The distance from the front to the back of a 3D view is its Display Depth. This depth is bounded by clipping planes, unless they have been disabled in the View Attributes dialog. When clipping planes are on:

• The front clipping plane is nearest the viewer.
• The back clipping plane is farthest from the viewer.

Elements in front of the front clipping plane, or behind the back clipping plane, are not displayed in the view. This applies even if they are within its viewing area, regardless of how far the view is zoomed out. In other words, the front and back clipping planes define a "slice" of the total volume of the design cube. Only elements located within this slice can be displayed in a view. You can change the position of these front and back clipping planes with the Set Display Depth view control, or when you fit a view, with Expand Clipping Planes turned on (this setting causes the display depth to be adjusted, along with the window area, so that all elements are displayed).

When a clip volume has been applied to a view, and Clip Volume is enabled (in the View Attributes dialog), then this is the maximum volume of the design cube that will be displayed in that view. Clipping planes can be set that reduce this volume, but they have no effect if they are set outside the clip volume.