Non-contact Breathing Analysis 3D Scanning and Printing Deformation Object Control Deformable Object Collision Visual Bioinformatics
Animation Computer Graphics Advanced Computer Graphics Game Design Shader and GPU Programming
Deformation Control in Physically-driven Simulation

Deformable Object Behavior Reconstruction Derived through Simultaneous Geometric and Material Property Estimation
S. Transue and M. Choi

Abstract: We present a methodology of accurately reconstructing the deformation and surface characteristics of a scanned 3D model recorded in real-time within a Finite Element Model (FEM) simulation. Based on a sequence of generated surface deformations defining a reference animation, we illustrate the ability to accurately replicate the deformation behavior of an object composed of an unknown homogeneous elastic material. We then formulate the procedural generation of the internal geometric structure and material parameterization required to achieve the recorded deformation behavior as a non-linear optimization problem. In this formulation the geometric distribution (quality) and density of tetrahedral components are simultaneously optimized with the elastic material parameters (Young's Modulus and Possion's ratio) of a procedurally generated FEM model to provide the optimal deformation behavior with respect to the recorded surface.

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Interactive Control of Deformable-object Animations through Control Metaphor Pattern Adherence
S. Transue and M. Choi

Abstract: In this paper we present an adaptive and intuitive methodology for controlling the localized deformations of physically simulated objects using an intuitive pattern-based control interface. To maximize the interactive component presented in this approach we consolidate existing feedback mechanisms in deformable-body control techniques to provide intuitive editing metaphors for stretching, bending, twisting, and compressing simulated objects. The resulting movements created by these control metaphors are validated using imposed behavior evaluation and the effectiveness of this approach is demonstrated through interactively generated compound movements that introduce complex local deformations of objects in existing physical animations.

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Enhanced Second-Order Implicit Constraint Enforcement for Dynamic Simulation" KSII Transaction on Internet and Information Systems
M. Hong, S. Welch, S. Jung, M. Choi, D. Park

Abstract: This paper proposes a second-order implicit constraint enforcement method which yields enhanced controllability compared to a first-order implicit constraints enforcement method. Although the proposed method requires solving a linear system twice, it yields superior accuracy from the constraints error perspective and guarantees the precise and natural movement of objects, in contrast to the first-order method. Thus, the proposed method is the most suitable for exact prediction simulations. This paper describes the numerical formulation of second-order implicit constraints enforcement. To prove its superiority, the proposed method is compared with the firstorder method using a simple two-link simulation. In this paper, there is a reasonable discussion about the comparison of constraints error and the analysis of dynamic behavior using kinetic energy and potential energy.

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Interactive Motion Control of Deformable Objects Using Localized Optimal Control
Hongjun Jeon and Min-Hyung Choi

Abstract: In this paper we present a novel interactive method and interface techniques for controlling the behavior of physically-based simulation of deformable objects. The goal of our research is to provide users an ability to control the motion which appears physically correct, preserves the moving pattern of the original motion, and satisfies goals for a deformable object. In our approach, a user can select any part of the deformable structure, called control points, and can define target poses by moving control points. A user also can define target poses then our system automatically generates the motion path to achieve the target pose. With this technique patient specific organ simulation can be achieved by using a stream of image data. A series of sectional images can be the target poses. The optimal path generator computes the required control parameters that steer the intended node to the desired goal position while preserving the moving pattern of the original motion. It guarantees that the edited motion is physically conforming and natural.

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Physics-Based Deformable Object Simulation in Ubiquitous Computing Environments
Sunhwa Jung, Hongjun Jeon, and Min-Hyung Choi

Abstract: Ubiquity is a trend and vision of modern computer science. Planting physics-based deformable object simulation, which provides realism to animation and medical simulation, into ubiquitous computing environments will make a step forward to envisioned realism in the ubiquity of computation. The essential components of embedding physics-based deformable simulation to ubiquitous computational environments are adaptive simulation paradigm and data driven simulation techniques. In this paper we examine the feasibility of physics-based deformable object simulation in ubiquitous computing environments and present the possible applications of ubiquitous deformable object simulation.

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Controllable Simulation of Deformable Objects using the Heuristic Optimal Control Method
Hongjun Jeon and Min-Hyung Choi

Abstract: Physically-based simulation techniques have been widely used in computer graphics because it creates highly realistic animation. However, due to the limitation of passive simulation and simplified modeling methods, it is very difficult to control the behavior of deformable objects directly. Ability to control the behavior of deformable objects is a very important feature for an effective simulation. In this paper, we present a novel interactive method and interface techniques for controlling the behavior of physically-based simulation of deformable objects. In our approach, an animator can select any part of the deformable structure and drag it to the desired location then our system automatically generates the motion path using the heuristic optimal method. Animators can focus on the final pose of the controlled object, without worrying about how to achieve the goal pose. Based on the displacement distance and the previous trajectory of the intended node, the optimal path generator computes the required control parameters that steer the intended node to the desired goal position while preserving the style of the original motion and minimizing the energy to achieve the goal pose. The goal oriented control scheme enables users to interactively control and redirect the motion of deformable objects and guarantees that the edited motion is physically conforming.

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Implicit Constraint Enforcement for Rigid Body Dynamic Simulation
Min Hong, Samuel Welch, John Trapp, and Min-Hyung Choi

Abstract:
The paper presents a simple, robust, and effective constraint enforcement scheme for rigid body dynamic simulation. The constraint enforcement scheme treats the constraint equations implicitly providing stability as well as accuracy in constrained dynamic problems. The method does not require ad-hoc problem dependent parameters. We describe the formulation of implicit constraint enforcement for both holonomic and non-holonomic cases in rigid body simulation. A first order version of the method is compared to a first order version of the well-known Baumgarte stabilization.

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