With dynamic blocks you can insert one block that can change shape, size, or configuration instead of inserting one of many static block definitions. For example, instead of creating multiple interior door blocks of different sizes, you can create one resizable door block.

You author dynamic blocks with either constraint parameters or action parameters.

Note:
Using both constraint parameters and action parameters in the same block definition is not recommended.

Checkout my online presentation about dynamic block tutorial embeded on this post. Thanks for reading.