Skip to main content

2016 | Buch

Graphical Simulation of Deformable Models

insite
SUCHEN

Über dieses Buch

This book covers dynamic simulation of deformable objects, which is one of the most challenging tasks in computer graphics and visualization. It focuses on the simulation of deformable models with anisotropic materials, one of the less common approaches in the existing research. Both physically-based and geometrically-based approaches are examined.
The authors start with transversely isotropic materials for the simulation of deformable objects with fibrous structures. Next, they introduce a fiber-field incorporated corotational finite element model (CLFEM) that works directly with a constitutive model of transversely isotropic material. A smooth fiber-field is used to establish the local frames for each element.
To introduce deformation simulation for orthotropic materials, an orthotropic deformation controlling frame-field is conceptualized and a frame construction tool is developed for users to define the desired material properties. The orthotropic frame-field is coupled with the CLFEM model to complete an orthotropic deformable model.
Finally, the authors present an integrated real-time system for animation of skeletal characters with anisotropic tissues. To solve the problems of volume distortion and high computational costs, a strain-based PBD framework for skeletal animation is explained; natural secondary motion of soft tissues is another benefit.
The book is written for those researchers who would like to develop their own algorithms. The key mathematical and computational concepts are presented together with illustrations and working examples. It can also be used as a reference book for graduate students and senior undergraduates in the areas of computer graphics, computer animation, and virtual reality. Academics, researchers, and professionals will find this to be an exceptional resource.

Inhaltsverzeichnis

Frontmatter
Chapter 1. Introduction
Abstract
In this chapter, we introduce the objectives of dynamics simulation of deformable objects. We conduct an in-depth survey on the relevant research topics, especially the simulation of deformable models with anisotropic materials, which is less exploited in existing research. We are motivated to improve the physical realism of simulation, since many real-world objects have complex mechanical rather than isotropic properties. Both physically-based and geometrically-based approaches are studied, and our contributions are made in modeling and control of anisotropic dynamics deformations.
Jianping Cai, Feng Lin, Hock Soon Seah
Chapter 2. Mesh Representation of Deformable Models
Abstract
To prepare the ground for dynamics simulation with the Finite Element Method, we introduce a previously developed mesh representation algorithm, isosurface stuffing, which fills an object domain with a uniformly sized tetrahedral mesh. This algorithm generates tetrahedra from a small set of precomputed stencils. A variant of the algorithm creates a mesh with internal grading. That is, on the boundary where high resolution is desired, the tetrahedra elements are fine and uniformly sized; and in the interior, the tetrahedron may be coarser and vary in size.
Jianping Cai, Feng Lin, Hock Soon Seah
Chapter 3. Dynamics Simulation in a Nutshell
Abstract
In this chapter, we provide fundamental theories on continuum-based deformable models, including elasticity theory, finite element discretization, dynamics equations of motion and numerical integration schemes.
Jianping Cai, Feng Lin, Hock Soon Seah
Chapter 4. Fiber Controls in FEM Model for Transversely Isotropic Materials
Abstract
In this chapter, we investigate transversely isotropic materials for the simulation of deformable objects with fibrous structures. In previous work, direction-dependent behaviors of transversely isotropic materials can only be achieved with an additional energy function which incorporates the material preferred direction. Such an additional energy term increases the computational complexity. We introduce a fiber-field incorporated corotational finite element model (CLFEM) that works directly with a constitutive model of transversely isotropic material. A smooth fiber-field is used to establish the local frames for each element. The orientation information of each element is incorporated into the CLFEM model by adding local transformations onto each element of the stiffness matrix.
Jianping Cai, Feng Lin, Hock Soon Seah
Chapter 5. Dynamics Controls for Orthotropic Materials
Abstract
In this chapter, we further introduce deformation simulation for orthotropic materials. An orthotropic deformation controlling frame-field is conceptualized and a frame construction tool is developed for users to define the desired material properties. A quaternion Laplacian smoothing algorithm is designed for propagating the user-defined sparsely distributed frames into the entire object. The orthotropic frame-field is coupled with the CLFEM model to complete an orthotropic deformable model.
Jianping Cai, Feng Lin, Hock Soon Seah
Chapter 6. Skeletal Animation with Anisotropic Materials
Abstract
In this chapter, we present an integrated real-time system for animation of skeletal characters with anisotropic tissues. Existing geometrically-based skinning techniques suffer from obvious volume distortion artifact, and they cannot produce secondary dynamic motions, such as jiggling effects. Physically-based skinning with FEM models has high computational cost that restricts its practical applications. To solve these problems, we introduce a strain-based Position Based Deformation (PBD) framework for skeletal animation. It bridges the gap between geometric models and physically-based models, and achieves both efficient and physically-plausible performance. Natural secondary motion of soft tissues is produced. Anisotropic deformations are made possible with separately defined stretch and shear properties of the material, using the user-designed frame-field. Owing to the efficiency and stability of our proposed layered constraint solving scheme, we can achieve real-time performance, and the system is robust with large deformations and degenerate cases.
Jianping Cai, Feng Lin, Hock Soon Seah
Chapter 7. Discussions and Conclusions
Abstract
In this chapter, we conclude this monograph with the major techniques developed, and give our perspectives on the future directions of research in this field. This book presents our research on dynamics simulation of deformable models applied in computer graphics field. Both geometrically-based and physically-based approaches have been studied in our work. We focus on deformable objects of anisotropic materials, which are less exploited than those of isotropic materials in existing work. Deformable objects of anisotropic materials are commonly seen in the real world, which exhibit more complicated and flexible mechanical behaviors. Therefore, compared with isotropic models, anisotropic models bring new challenges for designing stable and efficient simulation approaches, and for developing deformation control methods.
Jianping Cai, Feng Lin, Hock Soon Seah
Metadaten
Titel
Graphical Simulation of Deformable Models
verfasst von
Jianping Cai
Feng Lin
Hock Soon Seah
Copyright-Jahr
2016
Electronic ISBN
978-3-319-51031-6
Print ISBN
978-3-319-51030-9
DOI
https://doi.org/10.1007/978-3-319-51031-6