At today's WWDC, Apple demonstrated a ($ 799.99 at Cricket Wireless) to measure real objects.. See the video below. When you can use your iPhone
Guess what? You can already do so thanks to a variety of third-party apps, many of which debuted last year, when Apple unveiled its ARKit software.
For example, there is Laan Labs Air Measure (formerly AR Measure), which works much like iOS Measure. You simply aim your camera at a starting point, tap a button, move it to the end point, and then tap again. As you move, a virtual tape measure appears.
Air Measure can also measure the vertical height of an object, generate a 3D cube around an object (for example, to determine the size of the shipping box), and help you create an accurate 2D floor plan. It is a free app.
Conclusion: You do not have to wait for iOS 12 to add an augmented reality tape measure to your iPhone. However, you need an iPhone that is ARKit-compatible, that is, anor later.
Search for "AR measure" in the App Store and you will find many others whose prices range from free to about 10 €.
This is an evolving story. See CNET's WWDC live blog here.