Zooming using a mouse with a wheel

Each rotation of the wheel away from you zooms out .8 times; each rotation toward you zooms in 1.25 times.

To zoom using a mouse with a wheel    

    Rotate the wheel away from you to zoom in or toward you to zoom out.

Customize the mouse wheel
Settings for the mouse wheel can be customized to accommodate your work style using the ZOOMWHEEL (wheel direction), ZOOMPERCENT (display accuracy for curved entities), and ZOOMFACTOR (zoom factor for the wheel) system variables.