USDZ always open in preview

Hi I am trying to use USDZ from remote source within swift app (not web) and it always opens up in the preview, am i misunderstanding that this is replacing scn files as it's already contained scene.

I also tried to keep my code simple,

do {
            let scene = try SCNScene(url: URL(fileURLWithPath: "http://url.usdz") , options: nil)
           
            // Set the scene to the view
            sceneView.scene = scene
        } catch {
            print("ERROR loading scene")
        }

just create a let to the url and then open in ARScene and it just errors in the console

I appreciate its new but I need more documenation and support to release in Autumn in 2018