From Jason Snell’s story for Macworld on trying 3D Touch at Apple’s September 9 event:

Every time I intended to use 3D Touch to “push” an icon on the iPhone home screen, the feature activated and a contextual menu popped into view, accompanied by a tiny vibration to indicate that I had succeeded with my gesture. The extension of that gesture–sliding my finger or thumb down to the right menu item and then letting go–felt natural after a single try.

When I used the iPhone without attempting to enable 3D Touch, it didn’t enable. When I tried, it worked. In Messages, I was able to push on a message preview and receive a “peek” at the full message, with accompanying vibration. When I wanted to commit to opening that message, I pushed a little harder and was greeted with another vibration as the full message “popped” in.

More than haptic feedback and shortcuts, it sounds like 3D Touch will fundamentally alter the navigation experience of iOS. Several iOS 9 features (new app switcher, back button, Universal Links) make more sense in the context of 3D Touch, too.

I missed this story by Josh Tyrangiel for Bloomberg Business on how Apple’s design team approached the idea of bringing pressure sensitivity to the iPhone’s screen. I liked this bit with Craig Federighi:

But in lieu of the usual polite deflection, Federighi picked up an iPhone 6S and explained one of 3D Touch’s simpler challenges: “It starts with the idea that, on a device this thin, you want to detect force. I mean, you think you want to detect force, but really what you’re trying to do is sense intent. You’re trying to read minds. And yet you have a user who might be using his thumb, his finger, might be emotional at the moment, might be walking, might be laying on the couch. These things don’t affect intent, but they do affect what a sensor [inside the phone] sees. So there are a huge number of technical hurdles. We have to do sensor fusion with accelerometers to cancel out gravity—but when you turn [the device] a different way, we have to subtract out gravity. … Your thumb can read differently to the touch sensor than your finger would. That difference is important to understanding how to interpret the force. And so we’re fusing both what the force sensor is giving us with what the touch sensor is giving us about the nature of your interaction. So down at even just the lowest level of hardware and algorithms—I mean, this is just one basic thing. And if you don’t get it right, none of it works.”