Why does my model look sectioned?

Does your model section itself when you try to navigate through it? 

One of the most common reasons for this is spurious objects located away from the actual model.  To see if there are objects "floating in space" in your model, do a Zoom All (Page Up) of your screen:

If this is the problem the best way to fix it is to have whomever is responsible for the floating objects to remove them from their model.  If you do not have time and need a quick fix, the "Hide Unselected" tool is perfect for this.
Zoom into your model.
Use the Select Box to window around the model you want to keep.

Click on "Hide Unselected" under the Home tab

Your model should now only display the objects that matter and function better during navigation.

If this does not fix your issue then there is additional information about clip planes on this website: Autodesk Beyond Design Blog