This page lists my academic accomplishments, specifically peer-reviewed conference papers and journals. I list my publications by date, including publications I contributed to during undergraduate research. Between 2011 and 2013, I worked in industry (gasp!) and did not publish, hence the gap in academic work. Please see my Google Scholar page for the most updated list of publications and my CV for more complete career document.

HapticPrint: Designing Feel Aesthetics for 3D Printing
Cesar Torres, Tim Campbell, Neil Kumar, and Eric Paulos

Digital fabrication has enabled massive creativity in hobbyist communities and professional product design. These emerg- ing technologies excel at realizing an arbitrary shape or form; however these objects are often rigid and lack the feel desired by designers. We aim to enable physical haptic design in passive 3D printed objects. This paper identifies two core areas for extending physical design into digital fabrication: designing the external and internal haptic characteristics of an ob- ject. We present HapticPrint as a pair of design tools to easily modify the feel of a 3D model. Our external tool maps tex- tures and UI elements onto arbitrary shapes, and our internal tool modifies the internal geometry of models for novel com- pliance and weight characteristics. We demonstrate the value of HapticPrint with a range of applications that expand the aesthetics of feel, usability, and interactivity in 3D artifacts.

To appear at UIST 2015.
Towards Digital Apprenticeship: Wearable Activity Recognition in the Workshop Setting
Tim Campbell, Jonathan Harper, Björn Hartmann and Eric Paulos

Online communities for sharing instructional content have grown from a renewed interest in DIY culture. However, it is difficult to convey the tacit knowledge implicit in certain skills. We identify the need for Digital Apprenticeship, where workshop activities are sensed and analyzed for both quantitative and qualitative measures. We evaluated this concept with an activity recognition system for carpentry tools. Using a single ring-worn inertial measurement unit (IMU), we collected data from 15 participants using 5 hand and power tools. Our window-based multi-class SVM achieves 82% accuracy with realistic training scenario and outputs user-friendly event activity. We investigate how these results contextualize to applications in digital apprenticeship, namely tutorial authoring, content following and technique feedback.

Fl.UIs: Liquid-Mediated Vision-Based Touch Surfaces
Tim Campbell, Cesar Torres, Eric Paulos

Fluid User Interfaces, Fl.UIs, are touch interactions formed with passive, unpowered hardware and an overhead computer vision system. The easy-to-build touch surfaces move colored liquid in response to a user's touch, which is easily detected with a camera.