What is the recommended design pattern for a CAD application, where the view is a scene graph structure?

Given a CAD drawing data structure and a scene graph-based visual representation of it, what is the best software engineering practice when it comes to the data-view decoupling?
My dilemma is, in the case of Javafx:
do I create a data structure, that represents the cad drawing and update the corresponding view,and vice-versa: update the data if the user manipulates the view, or simply store the data in the view itself?
Since the scene graph tree seems fit to store and show the same nested, parent-children data structure as a cad drawing, with its layers and entities, how about using it as the data structure itself, without an underlying data object?
Or is this lack of decoupling a bad idea?