An important emerging application of Augmented Reality is professional and industrial training, including equipment maintenance and how-to manuals. Over the years, traditional paper documents have given way to digital multimedia. First came DVDs, then web-based online docs, and then dedicated mobile apps. The next step will be the adaptation of more interactive and immersive media using AR.

In this chapter, we show you how to build an app that guides someone in changing a flat tire on their car, using step-by-step instructions. Labels and explanations will be superimposed on the real-world objects. You just click Next through the steps.

For this project, we will start with an existing web-based tutorial from wikiHow, How to Change a Tire, convert it to a regular mobile app, and then augment it with Augmented Reality features. This mimics similar real-world business situations.

We will also use this as an opportunity to introduce important programming patterns which Unity developers favor. These patterns, including abstract classes, inheritance, event observers, and serialized data, will make your code cleaner, more flexible, and, in the long run, easier to maintain. If you're new to programming, just follow along. If you are an experienced developer, you may appreciate that we're taking the examples up a notch.

This project is split across two chapters. In this chapter, we will build a conventional non-AR version of the app. The next chapter will convert the project to AR. In this chapter, you will learn about the following:

• Software design patterns
• Screen space UI (user interface), layout, and scrolling
• Importing data from CSV files
• Refactoring your app to use Unity events and class inheritance
• Using images, video clips, and video player

Our implementation targets Android mobile devices, but does not require them. If you prefer to develop for standalone (PC or Mac) desktop, that will work too.