| Various I/O devices have gained popularity in computing technology in the past decades. However, the counter-intuitiveness of these input technologies is obvious in many engineering, gaming and design applications (drawing with a mouse in a CAD application, driving a car in a computer game with a joystick, etc.). With the advent of commodity sketching devices like tablet PC's, digital sketching has become very intuitive and natural for human users and also affordable for the general user.;My research is based on sketch-based computer graphics---using sketches to create and enhance 2D/3D geometric models for a variety of applications in modeling, design and art. This dissertation addresses four research problems, with sketches as the common theme. In sketch-based modeling, I have worked on converting freely drawn 2D sketches of objects into 3D models automatically, or with the minimal use of sketched gestures. An extension of this work constructs navigable 3D models from a single 2D image by treating manual traces of objects in the image as perspective sketches. The third problem that this dissertation discusses is sketch-based inverse lighting, which infers lighting parameters from desired effects roughly sketched by a user on a 3D model. The dissertation culminates in rendering 2D/3D wire-frame sketches that identifies the intricate interplay between sketch-based and non-photorealistic rendering. The goal of this research is to render line drawings efficiently to reduce screen clutter under dynamic conditions while preserving tone and shape. In addition to sketch-based applications, this research also contributes to the area of efficient non-photorealistic rendering under dynamic conditions.;This dissertation identifies the challenges in each problem, then discusses the contributions of my work in detail and identifies the possibilities in each problem beyond the scope of this dissertation. |
