This is probably an insanely hard question. So far ARKit works with 3D models which are built in 3d modelling software. I was wondering if there was a way to use iPhone camera to scan 3d object (let's say a car), then use it in ARKit.
Any open source projects available which do this on other platforms or iOS?
You are looking for software in the "photogrammetry" category. There are various software tools that will stitch your photos into 3D models, but one option is Autodesk Remake. There is a free version.