When you add constraints to a dynamic block definition, you have the option of adding editable properties that control the parameters once they are inserted in a drawing.
Geometric Constraints in Block Definitions
You can add geometric constraints to blocks the same way you would to geometry outside of the Block Editor. Geometric constraints are available both on the ribbon and on the Block Authoring palettes.
Dimensional Constraints in Block Definitions
A dimensional constraint applied within the Block Editor using the BCPARAMETER command is called a constraint parameter. While you can use both dimensional constraints and constraint parameters in a block definition, only constraint parameters will display editable custom properties for that block reference.
Constraint parameters contain parameter information that can be displayed or edited for the block reference.
The above block definition contains both a linear constraint and a horizontal constraint parameter. The horizontal constraint parameter includes a grip, while the linear constraint does not. The horizontal constraint parameter is also dynamic, while the linear constraint is not.
Show Me: Use Constraints
with Dynamic Blocks
