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112
Musculotendon Simulation for Hand Animation
- TO APPEAR IN THE ACM SIGGRAPH CONFERENCE PROCEEDINGS
"... We describe an automatic technique for generating the motion of tendons and muscles under the skin of a traditionally animated character. This is achieved by integrating the traditional animation pipeline with a novel biomechanical simulator capable of dynamic simulation with complex routing const ..."
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Cited by 51 (5 self)
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We describe an automatic technique for generating the motion of tendons and muscles under the skin of a traditionally animated character. This is achieved by integrating the traditional animation pipeline with a novel biomechanical simulator capable of dynamic simulation with complex routing constraints on muscles and tendons. We also describe an algorithm for computing the activation levels of muscles required to track the input animation. We demonstrate the results with several animations of the human hand.
An Implicit Finite Element Method for Elastic Solids in Contact
- In Comput. Anim
, 2001
"... This work focuses on the simulation of mechanical contact between nonlinearly elastic objects such as the components of the human body. The computation of the reaction forces that act on the contact surfaces (contact forces) is the key for designing a reliable contact handling algorithm. In traditio ..."
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Cited by 33 (1 self)
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This work focuses on the simulation of mechanical contact between nonlinearly elastic objects such as the components of the human body. The computation of the reaction forces that act on the contact surfaces (contact forces) is the key for designing a reliable contact handling algorithm. In traditional methods, contact forces are often defined as discontinuous functions of deformation, which leads to poor convergence characteristics. This problem becomes especially serious in areas with complicated self-contact such as skin folds.
Assisted Articulation of Closed Polygonal Models
- Proc. 9th Eurographics Workshop on Animation and Simulation
, 1998
"... Creating articulated geometric models is a common task in animation systems. In some instances, models are procedurally instanced, and articulated degrees of freedom are designed into the model. In other instances, the model is some geometric assemblage, and an articulated skeleton (sometimes called ..."
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Cited by 32 (1 self)
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Creating articulated geometric models is a common task in animation systems. In some instances, models are procedurally instanced, and articulated degrees of freedom are designed into the model. In other instances, the model is some geometric assemblage, and an articulated skeleton (sometimes called an "I-K skeleton") is bound to the model by the user, typically by manual indication of a correspondence between elements of each structure. In either case, some binding must be made to couple boundary motions to those of the skeleton; this can be done for example by generating spring networks or spatial deformation fields. Both processes can be tedious in the ordinary case, especially when the model to be articulated is given only as a boundary representation, for example a polygonal mesh representing a character's skin or clothing, or an object's surface. We present a simple method for assisted articulation of geometric models. Given a 3D polygonal mesh representing an object, an approxim...
Heads up! Biomechanical modeling and neuromuscular control of the neck
- ACM Transactions on Graphics
, 2006
"... Figure 1: Our biomechanical system comprises a skeleton, muscles, neural control system, and expressive face. 1 ..."
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Cited by 28 (8 self)
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Figure 1: Our biomechanical system comprises a skeleton, muscles, neural control system, and expressive face. 1
Comprehensive Biomechanical Modeling and Simulation of the Upper Body
"... Figure 1: The biomechanical model in action. A motion controller drives the musculoskeletal system toward a sequence of target poses. We introduce a comprehensive biomechanical model of the human upper body. Our model confronts the combined challenge of modeling and controlling more or less all of t ..."
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Cited by 28 (4 self)
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Figure 1: The biomechanical model in action. A motion controller drives the musculoskeletal system toward a sequence of target poses. We introduce a comprehensive biomechanical model of the human upper body. Our model confronts the combined challenge of modeling and controlling more or less all of the relevant articular bones and muscles, as well as simulating the physics-based deformations of the soft tissues. Its dynamic skeleton comprises 68 bones with 147 jointed degrees of freedom, including those of each vertebra and most of the ribs. To be properly actuated and controlled, the skeletal submodel requires comparable attention to detail with respect to muscle modeling. We incorporate 814 muscles, each of which is modeled as a piecewise uniaxial Hill-type force actuator. To simulate biomechanically realistic flesh deformations, we also develop a coupled finite element model with the appropriate constitutive behavior, in which are embedded the detailed 3D anatomical geometries of the hard and soft tissues. Finally, we develop an associated physics-based animation controller that computes the muscle activation signals necessary to drive the elaborate musculoskeletal system in accordance with a sequence of target poses specified by an animator.
Anatomically-Based Models for Physical and Geometrical Reconstruction of Animals
, 1998
"... This document introduces a method for modelling vertebrate animals using a combination of solid primitives for muscle, tendon and ligament tissues and a software architecture that allows these elements to be dependent on each other physically and geometrically. The title of the thesis will be: Anato ..."
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Cited by 27 (1 self)
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This document introduces a method for modelling vertebrate animals using a combination of solid primitives for muscle, tendon and ligament tissues and a software architecture that allows these elements to be dependent on each other physically and geometrically. The title of the thesis will be: Anatomically-based models for physical and geometric reconstruction of animals.
Reanimating the Dead: Reconstruction of Expressive Faces from Skull Data
, 2003
"... Facial reconstruction for postmortem identification of humans from their skeletal remains is a challenging and fascinating part of forensic art. The former look of a face can be approximated by predicting and modeling the layers of tissue on the skull. This work is as of today carried out solely by ..."
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Cited by 23 (2 self)
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Facial reconstruction for postmortem identification of humans from their skeletal remains is a challenging and fascinating part of forensic art. The former look of a face can be approximated by predicting and modeling the layers of tissue on the skull. This work is as of today carried out solely by physical sculpting with clay, where experienced artists invest up to hundreds of hours to craft a reconstructed face model. Remarkably, one of the most popular tissue reconstruction methods bears many resemblances with surface fitting techniques used in computer graphics, thus suggesting the possibility of a transfer of the manual approach to the computer. In this paper, we present a facial reconstruction approach that fits an anatomy-based virtual head model, incorporating skin and muscles, to a scanned skull using statistical data on skull / tissue relationships. The approach has many advantages over the traditional process: a reconstruction can be completed in about an hour from acquired skull data; also, variations such as a slender or a more obese build of the modeled individual are easily created. Last not least, by matching not only skin geometry but also virtual muscle layers, an animatable head model is generated that can be used to form facial expressions beyond the neutral face typically used in physical reconstructions.
Physically based rigging for deformable characters
- IN ACM SIGGRAPH/EUROGRAPHICS SYMPOSIUM ON COMPUTER ANIMATION (2005
, 2005
"... In this paper we introduce a framework for instrumenting (“rigging”) characters that are modeled as dynamic elastic bodies, so that their shapes can be controlled by an animator. Because the shape of such a character is determined by physical dynamics, the rigging system cannot simply dictate the sh ..."
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Cited by 22 (0 self)
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In this paper we introduce a framework for instrumenting (“rigging”) characters that are modeled as dynamic elastic bodies, so that their shapes can be controlled by an animator. Because the shape of such a character is determined by physical dynamics, the rigging system cannot simply dictate the shape as in traditional animation. For this reason, we introduce forces as the building blocks of rigging. Rigging forces guide the shape of the character, but are combined with other forces during simulation. Forces have other desirable features: they can be combined easily and simulated at any resolution, and since they are not tightly coupled with the surface geometry, they can be more easily transferred from one model to another. Our framework includes a new pose-dependent linearization scheme for elastic dynamics, which ensures a correspondence between forces and deformations, and at the same time produces plausible results at interactive speeds. We also introduce a novel method of handling collisions around creases.
Realistic Deformation of Human Body Shapes
- Proc. Computer Animation and Simulation 2000
, 2000
"... In this paper we propose a new, generic, multi-layered model for automating the deformations of the skin of human characters based on physiological and anatomical considerations. Muscle motion and deformation is automatically derived from an action line that is deformed using a 1D mass-spring system ..."
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Cited by 20 (2 self)
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In this paper we propose a new, generic, multi-layered model for automating the deformations of the skin of human characters based on physiological and anatomical considerations. Muscle motion and deformation is automatically derived from an action line that is deformed using a 1D mass-spring system. We cover the muscle layer with a viscoelastic fat layer that concentrates the crucial dynamics effects of the animation. We present results on a female upper torso. Keywords: skin deformation, anatomy, physiology, muscle, fatty tissues, physically-based modelling. 1
An interactive fur modeling technique
- In Proceedings of Graphics Interface
, 1997
"... A technique for modeling fur, but not long human hair, quickly, using the facilities of common graphics workstations is described. The user selects a variety of parameters to achieve the desired appearance for a particular animal, such as hair density, length, stiffness, and color properties. Underc ..."
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Cited by 20 (2 self)
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A technique for modeling fur, but not long human hair, quickly, using the facilities of common graphics workstations is described. The user selects a variety of parameters to achieve the desired appearance for a particular animal, such as hair density, length, stiffness, and color properties. Undercoat and overcoat may have separate specifications, and degrees of randomness may be specified, for added realism. Standard GL facilities are used for modeling, lighting, and rendering. Hair density is automatically adjusted for viewing distance to compensate for the limit of single pixel resolution, thus avoiding the tendency to “melt ” into a surface of uniform appearance. Gravitational effects are approximated. Four drawing methods are compared: single line, polyline, nurbs curve, and nurbs surface. The polyline method is judged to offer reasonable realism at substantially faster rendering rates than previously reported hair techniques.
