In the world we live in, we are constantly using new and different software. When the newest social media app hits the ground, we want to try it out. Quite often, when we load these new apps, we almost instantly know how they work. This is very much due to user interface design.

According to Wikipedia "user interface design or user interface engineering is the design of user interfaces for machines and software, such as computers, home appliances, mobile devices, and other electronic devices, with the focus on maximizing usability and the user experience."

Good interface design is both an art and a science, the core being the ability to anticipate the user's needs and design a system that helps nudge the user down the path they are on. With this understanding, we need to make sure that the necessary elements to accomplish the task are available. These elements can be informational, interactive, or visual in design, or combinations of these. A good interface design is clear, easy to grasp, and feels natural to its user. Ideally, a good interface design is almost invisible to the user; no, this does not mean that the user cannot see it, but that the interface feels so natural that they do not realize they are using an interface.

There are many interface elements that we use every day, and unless you are an interface designer, you likely take them for granted. We have used many of these so far in this book. Here are some of the elements that Unity uses:

• Buttons: This lets the user know that there is an action when it is used
• Input Field: This allows the user to enter text
• Toggles: This is a two-position button; on/off states are common
• Slider: A slider allows the user to adjust a parameter by sliding a bar
• Dropdown: This is an interface element that allows the user to choose from many options listed in some order

According to the U.S. Department of Health and Human Services, interface elements can be broken down into these categories:

• Input Controls: Buttons, text field checkboxes, radio buttons, dropdown lists, list boxes, toggles, and date fields
• Navigation Controls: Breadcrumbs, sliders, search fields, pagination, tags, and icons
• Informational Controls: Tooltips, icons, progress bars notifications, message boxes, and modal windows