Shape-changing displays enable real-time visualization and haptic exploration of 3D surfaces. However, many shape-changing displays are composed of individually actuated rigid bodies, which makes them both mechanically complex and unable to form smooth surfaces. In this work, we build a multi-stable curved line display inspired by physical splines. By using circular splines to initialize a discrete elastic rods simulator, we can model multiple stable shapes that fit specific boundary conditions. We then generate actuation instructions based on the circular spline initialization to drive the physical display. We demonstrate our display’s ability to create 16 shapes with 8 different boundary conditions. Our display is consistent in shape output, with an average standard deviation in height of 0.75 mm or 0.47% of the display’s maximum vertical range. We also show that our model is consistent with our display, with a mean RMSE of 6.68 mm or 3.85% of the display’s maximum vertical range for shapes we could stably simulate. We then demonstrate potential scalability by simulating a multi-segment version of the system and show the display’s ability to withstand loads during contour following in haptic exploration.

We increasingly rely on up-to-date, data-driven graphs to understand our environments and make informed decisions. However, many of the methods blind and visually impaired users (BVI) rely on to access data-driven information do not convey important shape-characteristics of graphs, are not refreshable, or are prohibitively expensive. To address these limitations, we introduce two refreshable, 1-DOF audio-haptic interfaces based on haptic cues fundamental to object shape perception. Slide-tone uses finger position with sonification, and Tilt-tone uses fingerpad contact inclination with sonification to provide shape feedback to users. Through formative design workshops (n = 3) and controlled evaluations (n = 8), we found that BVI participants appreciated the additional shape information, versatility, and reinforced understanding these interfaces provide; and that task accuracy was comparable to using interactive tactile graphics or sonification alone. Our research offers insight into the benefits, limitations, and considerations for adopting these haptic cues into a data visualization context.