I've seen many lists on the internet that includes many 'ities' (maintainability, scalability, portability, etc), but I'm not sure if animations, screen transitions, and similar features are functional or non functional requirements.
Are animations and other eye candies considered non-functional requirements?
requirements;user experience;usability;animation
Animations can be an extremely important part of the user interface. They communicate or hint at things a user can do, guide the user through the application or help build up a well defined mental model of the application inside the user's head. Consider the classic iPod interface, where screens slid from side to side to signify the navigation through a hierarchy. ipod interface http://c2499022.cdn.cloudfiles.rackspacecloud.com/wp-content/uploads/2006/05/iPod%20audio%20interface.jpgNothing communicated this better than an animation, which helped build a mental model of the navigation tree which greatly improved usability. Imagine the same interface without animations, where screens would simply change without transition; it'd be much harder to understand intuitively. Since I'd consider a good UI to be pretty essential to an application (depending on the kind of application obviously), animations are not just eye candy, they're part of usability.If you just throw animations on top of a general GUI with no clear purpose, they're pretty superfluous of course.Having said this, usability is typically considered a non-functional requirement.