Zoom Realtime
The Realtime command zooms in and out as the left mouse button is held down and the mouse is dragged up and down in the plot or 3D view window. The 3D view can also be changed by adjusting the values in the Environment properties Camera page.
Enter Zoom Realtime Mode
To enter zoom realtime mode, click the View | Zoom | Realtime command or the 
button. The cursor will change to a 
to indicate that you are in zoom realtime mode. Hold down the left mouse button and then drag up or down in the window to zoom in or out. As you drag the mouse up, the screen is zoomed in. As you drag the mouse down, the screen is zoomed out.
Exit Zoom Mode
Click another tool or press the ESC key to end zoom mode.
Zoom Realtime With A Wheel Mouse
You can use a wheel mouse to zoom realtime in the plot window, 3D view window, and grid editor. You can use a wheel mouse to pan in the plot window and grid node editor. Rotate the wheel forward to zoom in, or rotate the wheel backward to zoom out. Hold down the wheel button straight down, and the cursor will turn to a closed hand. When the cursor is a 
, drag the mouse to pan the plot window. Be sure to click straight down with the scroll wheel. The zoom is changed so that the cursor location remains on the screen.