How to turn on the rear camera in the PlayCanvasAR ?
It should automatically ask for permission when you start the app. Are you using the AR Starter Kit from Will? https://playcanvas.com/project/481413/overview/ar-starter-kit
It does rely on having a particular version of Chrome or higher if running on Android.
I agree the permission and open the front camera by default；
By default, the code should prefer the rear camera.
You may need to make some changes to the code related to https://github.com/jeromeetienne/AR.js/issues/86