Copyright Goodheart-Willcox Co., Inc. 188 AutoCAD and Its Applications—Advanced Exercise 8-5 www.g-wlearning.com/CAD/ Complete the exercise on the companion website. 3D Polar Arrays A 3D polar array is similar to a 2D polar array. However, the axis of rotation in a 2D polar array is parallel to the Z axis of the current UCS. In a 3D polar array, you can defi ne a centerline axis of rotation that is not parallel to the Z axis of the current UCS. In other words, you can array an object in a UCS different from the current one. In addition, as with a 3D rectangular array, you can array the object in multiple “levels” along the Z axis. The ARRAYPOLAR command can be used to create a 3D arrangement in rows, levels, or both rows and levels. To create a 3D polar array, select the ARRAYPOLAR command. Select the object to array and press [Enter]. Then, pick the center point of the array or use the Axis of rota- tion option to select a centerline axis. The Axis of rotation option allows you to select a centerline axis that is different from the Z axis of the current UCS. Using this option requires you to pick two points to defi ne the axis. In Figure 8-13A, the leg attached to the hub must be arrayed about the center axis. The center axis is drawn as a centerline. Use the Axis of rotation option to pick the two endpoints of the axis. Once you defi ne the axis, an initial pattern of six items forms. You can use the array grips to adjust the pattern dynamically or you can use the Array Creation ribbon tab to make settings. The settings available include the number of items, angle between items, fi ll angle, number of rows and spacing between rows, and number of levels and spacing between levels. The same settings can be made using the prompts on the command line. Specify center point of array or [Base point/Axis of rotation]: A↵ Specify first point on axis of rotation: (pick one endpoint of the axis centerline) Specify second point on axis of rotation: (pick the other endpoint of the axis center- line) Select grip to edit array or [ASsociative/Base point/Items/Angle between/Fill angle/ ROWs/Levels/ROTate items/eXit] eXit: I↵ Enter number of items in array or [Expression] 6: 6↵ Select grip to edit array or [ASsociative/Base point/Items/Angle between/Fill angle/ ROWs/Levels/ROTate items/eXit] eXit: F↵ Specify the angle to fill (+=ccw, –=cw) or [EXpression] 360: ↵ Select grip to edit array or [ASsociative/Base point/Items/Angle between/Fill angle/ ROWs/Levels/ROTate items/eXit] eXit: AS↵ Create associative array [Yes/No] Yes: N↵ Select grip to edit array or [ASsociative/Base point/Items/Angle between/Fill angle/ ROWs/Levels/ROTate items/eXit] eXit: ↵ The result is shown in Figure 8-13B. In this case, a non-associative array is created. The legs are arrayed as individual objects and the resulting arrayed objects can be selected individually. As previously discussed, the Associative option setting is main- tained by AutoCAD the next time an array command is accessed. The Rows option is used to create multiple rows of arrayed objects. After selecting this option, enter the number of rows and the distance between rows. Then, set an elevation increment value to control the spacing along the Z axis between each succes- sive row. An array of seats in a theater can be created in this manner. Figure 8-14 shows an example of arraying a single seat to create multiple rows of seats. To create this array, select the ARRAYPOLAR command, select the fi rst seat, and use the following command sequence. If needed, use the Associative option to create an associative array. For this example, the default Center point option is used to set the center point of the array. Using this option is suffi cient because the Z axis of the current UCS is ARRAYPOLAR Ribbon Home Modify Polar Array Type ARRAYPOLAR