Applying post-processing to SceneKit's Scene and saving it to a USDZ file

I am fairly new to 3D model rendering and do not know where to start.

I am trying to, ideally with ARKit & RealityKit or SceneKit, do a scan of an environment. This includes:

Applying realistic textures to the model. Being able to save it as a .usdz file (to be able to open it within the App itself) Once it is save do post-processing measurements within the model. I would prefer to accomplish this feature by using a mesh, instead of the pointCloud that is used in the sample project of apple. Would this be doable using Apple's APIs and on a mobile device or would it be necessary to use a third party program?

I have managed to create a USDZ file using SceneKit's .scene.write(to:,delegate:) method. However the saved file is a "single object" and it is not possible to use raycasting to do post-processing measurements in the model.