Just a Line lets anyone use cutting-edge ARCore technology for the simplest possible purpose: to draw a line.

Drawing is a basic human activity. For over 50,000 years, we’ve drawn on cave walls, paper, sand, sidewalks, and more. And with AR, the world becomes a canvas.

It’s early days for AR, and Just a Line is simply a proof-of-concept, so we radically limited what the app can do. There’s only one color, and you can’t save or edit drawings. But because the app is so simple, it’s also a great starter project for developers looking to try AR. The code is open-source and available on Github, so anyone can use it to build their own AR apps.

Google ARCore enables AR in regular Android devices - no extra hardware required. It uses three key technologies to integrate virtual content with the real world as seen through your phone's camera: 1) Motion tracking allows the phone to understand and track its position relative to the world. 2) Environmental understanding allows the phone to detect the size and location of flat horizontal surfaces like the ground or a coffee table. And 3) light estimation allows the phone to estimate the environment's current lighting conditions. Just a Line was built using version 1.0 or ARCore, which is supported on the latest Android devices.

The Just a Line app hit the #1 trending spot in the Play Store. Users posted over thousands of creations with #justaline. And press covered with headlines like, “The tables have turned: Our favorite new AR apps are Android exclusives”.