How2Sketch: Generating Easy-To-Follow Tutorials for Sketching 3D Objects

TL;DR

How2Sketch automatically generates step-by-step drawing tutorials for 3D objects, simplifying the creation process and aiding novices in sketching with correct perspective and proportions.

Contribution

It introduces a novel algorithm that automatically creates easy-to-follow tutorials for arbitrary 3D models, reducing the need for expert knowledge and manual effort.

Findings

Tutorials are effective for a variety of man-made objects.

Users can follow generated tutorials to accurately sketch 3D objects.

The method simplifies the construction of drawing scaffolds with geometric primitives.

Abstract

Accurately drawing 3D objects is difficult for untrained individuals, as it requires an understanding of perspective and its effects on geometry and proportions. Step-by-step tutorials break the complex task of sketching an entire object down into easy-to-follow steps that even a novice can follow. However, creating such tutorials requires expert knowledge and is a time-consuming task. As a result, the availability of tutorials for a given object or viewpoint is limited. How2Sketch addresses this problem by automatically generating easy-to-follow tutorials for arbitrary 3D objects. Given a segmented 3D model and a camera viewpoint,it computes a sequence of steps for constructing a drawing scaffold comprised of geometric primitives, which helps the user draw the final contours in correct perspective and proportion. To make the drawing scaffold easy to construct, the algorithm solves for an ordering among the scaffolding primitives and explicitly makes small geometric modifications to the size and location of the object parts to simplify relative positioning. Technically, we formulate this scaffold construction as a single selection problem that simultaneously solves for the ordering and geometric changes of the primitives. We demonstrate our algorithm for generating tutorials on a variety of man-made objects and evaluate how easily the tutorials can be followed with a user study.