Last summer I began using PowerPoint to depict user interfaces and narrative user interactions. Turns out PowerPoint is a great tool for this, specifically because it is easy to use to piece together a series of user interface ‘states’ that reflect a narrative user story, re-order them as necessary, and then present them on screen, or e-mail the file to a group of stakeholders. What’s more, individual or grouped elements can be animated in a variety of ways, so that during a presentation, one can demonstrate user interactivity in a way that comes much closer to how an actual version of an interface could work.
Much of PowerPoint’s merit comes with ease of use; many of the basic techniques it requires to get up and running take maybe an hour to figure out on one’s own, even without a detailed explanation of how it works. One aspect of working with PowerPoint that did end up taking me some time to learn was working with animation.
There are two kinds of animation you can apply to objects on a PowerPoint slide: Effects and Motion. Effects applied to an object cause it to appear or disappear (by fading in or wiping out, for example), or display emphasis (such as color change, spinning, or blinking effects), while motion is used to move elements around along a vector path within the confines of the slide. All animations are triggered either by a ‘click’ or a previously occurring animation. This latter type of animation trigger makes it possible for several objects placed on a slide to be animated at once – either in parallel or in sequence – which can yield some pretty involved animation sequences. This also leads us to a peculiar characteristic of PowerPoint, where complex animations are possible using drastically simplified and consolidated user tool conventions.
The speed at which the motion animation (as well as a handful of Effects) travels is configured in durations. That is, regardless of how much vector path one ends up drawing out for a motion animation, one defines the speed of the animated effect by setting a duration in seconds. This ‘Speed’ duration is how much time your animated element takes to get from point A to point B. Curiously, this might very well translate to different actual velocities depending upon the length of your motion paths. For example, say you assign parallel motion animations to two different elements with a straight path on the same slide with the same ‘Speed’ setting, except you make the path for one of the elements (Element A) longer than the other (Element B). In presentation mode, although both motion animations start at the same time, Element A will appear to travel faster than Element B because it has more distance to cover in the same duration.