One of the great benefits that AR brings to end users is that it is now possible to preview certain objects in the real world. For instance, when you buy a new sofa, you might want to see what it looks like in the real world. Of course, it was possible to implement features such as this in iOS 11 using ARKit, and many developers have, but it wasn't as easy as it could be.

iOS users can preview content using a feature called Quicklook. Quicklook can be used to preview certain types of content without having to launch any specific applications. This is convenient for users because they can quickly determine whether a particular document is the document they are looking for by previewing it in Quicklook.

In iOS 12, Apple added the USDZ file format to the content types that can be previewed using Quicklook. Apple's USDZ format is a 3D file format based on Pixar's USD format that is used to represent 3D objects. Using Quicklook for 3D models is not just available in apps, ARKit Quicklook can also be integrated on the web. Developers can use a special HTML tag on their web pages to link to a USDZ and Safari will display the model in an ARKit Quicklook view controller.

Before you implement your AR gallery, it's a good idea to get a feeling for how AR works on iOS by implementing the ARKit Quicklook view controller to show one of the models that Apple provides on https://developer.apple.com/arkit/gallery/. To download a model you like, all you need to do is navigate to this page on your Mac and click on an image. The USDZ file should start downloading automatically.