Master Thesis: Hair Simulation & Rendering Mike Lansink (0088714) Human Media Interaction Department of Computer Science University Twente Graduation Committee: Dr. Job Zwiers October 2009 – June 2010 Dr. Mannes Poel 7522 NB Enschede Ir. Herwin van Welbergen The Netherlands Master Thesis: Hair Simulation & Rendering Mike Lansink Master Thesis: Hair Simulation & Rendering Abstract Chapter: Chapter: 2 Master Thesis: Hair Simulation & Rendering Mike Lansink Table of Contents Table of Contents ................................................................................................................................ 3 List of Figures ....................................................................................................................................... 5 List of Tables ........................................................................................................................................ 6 Abstract ................................................................................................................................................... 7 Preface ..................................................................................................................................................... 8 1. Introduction ..................................................................................................................................... 9 1.1. Project Goal ........................................................................................................................... 10 1.2. Overview of the Thesis .......................................................................................................... 10 2. Natural Hair Properties ................................................................................................................. 11 2.1. Individual Hair Strands .......................................................................................................... 11 2.1.1. Hair Shape ..................................................................................................................... 11 2.1.2. Hair Cross Section .......................................................................................................... 12 2.1.3. Hair Mechanical Properties ........................................................................................... 13 2.1.4. Hair Optical Properties .................................................................................................. 15 2.2. Full Hair Coupe ...................................................................................................................... 17 2.2.1. Hair Distribution ............................................................................................................ 17 2.2.2. Hair Motion ................................................................................................................... 17 2.2.3. Hair Optical Properties .................................................................................................. 18 3. Related Work ................................................................................................................................. 19 3.1. Hair Modelling ....................................................................................................................... 19 3.1.1. Hair Layout & Growth .................................................................................................... 19 3.1.2. Hair Modelling & Styling ................................................................................................ 20 3.2. Hair Animation ...................................................................................................................... 27 3.2.1. Individual Hair Strands .................................................................................................. 27 3.2.2. Full Hair Coupe .............................................................................................................. 30 3.3. Hair Rendering ....................................................................................................................... 32 3.3.1. Hair Representation ...................................................................................................... 32 3.3.2. Hair Illumination ............................................................................................................ 33 4. Hair Simulation & Rendering Framework...................................................................................... 40 4.1. Design .................................................................................................................................... 40 4.1.1. Cosserat Rods ................................................................................................................ 42 4.1.2. Hair Collision .................................................................................................................. 57 Abstract 4.1.3. Energy Minimization ...................................................................................................... 66 Chapter: Chapter: 3 Master Thesis: Hair Simulation & Rendering Mike Lansink 4.1.4. Hair Layout & Growth .................................................................................................... 72 4.1.5. Hair Illumination ............................................................................................................ 82 4.1.6. Hair Shadowing .............................................................................................................. 87 4.2. Results ................................................................................................................................... 91 4.2.1. Input .............................................................................................................................. 91 4.2.2. Work Flow ..................................................................................................................... 96 4.2.3. Output ........................................................................................................................... 98 5. Conclusions .................................................................................................................................... 99 Appendices .......................................................................................................................................... 100 Appendix A ...................................................................................................................................... 100 Hair Shader .................................................................................................................................. 100 Head Shader ................................................................................................................................ 102 Opacity Shader ............................................................................................................................ 103 Appendix B ...................................................................................................................................... 105 Input Files .................................................................................................................................... 105 Appendix C ...................................................................................................................................... 107 Hair Coupe 1 ................................................................................................................................ 107 Hair Coupe 2 ................................................................................................................................ 108 Hair Coupe 3 ................................................................................................................................ 109 Hair Coupe 4 ................................................................................................................................ 110 Appendix D ...................................................................................................................................... 111 Hardware ..................................................................................................................................... 111 Software ...................................................................................................................................... 111 Bibliography ......................................................................................................................................... 112 Index .................................................................................................................................................... 118 Abstract Chapter: Chapter: 4 Master Thesis: Hair Simulation & Rendering Mike Lansink List of Figures Figure 1. Longitudinal Section of Hair ................................................................................................... 12 Figure 2. Cross Section of Hair............................................................................................................... 13 Figure 3. Hair Bending and Twisting ...................................................................................................... 14 Figure 4. Marschner Illumination Model ............................................................................................... 16 Figure 5. Backlighting of Blond Hair .....................................................................................................