Top
You can view your complete drawing in the current viewport.
This is useful if you have been viewing a lower level and want to quickly restore the complete drawing to the viewport
To view the complete drawing in the current viewport:
1. Click Structure and then, in the Parts group, click 
View.
View.2. Click Top.
Top.The chosen viewport is redrawn to show all the parts of your drawing. The name of the top part is displayed in the top-left corner of the viewport.