Real-Time Physics Based Simulation for 3D Computer Graphics
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Georgia State University ScholarWorks @ Georgia State University Computer Science Dissertations Department of Computer Science 12-18-2013 Real-time Physics Based Simulation for 3D Computer Graphics Xiao Chen Georgia State University Follow this and additional works at: https://scholarworks.gsu.edu/cs_diss Recommended Citation Chen, Xiao, "Real-time Physics Based Simulation for 3D Computer Graphics." Thesis, Georgia State University, 2013. https://scholarworks.gsu.edu/cs_diss/79 This Thesis is brought to you for free and open access by the Department of Computer Science at ScholarWorks @ Georgia State University. It has been accepted for inclusion in Computer Science Dissertations by an authorized administrator of ScholarWorks @ Georgia State University. For more information, please contact [email protected]. REAL-TIME PHYSICS BASED SIMULATION FOR 3D COMPUTER GRAPHICS AT GEORGIA STATE UNIVERSITY by XIAO CHEN Under the Direction of Ying Zhu ABSTRACT Restoration of realistic animation is a critical part in the area of computer graphics. The goal of this sort of simulation is to imitate the behavior of the transformation in real life to the greatest extent. Physics-based simulation provides a solid background and proficient theories that can be applied in the simulation. In this dissertation, I will present real-time simulations which are physics-based in the area of terrain deformation and ship oscillations. When ground vehicles navigate on soft terrains such as sand, snow and mud, they often leave distinctive tracks. The realistic simulation of such vehicle-terrain interaction is important for ground based visual simulations and many video games. However, the existing research in terrain deformation has not addressed this issue effectively. In this dissertation, I present a new terrain deformation algorithm for simulating vehicle-terrain interaction in real time. The algorithm is based on the classic terramechanics theories, and calculates terrain deformation according to the vehicle load, velocity, tire size, and soil concentration. As a result, this algorithm can simulate different vehicle tracks on different types of terrains with different vehicle properties. I demonstrate my algorithm by vehicle tracks on soft terrain. In the field of ship oscillation simulation, I propose a new method for simulating ship motions in waves. Although there have been plenty of previous work on physics based fluid- solid simulation, most of these methods are not suitable for real-time applications. In particular, few methods are designed specifically for simulating ship motion in waves. My method is based on physics theories of ship motion, but with necessary simplifications to ensure real-time performance. My results show that this method is well suited to simulate sophisticated ship motions in real time applications. INDEX WORDS: Terrain deformation, Ship oscillation, Virtual reality REAL-TIME PHYSICS BASED SIMULATION FOR 3D COMPUTER GRAPHICS AT GEORGIA STATE UNIVERSITY by XIAO CHEN A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy In the College of Arts and Sciences Georgia State University 2013 Copyright by Xiao Chen 2013 REAL-TIME PHYSICS BASED SIMULATION FOR 3D COMPUTER GRAPHICS AT GEORGIA STATE UNIVERSITY by XIAO CHEN Committee Chair: Dr. Ying Zhu Committee: Dr. G. Scott Owen Dr. Rajshekhar Sunderraman Dr. Dajun Dai (Geosciences) Electronic Version Approved: Office of Graduate Studies College of Arts and Sciences Georgia State University December 2013 iv DEDICATION I would like to dedicate this Doctoral dissertation to my father, Jianrong Chen, my mother, Xiaoling Song, my grandfather, Mingxin Song, my grandmother, Jifen Zeng and my uncle Jianping Song. There is no doubt in my mind that without their continued support and counsel I could not have completed this process. v ACKNOWLEDGEMENTS At first, I would like to express my sincere gratitude to my advisor Dr. Ying Zhu for his continuous support during my Ph.D research. Besides my advisor, I would like to thank all of my thesis committee members: Dr. G. Scott Owen, Dr. Rajshekhar Sunderraman, and Dr. Dajun Dai for their encouragement and advices. The text of this dissertation includes reprints of the following previously published papers: Chen, X., Zhu, Y., Shader based polygon stitching and its application in deformable terrain simulation, Image and Graphics (ICIG), 2011 Sixth International Conference on, pp 885-890 Zhu, Y., Chen, X. and Owen G.S., Terramechanics based terrain deformation for real-time off- road vehicle simulation, Advances in Visual Computing Lecture Notes in Computer Science Volume 6938, 2011, pp 431-440 Chen, X., Wang, G. and Zhu, Y., Evaluating a Mobile Pedestrian Safety Application in a Virtual Urban Environment, VRCAI '12 Proceedings of the 11th ACM SIGGRAPH International Conference on Virtual-Reality Continuum and its Applications in Industry, pp 175-180 Chen, X., Wang, G. and Zhu, Y., Real-time Simulation of Ship Motions in Waves, Advances in Visual Computing Lecture Notes in Computer Science Volume 7431, 2012, pp 71-80 Chen, X., Zhu, Y., Real-time Simulation of Vehicle Tracks on Soft Terrain, International Symposium on Visual Computing 2013, Part I, LNCS 8033 proceedings vi TABLE OF CONTENTS ACKNOWLEDGEMENTS ......................................................................................................... v TABLE OF CONTENTS ............................................................................................................ vi LIST OF FIGURES ...................................................................................................................... x 1. INTRODUCTION..................................................................................................................... 1 1.1 Problem Statement.................................................................................................. 1 1.2 My Contributions .................................................................................................... 2 1.3 Organization of This Dissertation ......................................................................... 3 2. PHYSICS IN GAMES AND SIMULATIONS ....................................................................... 3 2.1 Deformable Object .................................................................................................. 5 2.1.1 Terrain Deformation ..................................................................................................... 5 2.1.2 Object Destruction......................................................................................................... 6 2.2 Rigid Body ............................................................................................................... 7 2.3 Motion ...................................................................................................................... 8 2.2.1 Ship Oscillation ............................................................................................................. 8 2.2.2 Little Big Planet ............................................................................................................ 9 2.3 Collision Detection .................................................................................................. 9 2.3.1 Application of Collision Detection ............................................................................. 11 2.4 Particle System ...................................................................................................... 11 2.4.1 Fire .............................................................................................................................. 12 2.4.2 Smoke .......................................................................................................................... 13 vii 2.4.3 Rain.............................................................................................................................. 13 3. TERRAIN DEFORMATION ................................................................................................ 15 3.1 Introduction ........................................................................................................... 15 3.2 Previous Work of Terrain Deformation ............................................................. 16 3.2.1 Terrain Compression .................................................................................................. 16 3.2.2 Tire Tread Pattern ....................................................................................................... 20 3.2.3 Debris ........................................................................................................................... 21 3.3 Terrain-mechanics ................................................................................................ 21 3.3.1 Theories on Vehicle-Terrain Interaction ................................................................... 23 3.3.2 A Terramechanics Model for Terrain Compression ................................................. 29 3.3.3 Calculating Terrain Deformation .............................................................................. 30 3.3.4 Lateral Displacement .................................................................................................. 32 3.3.5 Generation of Dust Particles ...................................................................................... 34 3.3.6 Other Problems ..........................................................................................................