Real-Time Character Animation for Computer Games

The importance of real-time character animation in computer games has increased considerably over the past decade. Due to advances in computer hardware and the achievement of great increases in computational speed, the demand for more realism in computer games is continuously growing. This paper will present and discuss various methods of 3D character animation and prospects of their real-time application, ranging from the animation of simple articulated objects to real-time deformable object meshes

Jack: A Toolkit for Manipulating Articulated Figures

The problem of positioning and manipulating three dimensional articulated figures is often handled by ad hoc techniques which are cumbersome to use. In this paper, we describe a system which provides a consistent and flexible user interface to a complex representation for articulated figures in a 3D environment. Jack is a toolkit of routines for displaying and manipulating complex geometric figures, and it provides a method of interactively manipulating arbitrary homogeneous transformations with a mouse. These transformations may specify the position and orientation of figures within a scene or the joint transformations within the figures themselves. Jack combines this method of 3D input with a flexible and informative screen management facility to provide a user-friendly interface for manipulating three dimensional objects

Dynamic analysis of anthropomorphic manipulators in computer animation

The thesis examines the motion control and motion coordination of articulated bodies, in particular human models, through the use of dynamic analysis. The work concentrates particularly on the use of dynamic analysis as a tool for creating an animated walking sequence. The aim is to relieve the animator of the tedious specification of unknown parameters of motion control, and instead, to investigate the possibility of shifting this specification and much of the work to the animation software. Using this idea. a higher level of control could be used to coordinate the movement. This has been examined through the use of a Hybrid Inverse and Direct Dynamics System, HIDDS, based on Featherstone's formulation. The inverse system is used to get an initial estimate of the values of the forces and torques needed to move the model to the required position. Once the values of these forces/torques are determined. a direct dynamics system is called to compute the accelerations produced from the influence of the input forces/torques. Double integration over time then gives the new positions. Applications of the hybrid technique can create animation sequences through the use of the graphics editor AnthroPI (Anthropomorphic Programming Interface) especially created for the implementation of the desired results. The problem of ground reaction forces has also been studied and formulated. An algorithm proposed by Kearney for a one-legged hopping machine was extended to the two-legged anthropomorphic model by the introduction of the virtual-leg concept. The dynamics approach showed promise in creating motion sequences which are both natural and realistic and HIDDS proved to be a useful experimental tool on which further research can be based. At its early stage. it provides a middle-level of control. which we believe has the potential to be upgraded to a higher level

Visualization tools for moving objects

In this work we describe the design and implementation of a general framework for visualizing and editing motion planning environments, problem instances, and their solutions. The motion planning problem consists of finding a valid path between a start and a goal configuration for a movable object. The workspace is, in traditional robotics and animation applications, composed of one or more objects (called obstacles) that cannot overlap with the robot. As even the simplest motion planning problems have been shown to be in- tractable, most practical approaches to motion planning use randomization and/or compute approximate solutions. While the tool we present allows the manipulation and evaluation of planner solutions and the animation of any path found by any plan- ner, it is specialized for a class of randomized planners called probabilistic roadmap methods (PRMs). PRMs are roadmap-based methods that generate a graph or roadmap where the nodes represent collision-free configurations and the edges represent feasible paths between those configurations. PRMs typically consist of two phases: roadmap con- struction, where a roadmap is built, and query, where the start and goal configura- tions are connected to the roadmap and then a path is extracted using graph search techniques

Towards adaptive and directable control of simulated creatures

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references (p. 71-77).Interactive animation is used ubiquitously for entertainment and for the communication of ideas. Active creatures, such as humans, robots, and animals, are often at the heart of such animation and are required to interact in compelling and lifelike ways with their virtual environment. Physical simulation handles such interaction correctly, with a principled approach that adapts easily to different circumstances, changing environments, and unexpected disturbances. However, developing robust control strategies that result in natural motion of active creatures within physical simulation has proved to be a difficult problem. To address this issue, a new and versatile algorithm for the low-level control of animated characters has been developed and tested. It simplifies the process of creating control strategies by automatically accounting for many parameters of the simulation, including the physical properties of the creature and the contact forces between the creature and the virtual environment. This thesis describes two versions of the algorithm (one fast and one feature-rich) and the experiments conducted to evaluate its performance.(cont.) The results include interactive animations of active creatures manipulating objects and balancing in response to significant disturbances from their virtual environment. The algorithm is shown to be directable, adaptive, and fast and to hold promise for a new generation of interactive simulations that feature lifelike creatures acting with the same fluidity and grace exhibited by natural beings.by Yeuhi Abe.S.M

Human motion control using inverse kinematics

Cataloged from PDF version of article.Articulated figure animation receives particular attention of the computer graphics society. The techniques for animation of articulated figures range from simple interpolation between keyframes methods to motion-capture techniques. One of these techniques, inverse kinematics, which is adopted from robotics, provides the animator the ability to specify a large quantity of motion parameters that results with realistic animations. This study presents an interactive hierarchical motion control system used for the animation of human figure locomotion. We aimed to develop an articulated figure animation system that creates movements , like goal-directed motion and walking by using motion control techniques at different levels. Inverse Kinematics using Analytical Methods (IKAN) software, which was developed at the University of Pennsylvania, is utilized for controlling the motion of the articulated body using inverse kinematics.Memişoğlu, AydemirM.S

HIGH QUALITY HUMAN 3D BODY MODELING, TRACKING AND APPLICATION

Geometric reconstruction of dynamic objects is a fundamental task of computer vision and graphics, and modeling human body of high fidelity is considered to be a core of this problem. Traditional human shape and motion capture techniques require an array of surrounding cameras or subjects wear reflective markers, resulting in a limitation of working space and portability. In this dissertation, a complete process is designed from geometric modeling detailed 3D human full body and capturing shape dynamics over time using a flexible setup to guiding clothes/person re-targeting with such data-driven models. As the mechanical movement of human body can be considered as an articulate motion, which is easy to guide the skin animation but has difficulties in the reverse process to find parameters from images without manual intervention, we present a novel parametric model, GMM-BlendSCAPE, jointly taking both linear skinning model and the prior art of BlendSCAPE (Blend Shape Completion and Animation for PEople) into consideration and develop a Gaussian Mixture Model (GMM) to infer both body shape and pose from incomplete observations. We show the increased accuracy of joints and skin surface estimation using our model compared to the skeleton based motion tracking. To model the detailed body, we start with capturing high-quality partial 3D scans by using a single-view commercial depth camera. Based on GMM-BlendSCAPE, we can then reconstruct multiple complete static models of large pose difference via our novel non-rigid registration algorithm. With vertex correspondences established, these models can be further converted into a personalized drivable template and used for robust pose tracking in a similar GMM framework. Moreover, we design a general purpose real-time non-rigid deformation algorithm to accelerate this registration. Last but not least, we demonstrate a novel virtual clothes try-on application based on our personalized model utilizing both image and depth cues to synthesize and re-target clothes for single-view videos of different people

Modelling and Animation using Partial Differential Equations. Geometric modelling and computer animation of virtual characters using elliptic partial differential equations.

This work addresses various applications pertaining to the design, modelling and animation of parametric surfaces using elliptic Partial Differential Equations (PDE) which are produced via the PDE method. Compared with traditional surface generation techniques, the PDE method is an effective technique that can represent complex three-dimensional (3D) geometries in terms of a relatively small set of parameters. A PDE-based surface can be produced from a set of pre-configured curves that are used as the boundary conditions to solve a number of PDE. An important advantage of using this method is that most of the information required to define a surface is contained at its boundary. Thus, complex surfaces can be computed using only a small set of design parameters. In order to exploit the advantages of this methodology various applications were developed that vary from the interactive design of aircraft configurations to the animation of facial expressions in a computer-human interaction system that utilizes an artificial intelligence (AI) bot for real time conversation. Additional applications of generating cyclic motions for PDE based human character integrated in a Computer-Aided Design (CAD) package as well as developing techniques to describe a given mesh geometry by a set of boundary conditions, required to evaluate the PDE method, are presented. Each methodology presents a novel approach for interacting with parametric surfaces obtained by the PDE method. This is due to the several advantages this surface generation technique has to offer. Additionally, each application developed in this thesis focuses on a specific target that delivers efficiently various operations in the design, modelling and animation of such surfaces.The project files will not be available online