When you declare a notebook to another notebook, you establish a hierarchical relationship between them. The current notebook becomes a child of the notebook to which it is declared. You can set the global datums and dimensions of the parent notebook to govern those of the current notebook.

You must create global references since the system does not create them automatically. A prompt appears when you declare the notebook, Duplication of global symbol symbolname. Delete local version? [No]. If you want a global reference, enter Yes. The system then deletes the symbol name from the current notebook and replaces it with a cross-reference pointing to the notebook in which the symbol resides. If you enter No, the local parameter remains independent of the global one.

If you keep a local version, you can use the same symbol name in many notebooks. For example, the Length symbol can represent the length of a beam, a shaft, and a pipe. If all of these Length parameters are completely independent (that is, modifying Length for one does not affect Length for another), the parameter name can be the same for each model.

The creation of a global reference is useful for controlling parameter values at a single location. If you modify a single parameter in a parent notebook, the system passes the modified value down through the notebook hierarchy to the associated models.

You can create as many hierarchical levels as you like. You can also declare a notebook to multiple unrelated parents.