Anatomy in 3dmodeling and digital sculpting

Anatomy in 3dmodeling and digital sculpting

Abstract

Most human figure models use a simplified articulated skeleton consisting of relatively few jointed segments. Magnenat-Thalmann and Thalmann challenged researchers to develop more accurate articulated models for the skeletal support of human figures. They observe that complex motion control algorithms which have been developed for primitive articulated models better suit robotlike characters than they do human figures. In this research paper we discuss about importance of Anatomy in 3dmodeling and digital sculpting.

Anatomy in 3dmodeling and digital sculpting

Introduction

Human figure modeling and animation has been one of the primary areas of research in computer graphics since the early 1970's. The complexity of simulating the human body and its behavior is directly proportional to the complexity of the human body itself, and is compounded by the vast number of movements it is capable of. Although articulated structures containing rigid segments is a reasonable approximation of the human skeleton, most researchers use articulated structures that are too simple to be deemed anatomically appropriate (Gupta 1995). The shoulder, spine, forearm, and hand are typical examples where accuracy is sacrificed for simplicity.

Anatomy-based skeletal models

To address this issue, researchers have revisited the skeletal layer of human figure models to solve some specific problems. In Jack, the shoulder is modeled accurately as a clavicle and shoulder pair. The spatial relationship between the clavicle and shoulder is adjusted based on the position and orientation of the upper arm. In another treatment of the shoulder-arm complex, the Thalmanns use a moving joint based on lengthening the clavicle which produces good results. Monheit and Badler developed a kinematic model of the human spine that improves on the realism with which the torso can be bent or twisted. Scheepers et al. developed a skeleton model which supports anatomically accurate pronation and supination of the two forearm bones. Gourret et al. use realistic bones in their hand skeleton to assist in producing appropriate deformations of the fingers in a grasping task. Ignoring the effects that gravity and other external forces may have on tissue, some researchers have concentrated on the deformations that occur in the vicinity of joints. One simplifying assumption considers the human body as consisting of rigid body parts connected with flexible surfaces at joints. Chadwick et al. use free-form deformations (FFDs) to deform skin surfaces that surround the underlying skeleton. By using abstract muscle operators, a relationship between skeletal parameters (such as joint angles) and the control points of the FFDs is established. For example, tendon muscle operators are used to control deformations near joints (Guo 2004). The Thalmanns use joint-dependent local deformation operators to control the changes that surfaces undergo near flexing joints. Singh models the skin surfaces near joints with polyhedral objects embedded in implicit functions. As the joints move, the implicit functions deform the polyhedral definition, and therefore the skin surface in the vicinity of the joint. Surfaces may also be deformed in areas other than near ...