The Zoom Mouse option (a.k.a. Mouse Zooming, dynamic zooming) is another convenient method for zooming in or out. To use Zoom Mouse:
Select the Zoom Mouse option.
Press and hold the left mouse button.
Move the mouse up (to zoom in) or down (to zoom out) while keeping the left mouse button pressed.
Release the left mouse button when the zoom is satisfactory.
To exit the Zoom Mouse option, use the Escape key, or right-click and select Done.
If you have a mouse with a wheel, you can quickly zoom in or out by moving the wheel forward or backward.
Note that Zoom Mouse always zooms the model about the center of the view. To zoom in to a specific area of interest, you may find it necessary to use Zoom Window rather than Zoom Mouse, unless the area you wish to zoom is already at the center of the view.
Zoom Mouse is available in:
The Zoom sub-menu of the View menu
The Zoom toolbar
The default right click menu