Daniel F. Keefe

We present Dynamic Dragging, a virtual reality (VR) technique for input of smooth 3D trajectories with varying curvature. Users "drag" a virtual pen behind a hand-held tracked stylus to sweep out curving 3D paths in the air. Previous explorations of dragging-style input have established its utility for producing controlled, smooth inputs relative to freehand alternatives. However, a limitation of previous techniques is the reliance on a fixed-length drag line, biasing input toward trajectories of a particular curvature range. Dynamic Dragging explores the design space of techniques utilizing an adaptive drag line that adjusts length dynamically based on the local properties of the input, such as curvature and drawing speed. Finding the right mapping from these local properties to drag line length proves to be critical and challenging. Three potential mappings have been explored, and results of informal evaluations are reported. Initial findings indicate that Dynamic Dragging makes input of many styles of 3D curves easier than traditional drag-style input, allowing drag techniques to approach the flexibility for varied input of more sophisticated and much harder to learn techniques, such as two-handed tape drawing.

We present four studies investigating tools and methodologies for artist-scientist-technologist collaboration in designing multivariate virtual reality (VR) visualizations. Design study 1 identifies the promise of 3D interfaces for rapid VR design and also establishes limitations of the particular tools tested with respect to precision and support for animation. Design study 2 explores animating artist-created visualization designs with scientific 3D fluid flow data. While results captured an accurate sense of flow that was advantageous as compared to the results of study 1, the potential for visual exploration using the design tools tested was limited. Design study 3 reveals the importance of a new 3D interface that overcomes the precision limitation found in study 1 while remaining accessible to artist collaborators. Drawing upon previous results, design study 4 engages collaborative teams in a design process that begins with traditional paper sketching and moves to animated interactive VR prototypes "sketched" by designers in VR using interactive 3D tools. Conclusions from these four studies identify important characteristics of effective artist-accessible VR visualization design tools and lead to a proposed formalized methodology for successful collaborative design that we expect to be useful in guiding future collaborations. We call this proposed methodology scientific sketching.

We present drawing on air, a haptic-aided input technique for drawing controlled 3D curves through space. Drawing on air addresses a control problem with current 3D modeling approaches based on sweeping movement of the hands through the air. Although artists praise the immediacy and intuitiveness of these systems, a lack of control makes it nearly impossible to create 3D forms beyond quick design sketches or gesture drawings. Drawing on air introduces two new strategies for more controlled 3D drawing: one-handed drag drawing and two-handed tape drawing. Both approaches have advantages for drawing certain types of curves. We describe a tangent preserving method for transitioning between the two techniques while drawing. Haptic-aided redrawing and line weight adjustment while drawing are also supported in both approaches. In a quantitative user study evaluation by illustrators, the one and two-handed techniques performed at roughly the same level and both significantly outperformed freehand drawing and freehand drawing augmented with a haptic friction effect. We present the design and results of this experiment, as well as user feedback from artists and 3D models created in a style of line illustration for challenging artistic and scientific subjects.