Product designers extensively use sketches to create and communicate 3D shapes and thus form an ideal audience for sketch-based modeling, nonphotorealistic rendering and sketch filtering. However, sketching requires significant expertise and time, making design sketches a scarce resource for the research community. We introduce OpenSketch, a dataset of product design sketches aimed at offering a rich source of information for a variety of computer-aided design tasks. OpenSketch contains more than 400 sketches representing 12 man-made objects drawn by 7 to 15 product designers of varying expertise. We provided participants with front, side and top views of these objects, and instructed them to draw from two novel perspective viewpoints. This drawing task forces designers to construct the shape from their mental vision rather than directly copy what they see. They achieve this task by employing a variety of sketching techniques and methods not observed in prior datasets. Together with industrial design teachers, we distilled a taxonomy of line types and used it to label each stroke of the 214 sketches drawn from one of the two viewpoints. While some of these lines have long been known in computer graphics, others remain to be reproduced algorithmically or exploited for shape inference. In addition, we also asked participants to produce clean presentation drawings from each of their sketches, resulting in aligned pairs of drawings of different styles. Finally, we registered each sketch to its reference 3D model by annotating sparse correspondences. We provide an analysis of our annotated sketches, which reveals systematic drawing strategies over time and shapes, as well as a positive correlation between presence of construction lines and accuracy. Our sketches, in combination with provided annotations, form challenging benchmarks for existing algorithms as well as a great source of inspiration for future developments.We illustrate the versatility of our data by using it to test a 3D reconstruction deep network trained on synthetic drawings, as well as to train a filtering network to convert concept sketches into presentation drawings. We distribute our dataset under the Creative Commons CC0 license: Https://ns.inria.fr/d3/OpenSketch.

Within the field of industrial design, sketches play a significant role for communication. Sketching represents a language for designers to explore options and support creativity, and to express visions and solutions to teams, clients and other stakeholders. Considering the many different goals and formats professional sketches (and visualisations in general) have in practice, this paper suggests to also explicitly distinguish and teach the various factors that should be taken into account for each specific type of sketch: uncover why sketches look the way the look. Several authors have in the past described classifications of design sketches and drawings, mostly assigned to specific design stages. However these scholars do not specifically describe the communication factors, nor do they provide clues or guidelines for implementation. The case study on which the research was based was executed in close collaboration between University and Dutch design agency Vanderveer Designers, it concerned the Thule Yepp Nexxt child bike seat project they ran, which was awarded with the ‘best of the best’ Red Dot Award and the IF Gold award. The case study has helped to conclude that sketches vary along an extensive range of dimensional axes. Further, the visual database of sketches helped to uncover the various characteristics sketches could have. Correlating (1) specific sketches with (2) the factors defining them and (3) the outcome characteristics together will help students and designers, agencies and clients to better understand and interpret each other.