A common use case of augmented reality (and virtual reality too) is the visualization of models that belong in the real world but aren't there yet. For architects, these may be called preconstruction renderings. For interior designers, they are called visual presentations. Virtual reality is useful when you need to transport the user to this other space virtually. Augmented reality is useful when the user is already in the space and you want to show them something different, to augment the environment.

In addition to design, this also applies to marketing and sales. Ikea and Wayfair, for example, are furniture retailers who offer AR-enabled mobile apps that let you visualize potential furniture purchases, placed in your home where you might want them.

In this chapter, we will build an AR app that lets you decorate your room with personalized framed photos. You'll be able to select a frame from a shopping catalog, then pick from a gallery of photos and place the framed photos on the walls of your room.

For this project, we will mix things up a bit compared with other projects in the book. We start with a Microsoft HoloLens implementation first, since this is a more natural application of wearable see-through AR. Then we will port it to iOS and ARKit. Then we will port it to Android and older iOS devices using Vuforia.

We will learn how AR devices scan your room and create a spatial map mesh. We will then learn how to use this mesh model in augmented reality. The project also shows you how to build 3D user interfaces, including button tools, modal tools, and menus.

In this chapter, you will learn more about the following:

• Building a 3D user interface and elements from scratch
• Understanding spatial mapping for AR
• Using the Microsoft Mixed Reality Toolkit InputManager and Unity GestureRecognizer
• Additional software design patterns, including action-command, inheritance, and input events
• More about using ARKit and Vuforia