Efficient Sketch-Based 3D Character Modelling
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Efficient Sketch-Based 3D Character Modelling ISMAIL KHALID KAZMI A thesis submitted in partial fulfilment of the requirements of Bournemouth University for the degree of Doctor of Philosophy National Centre for Computer Animation Bournemouth University June, 2016 Copyright This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with its author and due acknowledgement must always be made of the use of any material contained in, or derived from, this thesis. ii Abstract Sketch-based modelling (SBM) has undergone substantial research over the past two decades. In the early days, researchers aimed at developing techniques useful for modelling of architectural and mechanical models through sketching. With the advancement of technology used in designing visual effects for film, TV and games, the demand for highly realistic 3D character models has skyrocketed. To allow artists to create 3D character models quickly, researchers have proposed several techniques for efficient character modelling from sketched feature curves. Moreover several research groups have developed 3D shape databases to retrieve 3D models from sketched inputs. Unfortunately, the current state of the art in sketch-based organic modelling (3D character modelling) contains a lot of gaps and limitations. To bridge the gaps and improve the current sketch-based modelling techniques, this research aims to develop an approach allowing direct and interactive modelling of 3D characters from sketched feature curves, and also make use of 3D shape databases to guide the artist to create his / her desired models. The research involved finding a fusion between 3D shape retrieval, shape manipulation, and shape reconstruction / generation techniques backed by an extensive literature review, experimentation and results. The outcome of this research involved devising a novel and improved technique for sketch-based modelling, the creation of a software interface that allows the artist to quickly and easily create realistic 3D character models with comparatively less effort and learning. The proposed research work provides the tools to draw 3D shape primitives and manipulate them using simple gestures which leads to a better modelling experience than the existing state of the art SBM systems. iii Table of Contents Copyright ............................................................................................................................ ii Abstract .............................................................................................................................. iii List of Figures ................................................................................................................... vii List of Tables ..................................................................................................................... xi Acknowledgement ............................................................................................................ xii Declaration ....................................................................................................................... xiv Thesis Outline ................................................................................................................... xv 1 Introduction .............................................................................................................. 17 1.1 Overview ........................................................................................................... 17 1.2 Conventional approaches for character modelling ............................................ 18 1.2.1 Box modelling ........................................................................................... 18 1.2.2 Organic sculpting ...................................................................................... 19 1.2.3 NURBS/Spline Modelling ........................................................................ 20 1.2.4 Photogrammetry ........................................................................................ 20 1.2.5 3D laser scanning ...................................................................................... 21 1.3 Aims and objectives of this research ................................................................. 22 1.4 Contributions ..................................................................................................... 24 1.5 Publications ....................................................................................................... 25 2 Related Work ........................................................................................................... 27 2.1 A Survey of 2D and 3D Shape Descriptors ...................................................... 27 2.1.1 Definition and characteristics of shape descriptors ................................... 28 2.1.2 2D Shape Descriptors................................................................................ 29 2.1.3 3D Shape Descriptors................................................................................ 37 2.1.4 SHREC - 3D Shape Retrieval Contest ...................................................... 46 2.1.5 Comparison & Discussion ........................................................................ 47 2.1.6 Conclusion & Future Research Directions ................................................ 47 2.2 A Survey of Sketch-based Modelling Systems ................................................. 49 iv 2.2.1 SBM Pipeline ............................................................................................ 52 2.2.2 Single View Systems ................................................................................ 53 2.2.3 Multi-view systems ................................................................................... 61 2.2.4 Curve Networks Based Systems ............................................................... 62 2.2.5 Data Driven Systems ................................................................................. 66 2.2.6 Morphing based systems ........................................................................... 68 2.2.7 Conclusion ................................................................................................ 71 3 Efficient Sketch-Based Creation of Detailed Character Models through Data-Driven Mesh Deformations ........................................................................................................... 72 3.1 Introduction ....................................................................................................... 72 3.2 Related Work .................................................................................................... 74 3.3 System Overview .............................................................................................. 77 3.3.1 Sketch Input / Creation ............................................................................. 79 3.3.2 Template Model Retrieval ........................................................................ 81 3.3.3 Occluding contours extraction .................................................................. 87 3.3.4 Correspondence Computation ................................................................... 89 3.3.5 Mesh Deformation .................................................................................... 94 3.4 Results and Comparison.................................................................................. 101 3.5 Conclusion and future work ............................................................................ 105 4 A Hybrid Approach for Character Modelling Using Geometric Primitives and a Shape-from-Shading Algorithm ...................................................................................... 108 4.1 Introduction ..................................................................................................... 108 4.2 Related Work .................................................................................................. 111 4.3 System Overview ............................................................................................ 114 4.3.1 Base Mesh Modeller ............................................................................... 114 4.3.2 Surface Detail Modeller .......................................................................... 120 4.4 Implementation ............................................................................................... 127 4.5 Results and Discussion ................................................................................... 131 v 4.6 Conclusion ...................................................................................................... 133 4.7 Limitations ...................................................................................................... 134 5 Sketch-to-Box: A New Character Modelling Technique ....................................... 135 5.1 Introduction ..................................................................................................... 135 5.2 Related Work .................................................................................................. 142 5.3 System Overview ............................................................................................ 146 5.3.1 Box Modeller .......................................................................................... 148 5.3.2 Muscle Sculptor ...................................................................................... 159