We are currently developing an AR app. Mostly for an experimental project. The goal is very simple, 1. detect ground plane form device camera video, 2. showing a grid based on that plane, 3. when the user tap on the grid the object appears with an animation. 4. The app must work in most of the android device (Starting from KitKat or Marshmallow) After a couple of days research, I found a couple of solution to solve this problem. 1. Google AR - Wich doesn't support most of the device (this is 30th April 2018). 2. Paid SDK - On the other hand, any SDK that is able to detect ground plane is paid version also they used SLAM (Simultaneous localization and mapping) I found some resources to use gyro and accelerometer to place an object in the live video. I experimented with those and found they are not that perfect. I also found about OpenCV which is actually open source and has the ability to process images but the one that integrates with unity is $70 probably (My goal is to make this app using an opensource library) Now here is my question 1. Is there any open source SLAM SDK? 2. Is there any other way to detect the ground plane in unity? 3. Is there any open source SDK that alow tracking inside unity?