Hi XR friends!
Wanted to share with you and if you have any questions, I’ll try to answer them.
We created a ball bouncing game for Spark AR using Cannon.JS library. https://schteppe.github.io/cannon.js/
You can have a try in Instagram: http://bit.ly/2HhiKar
We had problems understanding quaternion vectors but resolved it understanding how was the bouncing behavior.
We reduced value of gravity to not be so real, because would be really difficult to make points.
Hope you like it!