Tag Archives: interaction design

Hunting for the optimal prototyping tool

This is a summary of my experiences with different tools for and approaches to prototyping. Prototyping is, eventually, a central area of work for interaction designers, information architects and people with other roles in the software development process.

Why prototyping?

Why bother? The aim of prototyping is to simulate the behavior of digital artifacts before any real development effort has had to be invested. This is driven from the insight that changes get more expensive the later in the development process they are realized – and anyone who has worked in software development knows that changes are inevitable. Change requests surface whenever you walk your project team through a design (no matter on which level of development you are right then). Requirements for an optimal prototype can be derived from this insight: Prototypes musts be

  • fast to create (with little effort)
  • easy to change
  • close to what will actually be built later
  • good to communicate (i.e. in a file format that can at least be viewed by the project team members, better even annotated)

With interactive products à la Web2.0 a new approach to prototyping becomes necessary – thinking in static pages doesn't help anymore as pages or elements thereof can look totally different based on system state (e.g., user unknown / known, but not authenticated / authenticated) or on user action (user has finished an action successfully / an error has occurred). It makes sense to introduce modular design into the prototype already – it'll be the basis for the technological realization anyway. This way, the interaction designers have vast degrees of freedom to have modules react onto events in other modules or to have them ignore other events. Based on this, another requirements becomes clear: the tool must support a modular approach to prototyping.

Prototyping techniques

Based on the goal you want to achieve, you can differentiate horizontal and vertical prototypes (assuming you've got limited time). Horizontal prototypes illustrate a website or an application in its whole width, but offer little or no functionality once you start drilling down. Vertical prototypes in most cases show only very rough illustrations of wide areas of a site or an application, but in limited areas, they provide a very deep and detailed view into the site's or app's depths.

If you're about to create a prototype for a usability test of a specific function, in most cases you'll want to build a vertical prototype illustrating this function in depth – and all the surrounding areas only very sketchy. If you'd like to explore the navigational behavior across a whole site, you'd rather build a horizontal prototype with very limited deep functionality.

You can create electronic or paper prototypes. Paper prototypes have got a number of advantages – they're fast to create, can be changed right in interview sessions with test participants, and because they are intentionally not finished, they invite people to playfully interact with them. They can be extremely helpful in very early project phases, because usually that's when the last requirements are being negotiated. The big drawback of paper prototypes is that you'll have to create recurring modules as often as they occur. Also it's difficult to hand them on or to document them.

Electronic prototypes usually have a more polished appearance about them. This can be a disadvantage when it keeps test participants from voicing change requests – because they could think the solution is already near completion. In addition, the participants cannot directly interact with elements of the prototype. On the other hand, a modular approach can (more or less) be realized, and you can hand on designs to the project team. Documentation is a breeze too.

HTML is quite well suited for creating interactive prototypes – if you're savvy enough and / or got the right tools. A nice example is Adobe Golive. Golive allows you to work with objects and recurring elements that can be defined outside the page. It's relatively close to development and the target system, which can become a drawback as well – when the prototype is used as the starting point for developing the actual system. You should by no means fall into that trap; otherwise Alan Cooper's scar tissue will be created: Code that has been adapted over and over again, that is not elegant anymore, and that's by no means easy to maintain.

Of course you can create HTML prototypes without using tools such as Adobe Golive (or Dreamweaver) – it's just more effort. In that case you'd need an environment that can handle modules (and you find yourself deep in the actual development process), or you start creating ugly solutions based on frames within frames to let appear single pages as modules. Both approaches are suboptimal for accelerated prototyping.

I'll exclusively cover electronic prototyping tools in the following chapters.

Prototyping using electronic tools

Microsoft PowerPoint

Microsoft PowerPoint is probably the most widely used prototyping tool. As it is installed on nearly every office PC, it's got the unbeatable advantage that everyone can view a prototype created with it – and can perform edits. This leads to another question, the question of ownership. A prototype must belong to one person, and only this one person is allowed to carry out changes to the prototype. Even if this sounds like lots of work for this one person – this is the only way to ensure that the prototype is consistent within itself and reflects the current state of the discussion. (There may be exceptions to this rule if there are very strict design guide lines that are known to everyone involved in the project and if there is a top-down mechanism in place ensuring that people follow these rules.)

PowerPoint allows for fast putting together and a very rough initial arrangement of elements. Elements can be linked to simulate interactivity to a certain degree. Later, once you've been talking to engineering with a finished PowerPoint-based prototype and you've got a first glimpse onto a possible end result, you'll realize why PowerPoint is actually quite ill-suited for building prototypes: Measurements don't fit at all. You'll fit lots more onto an actual 1024×768 web page or screen than what can be displayed (and read and edited) on a PowerPoint slide. In addition, PowerPoint's scaling functions can tempt users to make elements fit on the screen that would otherwise never fit – which, unfortunately, results in  screens that cannot be built like that anymore.

Another really severe drawback of PowerPoint is that it cannot deal with modules. PowerPoint only works with copy&paste – and once you've distributed an element on 40 slides and need to go at it and change every single instance of it over and over again, you'll realize that something important has been forgotten and / or PowerPoint just isn't the tool of choice. To summarize: Not suited except for very rough idea visualization.


Denim is an innovative tool for early phases of the definition process. You can create pages and their links on different levels of detail, even simulate a certain interactivity. It uses gestures, if available also using a graphics tablet. Circular contextual menus speed up usage quite a bit. The tool, which is written entirely in Java, is available for Mac OS X, other *nix systems and Windows. Unfortunately it's got one major drawback: it's not really stable. In addition, it starts eating system resources like crazy once files become big, and the built-in HTML export functionality only works partially and produces code that, strangely, runs only on Internet Explorer. It's nearly impossible to export to PDF or just to print properly. So: promises to become an extraordinary, very innovative tool, but isn't ready yet.

Apple Interface Builder

Anyone who's got the Mac OS X developer tools (on original Mac OS X system disks or downloadable from apple.com) can use Interface Builder to create really extraordinary simulations of Mac OS X user interfaces. Simulations? No – these are actual UIs, just without logic and data structure. Guides appear automatically when you start placing elements on the pane, ensuring that the placement is in sync with the latest version of the Apple Human Interface Guidelines. Amazing! Drawbacks: it's only well-suited for application design (and only support app design really well), runs only on Macs, and saves only to the proprietary .nib file format.

Microsoft Visio

Microsoft Visio is actually a tool for creating diagrams of all kinds. It's well suited for this task, and that's what I used to use it for quite a lot. It's also used a lot to create screen design concepts. It's got the big advantage over PowerPoint that the presentation is much closer to reality; you can actually get an impression of how much content to fit onto a screen. Working with modules is possible since Visio 2003 by placing files in files (see this very helpful article over at BoxesAndArrows). Stencils can be used for recurring elements, too. Unfortunately, Visio uses a proprietary file format; it can export into a multitude of different other file and image formats, but none of them is really good. (The same applied to OmniGraffle, by OmniGroup. Unfortunately, GomniGraffle cannot place OmniGraffle files. It's available for the Mac only; Visio is Windows-only.)

Adobe Photoshop

The queen of all image processing tools is used for prototyping purposes as well. As you can combine elements in layers (and layers in folders …), you can simulate a certain degree of modularity. The great possibilities in Photoshop tend to tempt designers to create a much higher-fidelity design of the prototype that what would actually be necessary (or desirable) at a given project stage. At the end there's a rather polished design that cannot be changed as quickly. High-polished designs, in addition, can impress participants in usability tests and keep them from voicing their opinions because everything looks so "finished" already. Photoshop can export to a number of file formats. A drawback lies in the huge data files, which can hinder data exchange. If you want to rather use jpgs or pngs – to reduce the file size –, you again need a tool like PowerPoint to ensure things are viewed in sequence (e.g., in a scenario), or you'll have to create and maintain a naming convention for file names. That's why I feel Photoshop is only partially suited for creating prototypes.

Adobe Illustrator

The BoxesAndArrows article shows that Adobe Illustrator and Visio are the only two graphics tools that support modular prototyping. You create elements in files you place (as PDFs, on Windows, native Illustrator files are supported as well) in other files. If you change anything in the elements, these changes are reflected nearly instantly in the main files as well. Finished versions can be exported to PDF; you can assume that the Adobe Reader is pre-installed on nearly all systems. If – in addition – you've got Adobe Acrobat, you can create coherent presentations and, if you've got enough time, even put in links to simulate a certain degree of interactivity. A drawback of Illustrator (even in the CS3 version) is that it still cannot deal with multi-page documents (even though Freehand had this feature for so many years ago – d'oh.). This can be smoothed out using the PlugIn MultiPage (by HotDoor). Thus, you can combine complete sets of view in one file, source out and maintain individually modules and optimize the resulting exports in Acrobat. Should you also have got InDesign, you can place the finished views (or the modules) in InDesign and create design comments directly there – supporting the life cycle from prototyping to design documentation. One big disadvantage of Illustrator is the steep learning curve you encounter when getting in touch with a complex vector graphics package like this.

Axure RP

Axure RP Pro promises to be a very interesting tool – including integration into Word and HTML export. The demo I've seen recently looked impressive, but it also comes with an impressive price tag.


Personally, in terms of prototypes, I'm currently most productive in Adobe Illustrator, possibly combining it with Acrobat: fast; close enough to the final result, but not too close; modular, that is it supports fast changes; exports files to a commonly readable format (PDF) that can even be annotated with the appropriate tools (e.g. Acrobat Elements). As licenses to Illustrator are normally not available with every office PC the question of ownership of the prototype is solved as well: It rests with a small number of people who stay in control of the prototype.

(This is the translation of a post for my now inactive German-language blog from June 2006 – I've updated some small things wherever necessary.)

Designing the (AOL Phone) Box

AOL Phone Box (small image)In August 2006, AOL Germany launched the AOL Phone Box, an AOL-branded ADSL 2+ modem / router with integrated 4-port Ethernet switch and VoIP telephony functionality. When we started working on the AOL Phone Box project more than a year ago, the AOL Germany world looked quite a bit different: AOL was one of Germany's biggest ISPs, providing a huge number of customers with fast DSL Internet access (and a big number with slower narrow-band dial-up access); the web-based products like the portal, e-mail, instant messenger offered functionality on top. Now, the access business has been sold to Telecom Italia, and AOL is turning itself into a portal player, offering free e-mail, news, and other web-based services and content. Time flies …

The project had a number of goals, apart from just creating the Box:

  • Create an Internet Access Device that is simple and straightforward to set up – in order to reduce the number of support calls (setting up the access device is a major call driver).
  • Create a compelling, appealing user experience make people want to possess the box.
  • Build up in-house expertise on how to create hardware products for future projects.

After quite a bit of research, the project team decided on working with a German manufacturer, Bautzen-based Sphairon Access Systems. Sphairon had a hardware and software platform that looked very promising, and they had lots of experience working with various telecoms – they build DSL splitters, Internet Access Devices, ISDN NTBAs and other devices needed for telephony and Internet access. We started out from an existing product, but had it completely revamped to fit our ideas of what an AOL-branded device should look like. Nuremberg-based industrial design firm B/F Design supported us here – they created innovative rough designs, did fantastic renderings and great prototypes.

The Interactive Design sub-project had a couple of tasks:

  • Revamp the existing user interface to make it fit into AOL Germany's visual design language.
  • Check and improve the user flow to achieve a higher level of usability.
  • Control and manage external development and design efforts.
  • Innovate on new features and parts of the offering.

Where we were coming from

The closest relatives to our AOL Phone Box are the members of Sphairon's line of Turbolink devices. They feature quite a versatile, extendable hardware platform, but come in a rather plain, matter-of-fact shell. The IAD shown below was presented by Sphairon at the 2005 CeBIT.

Sphairon Turbolink

Likewise, the design of the configuration web interface was a bit plain, and we felt it could be improved a bit – it had to be adapted to our visual standards anyway. We therefore adopted a visual style that mirrored our AOL Germany portal design.

How we got there

First, a new shell was developed by B/F Design. It needed to reflect AOL's brand values – Human Individuality, Top Quality, Elegant Simplicity, and Inspiring Enjoyment – and look high-class. I think they did a tremendous job.

AOL Phone Box

Reversed-engineered Information Architecture for Web FrontendIn parallel, we reversed-engineered the existing browser-based configuration front-end – we created a site map containing all the places and functionality. We then compared this site map to our list of desired features and started moving functionality around, restructuring the configuration tool's organization. After deciding which functionality should be experts-only and which should be available to all users, the IA for the web configuration was finalized and wire frames for a number of screens were created to illustrate the arrangement of elements on the UI. To get the web configuration tool to sport our visual style, we developed a visual design style guide especially for this product and delivered all the necessary assets to Sphairon, together with a couple example screens. We then moved on to defining two new parts of the AOL Phone Box experience: the "Einrichtungsassistent" (setup assistant) and the "CD-Intro" (CD-based introduction to the product). The customers should use the CD-based introduction to get the cabling right; once everything had been connected properly, the setup assistant (resident on the hardware) should take over and lead the user through the basic configuration of the product. To the user, this two-platforms approach should feel like one seamless process. During the interaction design process, we especially focused on possible error conditions: We analyzed them and either tried to circumvent them, or we used them to help users identify what might have been the cause of their issues and to help them out (again, a way to reduce Call Center volume and thus cost).Extremely close collaboration in the team and with our development partner Sphairon helped us make great progress, and we took great pride in seeing our ideas get realized and the designs getting closer and closer to what we had envisioned.

Design and Usability Evaluation

After some time of working on a project, you lose the ability to actually assess a solution's quality. So, at two points in the development cycle, we conducted usability evaluation measures with our partner HCiconsult. Early on (with a rough version of the UI in place), a heuristic evaluation was done. Later, when the development was 2/3 complete, we had a usability test conducted with seven test participants. Both measures showed we were on the right track, but of course there was still room for improvement. The findings were discussed and incorporated into the design iterations.

When we started to think about packaging and printed material, we realized that it would be highly desirable to provide a consistent wording throughout all materials – be them on the configuration UI of the box, on the CD, on the packaging or on leaflets. So we provided the necessary wording and operated as wording QA for the electronic manual. While this was quite an extra work package, it nicely followed the philosophy of an end-to-end design responsibility.

AOL Phone Box packaging

A challenging and rewarding project

In the end, the Interactive Design team had contributed in the following domains: For Interaction Design, we had contributed Information Architecture, user flows, and screen layouts. As for Graphics Design, we had created Visual design standards and provided the graphics assets for the development partner. Wording of all customer-facing texts including Web Interface, packaging, and manual had been provided by us. We had had our say in the design of the packaging, and of course there had been the final sign-off of all materials by the Director Interactive Design.

The AOL Phone Box has proved to be quite a success. The expected benefits were realized, the customers love it, and we have not only delivered a fantastic product, but also learned a lot – and had quite a bit of fun.

Interaktivni festival IF 2006 ? October 26, Ljubljana, Slovenia

logo_if.gifYesterday I paid my first visit to Slovenia's capital Ljubljana[GP:Ljubljana] to attend the "Interaktivni festival IF 2006" and to give a talk on the AOL Phone Box. Vuk ?osi?, whom I had met at the euroGel 2006, had asked me whether I wanted to deliver the talk and share some insights and information on a successful interaction design project, and I had decided to use the AOL Phone Box as an example. The AOL Phone Box is an ADSL 2+ modem with built-in Voice-over-IP (VoIP) functionality. It's based on a hardware platform from our hardware partner Sphairon; we have done the interaction design for the configuration Web Interface, the CD-based connection assistant and the built-in setup assistant. I'll go into more detail on this nice project in a later post. Vuk had asked me to prepare a 30-minute talk and be open to q&a for another fifteen minutes. I happily obliged, and we had a great session with lots of questions from the audience as to the design methodology, our usability evaluation methods, and metrics we would be using to determine the (economic) success level of the product. I feel grateful and deeply honored to have been invited to give this lecture, and I enjoyed my stay in beautiful Ljubljana with lots of highly motivated Internet professionals.

Mensch und Computer 2006 ? September 3?6, Gelsenkirchen, Germany

Gelsenkirchen[GP:Gelsenkirchen], in Germany's far West, hosted this year's "Mensch und Computer" ("Man and Computer") conference, the most important conference for the German-speaking usability community. As usual, A UPA track accompanied the research and science paper sessions. Again (like in 2004 and 2005), the UPA track featured the sessions I found most interesting – there were a presentation of a non-intrusive remote usability method, some important discussion on whether or not usability professionals had to get a certificate, and the founding session of a new workgroup for in-house usability consultants.

Discussing the Certification issue

Of the invited talks, I much preferred the one by Prof. Dr. Matthias Rauterberg, TU Eindhoven. Back in 2000, I interviewed Mr Rauterberg for my thesis on Joy of Use. I must confess it was quite difficult to stick to my prepared set of interview questions – actually, I didn't manage and got a long, very interesting and though-provoking, but not too focused interview out of it. Now, Mr Rauterberg's speach on "Usability in the Future – Explicit and Implicit Effects in Cultural Computing" tackled Eastern and Western design philosophies, C.G. Jung's archetypes, who we thought the 21st century Copernicus could be, and Alice in Wonderland. I guess he left most of the listeners puzzled, but some found harsher words. I myself must say I quite enjoyed it. Overall, the conference didn't present any surprises. The talks, papers, and posters were ok, but not as inspirational or innovative as I had hoped. It might be a good idea to switch from an annual schedule to every second year to give researchers and practitioners more time to prepare better material. But maybe I've just been spoiled by the euroGel conference experience just two days before.

The Fachhochschule Gelsenkirchen (University for Applied Science)