I have sceneform sample hellosceneform app with its arFragment and want to add object on custom coordinates. For this, as I understood, I need to have a session to add an Anchor on it then create a Node etc. But when I run arFragment.getArSceneView().getSession() to call createAnchor() on it, I get null. How to get not null session?
P.S. arFragment is standard hellosceneform's ux fragment:
arFragment = (ArFragment) getSupportFragmentManager().findFragmentById(R.id.ux_fragment)