© 2010 Autodesk
Introduction to the Navisworks 2011 .NET API
Main API Classes
Autodesk.Navisworks.Api.Application
Autodesk.Navisworks.Api.Document
Autodesk.Navisworks.Api.Model
Autodesk.Navisworks.Api.ModelItem
[Application]+--[Document], [Document]+--[Model], [Model]+--[ModelItem].png
These are the class names.
Note how they related to each other.