806 AutoCAD and Its Applications—Basics Copyright Goodheart-Willcox Co., Inc. Chain Actions Ch a in Action s A chain action limits the number of edits that you have to perform by allowing one action to trigger other actions. For example, Figure 26-30 shows using a chain action to stretch the block of a table and chairs, and array the chairs along the table at the same time. You can use a chain action with point, linear, polar, XY, and rotation parameters. Creating a Chain Action To create a chain action, select the Chain option available at the fi rst prompt after you access a parameter option to display the Evaluate associated actions when parameter is edited by another action? [Yes/No]: prompt. The default No option does not create a chain action. Select the Yes option to create a chain action. Figure 26-31 shows the default arrangement of the table and chairs block example. For this example, access the Linear parameter option and use the Label option to change the label name to CHAIR ARRAY. Next, select the Chain option and select Yes. To complete the parameter, select the start point and endpoint shown in Figure 26-31A, and assign a single grip to the endpoint. Then assign an array action to the parameter, selecting only the upper-right and lower-right chairs as the objects to array. At the Enter the distance between columns: prompt, use object snaps to snap to the endpoint of one of the chairs and then snap to the equivalent endpoint on the chair next to the fi rst chair. Add another single-grip linear parameter, labeled TABLE STRETCH, as shown in Figure 26-31B. Assign a stretch action to the parameter associated with the TABLE STRETCH parameter grip. Use a crossing window around the right end of the table and the CHAIR ARRAY parameter grip. See Figure 26-31C. Select the table, the chair at the right end of the table, and the CHAIR ARRAY parameter as the objects to stretch. Test and save the block, and exit the Block Editor. The dynamic block is now ready to use. chain action: An action that triggers another action when you modify a parameter. Figure 26-30. A—A block of a table with six chairs. B—Use a chain action with a linear parameter to array the chairs automatically when you stretch the table. A B