Use sketch blocks in your layout to represent components. Once a sketch block is created, you can easily add instances of the block to your layout. For components used in multiple locations, it provides a quick, associative method for adding them to the design. Any changes to the block definition are propagated to all block instances.
A powerful use of sketch blocks is the creation of flexible, nested blocks. This type of block allows you to simulate assembly and subassembly kinematics in your layout. You can evaluate your design and change the design before you make components. You can also evaluate the impact of any changes in your design. If changes to the sketch block definition are made, the block instances are updated.