href="#ulink_9db5effa-0411-5f21-ba73-93f86b5da20c">Section 3.3.3. These approaches can productively be combined. In the following, we start with some general perspectives and techniques useful for haptic design, then delve into several specific schemas that haptic designers have made use of: sources of inspiration and conceptual scaffolding of what the finished design may be.
General Methodological Perspectives
Some higher-level perspectives offer useful outcome targets, collections of methods, and design attitudes to guide haptic practitioners in their process. DIY (do-it-yourself) haptics categorize feedback styles and design principles [Hayward and MacLean 2007, MacLean and Hayward 2008]. Ambience is proposed as one target for a haptic experience, where information moves calmly from a person’s periphery to their focused attention [MacLean 2009]. Haptic illusions can serve as concise ways to explore the sense of touch, explain concepts to novices and inspire interfaces [Hayward 2008]. “Simple Haptics” [Simple Haptics 2016], epitomized by haptic sketching, emphasizes rapid, hands-on exploration of a creative space [Moussette 2010, Moussette and Banks 2011] and has been enabled by recent and radical advances in mechatronic rapid prototyping technology. The notion of distributed cognition [Hutchins 1995] has particular relevance for haptic design, suggesting that people situate their thinking both in their bodies and in the environment. Finally, haptics courses are extremely helpful collections of skills and techniques, with foci including perception, control, and design [Okamura et al. 2012, Jones 2014]. Each of these different perspectives can help haptic designers think about how to design haptics more generally, and can augment schemas inspired from other fields.
Design Schemas Inspired by Audio, Video and Multimedia
Haptic designers have often appropriated design elements used in other fields. Haptic Icons [Maclean and Enriquez 2003], tactons [Brewster and Brown 2004], and haptic phonemes [Enriquez et al. 2006] are small, compositional, iconic representations of haptic ideas, inspired by comparable elements from graphical and sound design [Gaver 1986]. Touch TV [Modhrain and Oakley 2001], tactile movies [Kim et al. 2009], haptic broadcasting [Cha et al. 2009], and Feel Effects [Israr et al. 2014] aim to add haptics to existing media types, especially video.
Music analogies and metaphors have frequently inspired haptic design tools, especially VT sensations. The Vibrotactile Score, a graphical editing tool representing vibration patterns as musical notes, is a major example [Lee and Choi 2012, Lee et al. 2009]. Other musical metaphors include the use of rhythm, often represented by musical notes and rests [Ternes and MacLean 2008, Brown et al. 2005, Chan et al. 2008, Brown et al. 2006b]. Earcons and tactons are represented with musical notes [Brewster et al. 1993, Brewster and Brown 2004], complete with tactile analoges of crescendos and sforzandos [Brown et al. 2006a]. The concept of a VT concert found relevant tactile analogues to musical pitch, rhythm, and timbre for artistic purposes [Gunther et al. 2002]. In the reverse direction, tactile dimensions have also been used to describe musical ideas [Eitan and Rothschild 2010].
Language of Touch
The language of tactile perception, especially its affective (emotional) terms, is an obvious possibility for framing haptic design. Language is a promising way to capture user experience, both more generally and for haptics in particular [Obrist et al. 2013], and can reveal useful parameters, e.g., how pressure influences affect [Zheng and Morrell 2012]. In Section 3.1.4, we noted how individuals differ in their experience of haptic stimuli, and this certainly has implications for the generation of stable, broadly understandable design languages in this modality. Reiterating those points: relatively (although not perfectly) consistent sensory dimensions have been established with psychophysical studies for both synthetic haptics and real-world materials, but for meaning-mapping, agreement becomes highly variable. Touch clearly communicates strongly to individuals, but it is difficult to describe, and there is less evidence for existence of a general tactile language that all individuals would agree with [Jansson-Boyd 2011]. The importance of learning and familiarity to cultural agreement on meaning has been barely looked at [Swerdfeger 2009].
More research is clearly needed. Our own view is that some tactile elements can be consistently understood, but far more will be personally interpreted. The beauty and power of active haptic interfaces is that individualized approaches are possible, and solutions that allow and support users in easily creating, assembling or discovering their own tactile language for their personal tools are the most promising. To this end, tools for customization by end-users, rather than expert designers, are another way to both understand perceptual dimensions [Seifi et al. 2014, Seifi et al. 2015] and move toward assisting users in “rolling their own.”
Facets
We introduced the notion of facets and schemas in Section 3.3.3 as a way of conceptually organizing, browsing and curating haptic sensations more generally. Five validated haptic facets elaborated there are physical, sensory, emotional, usage, and metaphors [Seifi et al. 2015] (Figure 3.2).
Here, we look at facet-based design as a language-grounded approach that deliberately builds on multiple sense-making schemas in users’ minds. Specifically, faceted interfaces use this multiplicity of schemas to facilitate comprehension of interface concepts, as well as navigation and search for items according to their various properties [Fagan 2010]. For example, VibViz, built around the five abovementioned vibrotactile facets, is an interactive visualization of a library of 120 vibrations. Without any haptic background, users can quickly navigate the library by flexibly moving between vibration descriptions in various facets [Seifi et al. 2015].
3.4.3 Tools
The range of tools available to haptic makers span software and hardware domains, to use for browsing, prototyping, authoring, and evaluating.
Content Collections
Libraries of effects were the first kind of software tool to achieve any kind of broad dissemination, coordinated with hardware platforms that became available for more widespread develompent. These software collections support developers by providing examples to browse, and supporting faster, easier programming and customization for sketching and refining. The UPenn Texture Toolkit contains 100 texture models created from recorded data, rendered through VT actuators and impedance-type force feedback devices [Culbertson et al. 2014]. The HapticTouch Toolkit [Ledo et al. 2012] and Feel Effect library [Israr et al. 2014] control sensations using semantic parameters, like “softness” or “heartbeat intensity,” respectively. Vibrotactile libraries like Immersion’s Haptic SDK [Immersion 2016] connect to mobile applications, augmenting Android’s native vibration library. VibViz [Seifi et al. 2015] structures 120 vibrations using a multi-faceted organization. Force feedback devices have software platforms like CHAI3D [CHAI3D 2016], H3D [H3DAPI 2016], and OpenHaptics [Geomagic 2016].
Hardware Platforms
Haptic hardware prototyping used to be really hard. Even products like Phidgets [Phidgets 2016], which lowered barriers by sourcing physical interaction widgets and giving access to them from standard computing platforms [Greenberg and Fitchett 2001], did not help force feedback designers because of the need for fast, low-latency refresh rates and high quality hardware. Similar problems applied to making vibrotactile displays do more than make annoying buzzes. Actuators capable of displaying more diverse sensations were the exclusive province of expert engineers.
The world has changed. Emergent mechatronic prototyping platforms, as well as the takeoff of a “Maker” mentality and a new ease of quick turnaround hardware component outsourcing, have radically altered the landscape for hardware
