J. Wilhelms and A. Van Gelder. Anatomically based modeling. In Computer Graphics (SIGGRAPH '97 Proceedings), pages 173--180, August 1997.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....such as rapid computing speed, easy control. Thereby, as a complicated object, muscle layer is commonly constructed based on geometry in the layered body modeling systems. Present geometrical muscle models are often too simple to simulate 3D forms of muscles, such as the model proposed by Wilhelms[11]. His model is composed of three spheroids (one for muscle body, the other two are tendons of the muscle) He updated the muscles as deformable discrete cylinders in the latter work. These coarse polygons only simulate restricted shapes of the muscles. LEMAN[21] developed by Turner uses implicit ....

Jane Wilhelms and Van Gelder, A. "Anatomically Based Modeling", Computer Graphics (ACM Siggraph Proceedings), p. 173-180, August 1997.

....and muscles, soft tissues and skin. In the work mentioned above, muscles are made of combinations of three ellipsoids (two tendons and one muscle between) More recently, this work was extended and now, in her anatomically based model, muscles are represented by deformable discretized cylinders [38]. Turner has developed the LEMAN system [35] to construct and animate 3D characters based on the elastic surface layer model. Muscles are modeled as deformable implicit surfaces (currently spheres, cylinders and superellipses) The muscle layer has been represented by deformable geometrical ....

Wilhelms, J. and Van Gelder, A. "Anatomically Based Modeling", Computer Graphics Proceedings, Annual Conference Series, 1997.

....techniques were applied to anatomically based models of humans and animals. Scheepers et al. 14] have presented a model where muscles (represented by deformable ellipsoids) react automatically to changes in the posture of the articulated skeleton and influence on the surface form. Wilhelms [20] proposes a multi layered anatomically based model to simulate animals. In her model, muscles are represented by deformable discretized cylinders. 3. The skeleton Human body can be defined briefly as a conglomerate of skeleton, muscles, fat and skin. The skeleton is formed by bones (about 206 in ....

Wilhelms, J. and Van Gelder, A. "Anatomically Based Modeling", In: Computer Graphics Proceedings, p. 173180, 1997.

....is simulated by binding the degrees of freedom (scaling and possibly translation and or rotation) of each ellipsoid to the degrees of freedom of the underlying skeleton joints. Despite its simplicity and attractiveness, the ellipsoid model cannot capture most muscle shapes. In more recent work [Wilhelms97b], Whilhelms et al. use a generalised cylinder made up of a certain number of cross sections that consist in turn of a fixed number of vertices. Volume variation of the muscle during deformation is reduced by scaling each crosssection so as to preserve its area. Similarly, Scheepers and his ....

J. Wilhelms, A. Van Gelder, "Anatomically Based Modeling", Computer Graphics (SIGGRAPH '97 Proceedings), pp. 173-180.

....easily observed in thick, long hair. Key Words: hair, collision detection and response, layered models, physically based animation, natural phenomena 1. INTRODUCTION Impressive advances have been achieved in modelling and animating virtual creatures within the past few years (see for instance [30, 5, 14, 13]) These techniques cover mod1 current affiliation: discreet a joint research project of CNRS INRIA UJF INPG, INRIA Rhne Alpes, ZIRST, 655 avenue de l Europe, Montbonnot, 38334 Saint Ismier Cedex, France elling the creature s body, clothes, motion, and behavior. Meanwhile, hair animation ....

J. Wilhelms and A. Van Gelder. Anatomically based modeling. Proceedings of SIGGRAPH 97, pages 173-- 180, August 1997.

.... of pioneering work on deformation [25, 28, 15, 1] there continue to be exciting new applications [18, 17] and improvements in simulation e#ciency [2, 6] Numerous examples of human body modeling exist in the literature with particular areas of interest being deformations of skin and muscles [27, 9], faces [12] and layered models [5] Support exists in commercial animation packages, such as Maya, for simulating tissue dynamics. There have also been significant recent developments for interactive dynamic tissue simulation, especially for force feedback applications such as surgical ....

J. Wilhelms and A.V. Gelder. Anatomically Based Modeling. In SIGGRAPH 97 Conference Proceedings, pages 173--180, 1997.

....earth. In general, the art of graphical human forms is advanced enough to create the sorts of models described in Snow Crash, because such detail can be designed off line and then displayed during live interactions. Body, face, skin, and muscle models have been created by many groups, including [32, 21, 4, 54, 60, 13]. 2.2. Clothing and Attachments Though it is not required, most avatars in the Metaverse don some sort of clothing. A black and white s clothing emulates what the user is wearing in reality. It appears that the clothing for a rendered avatar is created when the avatar is created and does not ....

J. Wilhelms and A. V. Gelder. Anatomically based modeling. In SIGGRAPH '97 Proceedings, pages 173--180, Aug. 1997.

....user must instruct the system how to handle every new contact scenario. 2.2. Simulation of physical laws To overcome the drawbacks of kinematic methods, many techniques employ the notion of force and energy [14, 21] Wilhelms et al. simulate a sliding skin layer by relaxation of a spring mesh [39]. The relaxation scheme does not account for buckling, hence realistic folding does not occur. Accurate physical simulation, which has been studied in computational mechanics, can provide a powerful tool for automatically generating realistic deformations. They have been traditionally very ....

Wilhelms, J., and Van Gelder, A., Anatomically based modeling. Proceedings of SIGGRAPH 97, Computer Graphics Proceedings, Annual Conference Series, 1997, pp. 173-180.

....simulated by binding the degrees of freedom (scaling and possibly translation 1 and or rotation) of each ellipsoid to the degrees of freedom of the underlying skeleton joints. Despite its simplicity and attractiveness, the ellipsoid model cannot capture most muscle shapes. In a more recent work [20], Whilhelms et al. use a generalized cylinder made up of a certain number of cross sections that consist in turn of a fixed number of vertices. Volume variation of the muscle during deformation is reduced by scaling each cross section so as to preserve its area. Similarly, Scheepers and his ....

J. Wilhelms, A. Van Gelder. Anatomically Based Modeling. ACM Computer Graphics (Proc. of SIGGRAPH '97), 173-180, 1997. 7

....and add support for these two bones in the model and interface. The next major improvement for this model would then be to transform the palm and fingers into deformable surfaces and to model the underlying bones and musculature of the hand to give it a far more realistic appearance as in [Wilhe97], Gourr89] and [Schee97] ....

Wilhelms, J, Van Gelder, A: Anatomically Based Modeling, Proc. SIGGRAPH '97, 173-180

....Gooch used complementary colors to provide additional depth cues [20, 10, 11] Finally, modeling is a critical aspect of depicting the human form. In the absence of a good model, any attempt at rendering skin will fail to satisfy. There has been some research in the area of modeling human figures [23, 5]. In our work, we have not considered modeling issues, relying instead on a Digibot scan of Michelangelo s David and a female model by Louise Bell. 3 Artistic Principles in Portraiture In his book, The Technique of Portrait Painting [19] classical portrait painter Harrington Mann emphasizes ....

Jane Wilhelms and Allen Van Gelder. Anatomically based modeling. SIGGRAPH 97 Conference Proceedings, 1997.

....happens in areas with an important mobility e.g. the shoulder. Thus, the crease of the armpit often looks unrealistic. More recent work aims at mimicking more closely the actual anatomy of humans or animals. Whilehms developed an interactive tool for designing and animating monkeys and cats [Wilhelms97] In her system, ellipsoids or triangular meshes represent bones and muscle. Each muscle is a generalised cylinder made up of a certain number of cross sections that consist in turn of a certain number of points. The muscles show a relative incompressibility when deformed. A voxelisation is used ....

....empty spaces left by organs and missing muscles. An implicit surface, corresponding to the corch 1 , is created from all the geometric primitives. 3. A fat layer with a viscoelastic behaviour. 4. A skin represented by a geometric mesh or spline patches. Unlike other approaches [Turner93, Wilhelms97] our skin is not an elastic surface. This permits to use very fine geometry e.g. laser scans without slowing down the simulation. As the skin is moreover anchored to the fat layer, it does move elastically. Though this is unacceptable from a biomechanical standpoint, it is justified for our ....

J. Wilhelms, A. Van Gelder, "Anatomically Based Modeling", Computer Graphics (SIGGRAPH '97 Proceedings), pp. 173-180.

....muscles using spring mesh dynamics; a modeled skin cross section is reshaped by a ray casting procedure that finds the maximum displacement of the underlying tissue. Several papers by Wilhelms and coworkers have shown anatomically representative human and animal models. In Wilhelms and Van Gelder [36] several classes of muscles are algorithmically modeled with attention to volume conservation; skin is a spring mesh anchored to underlying tissue or bone in appropriate areas. Scheepers et al. 31] produced convincing representations of muscles as well as preliminary but promising skin ....

J. Wilhelms and A. Van Gelder, Anatomically Based Modeling. Proc. SIGGRAPH 97, pp. 173-180.

....layering. We believe that other types of bodily animation, such as hair fur movement and bodily muscular deformation can be best generated by other techniques. Animating these elements is a rich topic of research; some of the interesting approaches have utilized physical simulation [Anjyo 1992, Wilhelms 1997, Van Gelder 1997] and some animator visual programming to build deformation functions directly into the character s skin mesh [Hash 1999] 194 9.3.2 Better Auto Keying and Tweaking Controls Our current auto keying approach to placing tweaks, in which the effects of a tweak are bounded by ....

Jane Wilhelms and Allen Van Gelder. Anatomically Based Modeling, Proceedings of SIGGRAPH 97, Computer Graphics Proceedings, Annual Conference Series, pp. 173-180 (August 1997, Los Angeles, California). Addison-Wesley. Edited by Turner Whitted.

....component in physician and paramedical personnel training, pretreatment planning, instrument device design and the evaluation and approval process. Nowadays, teleimaging, simulations, image guided robotassisted therapies [8, 3] and several methods to model human gures (including bones and muscles) [9, 10] are widely investigated. But, up to our knowledge, no tool has been proposed to biomechanicians in order to experiment their ideas of motion control strategies. We have dened an open platform in order to experiment motion control strategies on a virtual human body (see gure 1) First, medics and ....

J. Wilhelms and A.V. Gelder. Anatomically based modeling. In Proceedings of the ACM SIGGRAPH, 1997.

....the skeleton results automatically in corresponding articulation of the original model. 2 Related Work Springs and Bones. Koch et al. KGC 96] use data from CT and range scans to construct a bone structure, onto which they connect a skin mesh using a set of springs. Wilhelms and Van Gelder [WV97] use existing bone models, and a simple model of the underlying muscles to determine the changes in muscle shape. In both methods the skin is a triangular mesh with springs at edges, is connected via a spring network and is relatively close to the underlying simulated muscles or bone. The springs ....

....the skin is a triangular mesh with springs at edges, is connected via a spring network and is relatively close to the underlying simulated muscles or bone. The springs are generated by locating one (or several in [KGC 96] points close to the mesh vertices on the underlying structure. In [WV97] a parameterization of the muscles is used to create such attachment points. In [LTW95] a scanned facial model is animated via a spring network which includes an estimated underlying skull, and a layer of springs representing simulated muscles. A method for more precise modeling of muscles ....

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Jane Wilhelms and Allen Van Gelder. Anatomically based modeling. In Turner Whitted, editor, SIGGRAPH 97 Conference Proceedings, Annual Conference Series, pages 173-- 180. ACM SIGGRAPH, Addison Wesley, August 1997. ISBN 0-89791-896-7.

....values in this table, and using them as barycentric coordinates for the triangle being drawn. Because we start at the beginning of the table each time the animal is redrawn, we generate the same hairs each time. Skin motion during animation uses an anatomically based method described elsewhere [16, 17]. Each vertex of the skin s triangle mesh is transformed to its present position. Although triangles shift and may change shape as a result, the hairs locations, being retained in barycentric coordinates, can be efficiently recalculated. Associated with each skin vertex is a normal vector, which ....

Jane Wilhelms and Allen Van Gelder. Anatomically based modeling. In Computer Graphics (ACM SIGGRAPH Proceedings), Aug. 1997.

....to new positions; 3) map skin vertices back to world space; 4) apply iterative relaxation algorithm, adjusting skin vertices to achieve equilibrium of the elastic membrane forces. Table 2 shows performance times for these steps. A longer version of this paper is available as a technical report [20]. Examples from our work on anatomically based modeling can be found on our web site www:cse:ucsc:edu=#wilhelms=fauna. 2 BACKGROUND AND RELATED WORK Blinn s seminal work on implicit surface modeling included a blobby man made by extracting a surface from around an articulated skeleton [1] ....

Jane Wilhelms and Allen Van Gelder. Anatomically Based Modeling. Technical Report UCSC-CRL-97-10, CS Dept., University of California, 225 A.S., Santa Cruz, CA 95064, April 1997.

....of animation of living beings are becoming quite important in the fields of medicine, surgical procedures, biomechanics, ergonomics, and the like. Recent research in human modeling and animation has turned towards anatomically based methods, using underlying tissues to generate the surface shape [21, 28, 29]. Another class of approaches has attempted to deform an a priori defined surface model of the being, using ad hoc techniques to relate changes in joint angles segment positions to changes in the skin [9, 15, 17, 18] We present a hybrid modeling and animation approach that combines the ....

....fits within the surface model, 4) design individual muscles, bones, and generalized tissues to approximately fit within the skin, and (5) attach skin vertices to the nearest underlying tissue. Once the animal model has been defined and the skin attached, animation is accomplished as described in [28, 29]. Examples from our work on anatomically based modeling can be found on our web site: www:cse:ucsc:edu= wilhelms=fauna. 2. Background and Related Work From the early days of robotics and animation research, robots, humans, animals and other articulated bodies have been represented using a ....

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J. Wilhelms and A. V. Gelder. Anatomically based modeling. In Computer Graphics, pages 173--180, Los Angeles, Ca., August 1997. ACM Siggraph Conference Proceedings.

....based model is described in Section 3. Technical details of muscles and skin are discussed in Section 4 and Section 5. Results are evaluated in Section 6, and future work is discussed in Section 7. Conclusions are drawn in Section 8. A shortened version of this paper has been published [WVG97] Examples from our work on anatomically based modeling can be found on our web site www:cse:ucsc:edu= wilhelms=fauna. 2 Background and Related Work Human and animal models of considerable complexity are being produced, but rarely would one confuse them with the real thing. In most cases, ....

Jane Wilhelms and Allen Van Gelder. Anatomically based modeling. In Computer Graphics (ACM SIGGRAPH Proceedings), Aug. 1997.

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J. Wilhelms and A. Van Gelder. Anatomically based modeling. In Computer Graphics (SIGGRAPH '97 Proceedings), pages 173--180, August 1997.

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WILHELMS, J., AND VAN GELDER, A. 1997. Anatomically Based Modeling. In SIGGRAPH 97 Conference Proceedings, Addison Wesley, vol. 31 of Annual Conference Series, ACM SIGGRAPH, 173--180.

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J. Wilhelms and A. V. Gelder. "Anatomically based modeling", in Computer Graphics, pages 173-180, Los Angeles, Ca., August 1997, ACM Siggraph Conference Proceedings.

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Jane Wilhelms and Allen Van Gelder. Anatomically based modeling. Proceedings of SIGGRAPH 97, pages 173--180, August 1997. ISBN 0-89791896 -7. Held in Los Angeles, California.

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J. Wilhelms and A. Van Gelder. Anatomically based modeling. In Computer Graphics (SIGGRAPH '97 Proceedings), pages 173--180, August 1997.

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J. Wilhelms and A. Van Gelder. Anatomically based modeling. Comput. Graph. (SIGGRAPH Proc.), pages 173--180, 1997. The Eurographics Association 2003.

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J. Wilhelms and A. Van Gelder. Anatomically Based Modeling. Computer Graphics, 173--180, 1997.

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J. Wilhelms and A. Van Gelder. Anatomically Based Modeling. In Turner Whitted, editor, Computer Graphics (SIGGRAPH '97 Conf. Proc.), pages 173--180. ACM SIGGRAPH, August 1997.

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J. Wilhelms and A. Van Gelder. Anatomically Based Modeling. In Computer Graphics (SIGGRAPH '97 Conf. Proc.), pages 173--180, August 1997.

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J. Wilhelms and A. Van Gelder. Anatomically Based Modeling. In Computer Graphics (SIGGRAPH '97 Conf. Proc.), pages 173--180, August 1997.

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WILHELMS J., GELDER A. V.: Anatomically based modeling. Proceedings of SIGGRAPH 1997 (1997), 173--180. 2

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J. Wilhelms and A. Van Gelder. Anatomically based modeling. Comput. Graph. (SIGGRAPH Proc.), pages 173--180, 1997.

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Wilhelms, J. and Van Gelder, A.: Anatomically Based Modeling, Computer Graphics (SIGGRAPH '97 Proceedings) , pp. 173-180, 1997.

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Wilhelms, J. and Van Gelder, A. (1997) "Anatomically Based Modeling", In: Computer Graphics Proceedings, p. 173-180.

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