Using these display specifications is similar to using a camera. The following sketch illustrates the concepts of focus point, viewpoint, and viewing distance, discussed below.
The viewing direction is established by a vector directed from the viewpoint to the display coordinate system origin. Issue the /VIEW command to define the position of the viewpoint in the display coordinate system.
Use this shortcut to pan, zoom, and rotate a graphics display:
Press the CONTROL key and hold it down. You are now in Dynamic Manipulation Mode. Notice that the cursor assumes a different shape.
While holding the CONTROL key down, use the mouse buttons to manipulate your view of the display.
Release the CONTROL key to exit Dynamic Manipulation Mode.
You can also remap your mouse buttons to match the operation (in dynamic mode only) of other programs (/UIS,BORD,LEFT,MIDDLE,RIGHT).
To rotate the graphics display about the screen axes or about the global Cartesian axes, issue the /ANGLE, /XFRM commands. (The right-hand rule defines positive angular rotation about any axis.)
The /VUP command determines the "starting" orientation of your
display. For example, with the viewpoint and rotation at their default settings,
/VUP,WN,X orients the display such
that the positive X axis is vertical pointing upward, Y is horizontal pointing to
the left of the screen, and Z points out of the screen.
The focus point is that point on your model that appears at the center of your windows. You can define or redefine the focus point (in terms of the global Cartesian coordinate system) via the /FOCUS command.
The command also enables you to translate the focus point along the screen axes or along the global Cartesian axes.
The viewing distance represents the distance between the observer and the focus point, and determines the magnification of your image. Smaller viewing distances magnify the image (zoom in), and larger distances shrink the image (zoom out). Issue the /DIST command to change the viewing distance.
Anytime that you change the viewing distance or focus point, your explicitly-defined settings become fixed; that is, automatic scaling or centering of the image are deactivated for subsequent displays. (Fixed parameters are preceded with an asterisk in the legend column of the display.)
To restore automatic scaling and focus, issue the /AUTO command.
By default, your display is automatically scaled and centered such that the image of your model just fills your windows. To fix these automatically-generated scale and focus settings, issue the /USER command.