|dc.description.abstract||Drawing is the earliest form of visual depiction. The goal of this thesis is to facilitate and
accelerate drawing for amateurs as well as for expert designers and illustrators, employing
graphics, image processing and interaction techniques. As this is a broad spectrum to
tackle, we identify three specific problems related to drawing, and propose computer tools
to help users to overcome the main challenges on each domain.
In Chapter 2 we present an interactive drawing tool to help people practice traditional
drawing-by-observation techniques. We build this tool supported by a number of techniques
to help people gain consciousness of the shapes in a scene. We automatically extract visual
guides from a model photograph. The tool's interface displays these information and offer
corrective feedback to guide its manual reproduction.
In Chapter 3 we propose a method to help designers to enrich their drawings with color and
shading. Professionals frequently draw curvature lines to convey bending of smooth surfaces
in concept sketches. We exploit this information and extrapolate curvature lines in a rough
concept sketch. This extrapolation allows us to recover the intended 3D curvature field and
surface normal at each pixel, to create shading and texturing on top of the sketch.
In Chapter 4 we propose a tool that helps users to fabricate wire wrapped jewelry.
Analogous to physical 3D drawing, this form of handmade jewelry can be seen as taking
sketches into the physical world. The presented method assist the user in the main challenges of creating 2D wire-wrapped jewelry from a 2D drawing: decomposing the input into a set of wires, and bending the wires to give them shape. ||en_US