Last time, we covered the basics of dynamic block creation. This time, we’ll take a more in-depth look at some of the options available when you add a parameter.
If you want one action to cause more than one change in a block, you can chain parameters so that when you activate one parameter’s actions, the actions of the secondary parameter also occur. The primary parameter must have an action whose selection set includes the secondary parameter along with any objects it will act on. The secondary parameter’s Chain property must also be set to Yes.
Value sets allow you to constrain the available values for your block’s size. These take the form of lists of values or allowable increments, with minimum and maximum values. For example, your block may come in lengths of 24”, 36”, and 48”. Or perhaps the length can vary from 10 cm to 50 cm in increments of 5 cm.
You can specify a value set when you create a parameter. When you select this option, you are first asks to choose either the increment or the list method.
Caption: The first step in creating a value set is specifying whether you want a list or an increment. Prompt here is for a Rotation parameter.
AutoCAD then prompts for the values. For a list, you are asked to enter a list of values (the type of value will vary depending on the parameter). Values are separated by commas.
Caption: Rotation parameter asks you to enter list of angle values.
For an increment, AutoCAD first prompts for the increment, then for a starting and ending value.
Caption: Linear parameter asks you to enter an increment for distance.
You can also select an existing parameter and use the Properties palette to create the value set (and change other dynamic block properties, for that matter).
Caption: Use the Properties Palette to add value sets to existing parameters in dynamic blocks.
This option creates a base point parameter that determines the base point for the block.
You can change the name of a parameter, but you may find it more useful to keep the parameter’s original name so you know exactly what parameter a particular block uses. This option can come in handy, however, if you have two instances of the same parameter. In that case, you may want to make each one more descriptive—for example, Move Nut and Move Bolt.