https://thenextweb.com/apple/2018/06/04/apples-new-measure-app-is-like-an-ar-ruler-for-your-iphone/

At WWDC 2018, Apple announced a new app as part of its AR offerings called Measure. It’s exactly what it sounds like.

By simply using your phone’s camera, you can measure the size of real world objects. Apple exec Craig Federighi showed off a demo where he measured the dimensions of a suitcase and photo by just pointing his device at the object. The app shows a dotted line acting as virtual measuring tape of sorts, and you create virtual anchors on the object to measure other dimensions as well.