About Dynamic Blocks

Dynamic blocks contain rules and restrictions that control the appearance and behavior of a block when it is inserted into a drawing or when it's later modified.

You can add these rules and controls to any existing block as well as using them when you create new blocks. The controls are limited to 2D operations only.

Examples of Using Dynamic Blocks

A variety of controls and behaviors are available for adding flexibility and efficiency of working with blocks. Some examples of how you could use dynamic blocks include the following:

If you notice an action that you commonly repeat when you work with blocks, you may be able to reduce the amount of trivial work and achieve substantial gains in efficiency.

The Block Editor

The Block Editor is a dedicated block authoring environment that lets you create and modify block geometry, attributes, and parameters, actions, and constraints. It includes the following components:

You can access the Block Editor by using the BEDIT command, which is available on the Home tab, Block panel on the ribbon.

Note: The third tab on the Block Authoring palette set, Parameter Sets, simply contains predefined parameters and actions that have already been combined for your convenience.

Applying Parameter Sets

With dynamic blocks you can insert a single block that can change its shape, size, or display instead of inserting one of many static block definitions. For example, instead of creating multiple interior door blocks of different sizes, you can create a single dynamic door block that can be resized to a doorway opening.

In the previous illustration, there are several visible parameters that appear as specialized grips or controls, each of which is associated with an action. The highlighted custom grip is a linear parameter that's associated with a stretch action. Paired together, these are termed a parameter set.

Tip: The order in which you specify key points when creating a parameter determines the location of a grip or control, and may have additional significance.

Here's an example of a lookup list that provides a choice between several options.

In this case, the highlighted control is a lookup parameter that's associated with a lookup action. This parameter set was designed to display a list of options to control the displayed swing angle of the door.

Applying Constraints

The parametric drawing feature set, which includesgeometric constraints, dimensional constraints, and parametric formulas, is available for use in blocks.

The ability to define constraints is not available in AutoCAD LT, but blocks that are defined in another AutoCAD-based product can be employed in AutoCAD LT without restriction.

Caution: It is possible to create constraints that conflict with the parameters and actions defined in the same block.