Copyright Goodheart-Willcox Co., Inc. Chapter 4 Understanding Three-Dimensional Coordinates and User Coordinate Systems 99 Move the pointer to each of the other two UCS icon axis grips and note that a similar menu is displayed. Each axis of the UCS can be rotated in the same manner using the appropriate axis grip. Additional UCS Options Additional options for changing the UCS are discussed in the following sections. Some of these options can be selected from the UCS icon shortcut menu displayed by right-clicking on the UCS icon, shown in Figure 4-19, or by accessing the Coordinates panel in the Home or Visualize tab on the ribbon. All of the options discussed are avail- able when entering the UCS command on the command line. NOTE NOTE Keep in mind that many of the procedures discussed in the following sections can be accomplished using the dynamic moving and rotating functions of the UCS icon grips. Selecting Three Points to Create a New UCS The 3 Point option of the UCS command can be used to change the UCS to any fl at surface. This option requires that you fi rst locate a new origin, then a point on the positive X axis, and fi nally a point on the XY plane that has a positive Y value. See Figure 4-25. Use object snaps to select points that are not on the current XY plane. After you pick the third point—the point on the XY plane—the UCS icon changes its orientation to align with the plane defi ned by the three points. The 3 Point option is available in the UCS icon shortcut menu. PROFESSIONAL TIP PROFESSIONAL TIP When typing the UCS command, enter 3 at the Specify origin of UCS or [Face/NAmed/ OBject/Previous/View/World/X/Y/Z/ZAxis] World: prompt. Notice that the option is not listed in the prompt. UCS Ribbon Home Coordinates Visualize Coordinates 3 Point Type UCS Move pointer over axis grip to display shortcut menu A B UCS rotated to new orientation Figure 4-24. Using the UCS icon axis rotation options. A—The Z axis options appear after moving the pointer over the Z axis grip. Pick the Z Axis Direction option to set the direction of the Z axis. B—The new UCS after rotating the Z axis. Note that the other Z axis options can be accessed by pressing the [Ctrl] key.