Pen Meets Desk: Above-surface Drawing with Encountered-type Haptics Using an Extendable Pen

Hand drawing in immersive virtual environments works best on a virtual surface aligned with a counterpart physical surface. However, physical surfaces are rarely portable and therefore hard-to-align with the virtual surfaces in the air. To overcome this limitation, we propose a mechanical pen device that changes the length to render encountered haptic feedback. We evaluated our proof-of-concept device in a user study and published the 3D printable data for reproducibility. We designed a trajectory tracing task on 0-/15-/30-degree slanted canvases and compared drawing with and without our encountered haptic rendering in terms of tracing accuracy, usability, and workload. The results revealed that our method has the potential to afford better line tracing performance and reduce workload. We discuss how precise device length controls can contribute to improving usability and decreasing workload on a steep canvas.