Realistic rendering of a multi-layered human body model

Cataloged from PDF version of article.In this thesis study, a framework is proposed and implemented for the realistic rendering of a multi-layered human body model while it is moving. The proposed human body model is composed of three layers: a skeleton layer, a muscle layer, and a skin layer. The skeleton layer, represented by a set of joints and bones, controls the animation of the human body model using inverse kinematics. Muscles are represented by action lines, which are defined by a set of control points. The action line expresses the force produced by a muscle on the bones and on the skin mesh. The skin layer is modeled in a 3D modeler and deformed during animation by binding the skin layer to both the skeleton layer and the muscle layer. The skin is deformed by a two-step algorithm according to the current state of the skeleton and muscle layers. In the first step, the skin is deformed by a variant of the skinning algorithm, which deforms the skin based on the motion of the skeleton. In the second step, the skin is deformed by the underlying muscular layer. Visual results produced by the implementation is also presented. Performance experiments show that it is possible to obtain real-time frame rates for a moderately complex human model containing approximately 33,000 triangles on the skin layerYeşil, Mehmet ŞahinM.S

Animation, Simulation, and Control of Soft Characters using Layered Representations and Simplified Physics-based Methods

Realistic behavior of computer generated characters is key to bringing virtual environments, computer games, and other interactive applications to life. The plausibility of a virtual scene is strongly influenced by the way objects move around and interact with each other. Traditionally, actions are limited to motion capture driven or pre-scripted motion of the characters. Physics enhance the sense of realism: physical simulation is required to make objects act as expected in real life. To make gaming and virtual environments truly immersive,it is crucial to simulate the response of characters to collisions and to produce secondary effects such as skin wrinkling and muscle bulging. Unfortunately, existing techniques cannot generally achieve these effects in real time, do not address the coupled response of a character's skeleton and skin to collisions nor do they support artistic control. In this dissertation, I present interactive algorithms that enable physical simulation of deformable characters with high surface detail and support for intuitive deformation control. I propose a novel unified framework for real-time modeling of soft objects with skeletal deformations and surface deformation due to contact, and their interplay for object surfaces with up to tens of thousands of degrees of freedom.I make use of layered models to reduce computational complexity. I introduce dynamic deformation textures, which map three dimensional deformations in the deformable skin layer to a two dimensional domain for extremely efficient parallel computation of the dynamic elasticity equations and optimized hierarchical collision detection. I also enhance layered models with responsive contact handling, to support the interplay between skeletal motion and surface contact and the resulting two-way coupling effects. Finally, I present dynamic morph targets, which enable intuitive control of dynamic skin deformations at run-time by simply sculpting pose-specific surface shapes. The resulting framework enables real-time and directable simulation of soft articulated characters with frictional contact response, capturing the interplay between skeletal dynamics and complex,non-linear skin deformations

Layered Deformable Models with Implicit Surfaces

Several challenging problems in the animation of deformable objects can be solved by combining existing models with implicit surfaces. The latter are used as an extra layer which coats any kind of structure that moves and deforms over time. Implicit surfaces detect collisions, model local deformations, and transmit response forces to the inner structures. They also control the variations of the object's volume. We present several applications from the animation of organic shapes to the simulation of soft inelastic substances that can separate into smaller pieces or fuse into larger ones. R esum e Plusieurs problemes difficiles dans le domaine de l'animation d'objets deformables peuvent etre resolus en combinant les modeles existants avec des surfaces implicites. Utilisees pour habiller une structure en mouvement, ces dernieres detectent les collisions, modelisent les deformations locales qui en resultent, et transmettent les forces de reponse a la structure interne. Elles peuvent eg..