290, 1995.

.... and their collision responses, which are deformations of implicitly defined solids, are formulated as an additional term in the field functions for the implicitly defined solid based on techniques by [3, 4] Using these formulations, techniques for animating very soft substances are introduced[7, 6]. They use particle system for large scale deformations computing interaction between particles and the union of viscoelastic layer over particles defines the soft substances. Like other particle based models, they model viscoelasticity, fusion and separation by interaction between particles and ....

....different formulation of collision detections and responses which based on collision history. This presentation addresses this problem and raises needs for new model of collision detection and its responses based on collision history by extending implicit surface technique. Our method is based on [6] and suggests that the collision trace of gluey liquids should be stored as a curve and the implicit deformation of each particle be done with the trace curve using techniques in [4] 2 Overview Particle systems[12, 13] can be used to simulate a wide range of interesting behaviors. Particles are ....

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Mathieu Desbrun and Marie-Paul Gascuel. Animating soft substances with implicit surfaces. Computer Graphics (ACM SIGGRAPH Proceedings), pages 287--290, August 1995.

....When the value becomes less than the Iso value, we stop the seed migration. This allows seeds to move to the surface. Because in general the surface does not undergo large differences from frame to frame this allows us to have a good approximation for the next instance. Figure 2 Seed Migration Desbrun et al. [1995] ordered the seeds to produce a set of polygons that fit the surface at run time. Due to the nature of the fixed axis it is simply necessary to run through the set of polygons to display the surface at any time. The vertices of the polygons simply correspond to the seed positions. We have chosen ....

....be preserved. Controlling the volume of an object during animation can often be very important, as the eye can be quite keen at sensing volume discrepancies. 3.1 Volume Preservation In previous methods, attempts were made to keep the volume constant under blending of more than one primitive. In Desbrun et al. [1995] local volume variation was considered by creating territories forming tetrahedral pyramids from the seeds. These were then used to create a translation that was combined with the field function to reduce the field strength of the primitive reducing volume. This idea was extended by changing the ....

[Article contains additional citation context not shown here]

Desbrun M and Gascuel M-P (1995) Animating soft substances with implicit surfaces. Computer Graphics, 1995. Proceedings SIGGRAPH'95.

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Mathieu Desbrun and Marie-Paule Gascuel. Animating soft substances with implicit surfaces. In SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 287--290. ACM SIGGRAPH, Addison Wesley, August 1995. Los Angeles, CA.

....that consist in discretizing space into voxels and then computing what flows in and out each voxel [9] would not be convenient here, since interactions with obstacles which are not necessarily aligned with voxels need to be computed. Physically based particle systems, such as those used in [15, 19, 20, 14, 7] seem a better approach for our case. Our approach relies on the smoothed particles model introduced in [4] The main feature of smoothed particles is to model materials governed by a macroscopic state equation. It defines the global behavior of the material independently of the sampling rate. ....

Mathieu Desbrun and Marie-Paule Gascuel. Animating soft substances with implicit surfaces. In SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 287--290. ACM SIGGRAPH, Addison Wesley, August 1995. Los Angeles, CA.

....du volume A partir de cette approximation du volume, on peut gerer les variations de volume de chaque squelette grace a un controleur Proportionnel Derive. On peut en e#et changer la fonction d enrobage de chaque primitive de facon a equilibrer les variations observees lors de l echantillonnage [DG95] Pour ne pas modifier les parametres physiques de notre objet qui sont stockes dans les variations de la fonction potentiel f , on agira sur l enrobage par une simple translation de f . Ainsi, en cas de baisse de volume, on translatera f vers la droite de facon a augmenter l epaisseur ....

Mathieu Desbrun and Marie-Paule Gascuel. Animating soft substances with implicit surfaces. Computer Graphics, August 1995. Proceedings of SIGGRAPH'95 (Los Angeles, CA).

.... [TPF89, LJR 91, Ton91, LHVD95] Di#erentes techniques peuvent etre utilisees pour remplacer l a#chage d un ensemble de spheres par un rendu visuel de qualite [Hab97] Dans le cadre de l animation de substances allant de la pate a modeler aux liquides visqueux, nos modeles precedents [DG95, CGD97] utilisaient une surface implicite engendree par les particules : chacune de ces dernieres portait un potentiel decroissant avec la distance, la surface etant definie comme une isopotentielle pour la somme de ces contributions. Cependant, ce modele n etait pas entierement satisfaisant pour ....

....des proprietes de la peau Le modele de base etant defini, il est possible de l enrichir de nouvelles proprietes physiques, sans que l algorithme ne change. Ces proprietes, comme la surface ou le volume constant, etaient delicates a mettre en oeuvre dans les modeles implicites precedents [DG95] elles trouvent pourtant ici une solution simple. 5.1 Surface constante Lors de la polygonalisation, il est aise de sommer la surface de chaque triangle genere afin d obtenir une approximation de l aire totale de la surface. On peut alors, a l instar de la tension de surface, rajouter une ....

Mathieu Desbrun and Marie-Paule Gascuel. Animating soft substances with implicit surfaces. In SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 287--290. ACM SIGGRAPH, Addison Wesley, August 1995. Los Angeles, CA.

.... can be written as follows, thanks to the structure of H : F i = kdt # j (i, j) # Edges (v j v i ) The sum of the relative velocity with the neighbors has been used several times in the past as artificial viscosity to create a dissipative force in mass spring or particle systems [MP89, DG95] or in Rayleigh damping forces. It intuitively means that the motion of a mass point is influenced by the motion of its neighbors: a particle will tend to follow the local displacement. In the implicit integration, this articifial viscosity is proportional to both the time step and the stiffness ....

Mathieu Desbrun and Marie-Paule Gascuel. Animating soft substances with implicit surfaces. In SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 287--290. ACM SIGGRAPH, Addison Wesley, August 1995. Los Angeles, CA.

....1. 1 Previous approaches Particle systems were first defined in Computer Graphics as sets of moving points, without interaction between them [Ree83] More recently, particles systems have been widely used for simulating inelastic deformations and even fluids [MP89, TPF89, LJR 91, Ton91, DG95, LP95, LHVD95, GLG95] Most methods developed so far use di#erent simplified versions of the same attractionrepulsion force for modeling interactions between particles. This force derives from the Lennard Jones potential, proposed for modeling pairwise microscopic interactions between atoms in a ....

....models. A solution for computing a smooth surface from particles consists in using an iso surface of some implicit function controlled by the particles [MP89, Ton91] The resulting implicit surface can be used for collision and contact processing between the body and its environment [Gas93, DG95] However, coating particles with an arbitrary implicit function introduces large volume variations. This problem should not occur if a coherent definition of the surface can be found since particles mimic a material that is supposed to keep its volume nearly constant. 1.2 Overview This paper ....

[Article contains additional citation context not shown here]

Mathieu Desbrun and Marie-Paule Gascuel. Animating soft substances with implicit surfaces. Computer Graphics, pages 287--290, August 1995. Proceedings of SIGGRAPH'95 (Los Angeles, CA).

.... in the specific case of objects discretized into lattices of fixed topology [33] 34] We present in this section the only solution to our knowledge that has been proposed for controlling the volume of bodies that undergo large deformations and topological changes such as separation and fusion [9]. Unwanted volume variations are exacerbated in implicit surface animation. They are produced by the field blending process during the relative motion of the skeletons, and they may be particularly annoying when the object undergoes separation or fusion. Although the problem has already been ....

....Fig. 14. Collisions with the ground and intercollisions of a simple articulated implicit object falling on its side. B. Animating soft substances This section presents a quite di#erent application of the techniques we have described. The soft substance model we develop here, first introduced in [9], is particularly interesting since it benefits from the specific capability of implicit surfaces to model separation and fusion. The constant volume deformations generated by our model are very important in this case, otherwise an important increase of volume would be produced during fusion. B.1 ....

Mathieu Desbrun and Marie-Paule Gascuel. Animating soft substances with implicit surfaces. In SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 287--290. ACM SIGGRAPH, Addison Wesley, August 1995. Los Angeles, CA.

.... force F i can be written as follows, thanks to the structure of H: F i = kdt j (i, j) # Edges (v j v i ) The sum of the relative velocity with the neighbors has been used several times in the past as artificial viscosity to create a dissipative force in mass spring or particle systems [14, 4], or in Rayleigh damping forces. It intuitively means that the motion of a mass point is influenced by the motion of its neighbors: a particle will tend to follow the local displacement. In the implicit integration, this articifial viscosity is proportional to both the time step and the stiffness ....

Mathieu Desbrun and Marie-Paule Gascuel. Animating soft substances with implicit surfaces. In SIGGRAPH 95 Conference Proceedings, Annual Conference Series, pages 287--290. ACM SIGGRAPH, Addison Wesley, August 1995. Los Angeles, CA.

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M. Desbrun and Marie-Paule Gascue. Animating soft substances with implicit surfaces. Proceedings of SIGGRAPH, pages 287--290, August 1995.

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M. Desbrun and M.-P. Gascue, "Animating Soft Substances with Implicit Surfaces," Proc. SIGGRAPH, pp. 287-290, Aug. 1995.

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M. Desbrun and M-P Gascuel. Animating soft substances with implicit surfaces. In Proc. SIGGRAPH 95, pages 287#290, 1995.

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M. Desbrun and M-P. Gascuel, "Animating soft substances with implicit surfaces", Proc. SIGGRAPH'95, pp. 287-290, 1995.

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M. Desbrun, M.-P. Gascuel, "Animating soft substances with implicit surfaces", Computer Graphics (proc. SIGGRAPH), pp. 287-290, 1995.

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M. Desbrun and M. Gascuel. Animating soft substances with implicit surfaces. Computer Graphics (Proceedings SIGGRAPH'95), pages 287-290, August 1995.

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M. Desbrun and M-P. Gascuel. Animating Soft Substances with Implicit Surfaces. In SIGGRAPH '95, pages 287 # 290, Los Angeles, CA, USA, 1995.

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DESBRUN M., GASCUEL M.-P., "Animating Soft Substances with Implicit Surfaces ", Computer Graphics, , 1995, Proceedings SIGGRAPH'95.

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DESBRUN, M. and GASCUEL, M.-P., "Animating soft substances with implicit surfaces," Computer Graphics, vol. 29, no. Annual Conference Series, pp. 287--290, 1995.

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Mathieu Desbrun and Marie-Paule Gascuel. Animating soft substances with implicit surfaces. Proceedings of SIGGRAPH 95, pages 287--290, August 1995. ISBN 0-201-84776-0. Held in Los Angeles, California.

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M. Desbrun and M.-P. Gascue, "Animating Soft Substances with Implicit Surfaces," Proc. SIGGRAPH, pp. 287-290, Aug. 1995.

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M. Desbrun and M-P. Gascuel, "Animating soft substances with implicit surfaces", Proc. SIGGRAPH'95, pp. 287-290, 1995.

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Mathieu Desbrun and Marie-Paule Cani. Animating soft substances with implicit surfaces. In Computer Graphics (Siggraph proceedings), volume 29, pages 287--290, 1995.

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DESBRUN M., CANI M.-P.: Animating soft substances with implicit surfaces. In Computer Graphics Proceedings (1995), ACM SIGGRAPH, pp. 287--290. 2, 6

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M. Desbrun and M.-P. Gascuel. Animating soft substances with implicit surfaces. In Proc. SIGGRAPH 95, pages 287--290, 1995.

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M. Desbrun and M. Gascuel. Animating Soft Substances with Implicit Surfaces. pages 287--290, 1995.

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M. Desbrun and M.-P. Gascuel, "Animating soft substances with implicit surfaces," in SIGGRAPH '95 Proceedings, pp. 287--290, August 1995.

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Mathieu Desbrun and Marie-Paule Gascuel. Animating soft substances with implicit surfaces. In Computer GRAPHICS (SIGGRAPH'1995.

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M. Desbrun and M-P. Gascuel. Animating Soft Substances with Implicit Surfaces. In SIGGRAPH '95, pages 287 # 290, Los Angeles, CA, USA, 1995.

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Desbrun M., Gascuel M.-P.: Animating soft substances with implicit surfaces. In ACM SIGGRAPH Conference Proceedings, 287--290 (1995).

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DESBRUN M., CANI M.-P.: Animating soft substances with implicit surfaces. In Computer Graphics Proceedings (1995), ACM SIGGRAPH, pp. 287--290.

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M. Desbrun and M.P. Gascuel. Animating Soft Substances with Implicit Surfaces. Computer Graphics, SIGGRAPH Proceedings, pages 287--290, 1995.

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M. Desbrun and M.-P. Gascuel. Animating soft substances with implicit surfaces. In SIGGRAPH '95 Conference Proceedings, pages 287--290, Aug. 1995.

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M. Desbrun, M.-P. Gascuel, "Animating soft substances with implicit surfaces", Computer Graphics (proc. SIGGRAPH), pp. 287-290, 1995.

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M. Desbrun and M. Gascuel. Animating Soft Substances with Implicit Surfaces. SIGGRAPH, pages 287--290, 1995.

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M. Desbrun and M-P Gascuel. Animating soft substances with implicit surfaces. In Proc. SIGGRAPH 95, pages 287#290, 1995.

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M. Desbrun and M.P. Gascuel. Animating Soft Substances with Implicit Surfaces. Computer Graphics (Proc. of SIGGRAPH 1995), pp. 287--290, 1995. 2

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M. Desbrun and M.P. Gascuel. Animating Soft Substances with Implicit Surfaces. Computer Graphics (Proc. of SIGGRAPH 1995), pp. 287--290, 1995. 2

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