When you place a component relative to its neighbors (components or assembly features), its position is updated as its neighbors move or change, provided the assembly constraints are not violated. This is called parametric assembly.

Components can be placed in a number of ways:

Component placement is based on placement definition sets. These sets determine how and where the component relates to the assembly. The sets are either user-defined or predefined. A user-defined constraint set has 0 or more constraints (a packaged component may have no constraints). Predefined constraint sets have a predefined number of constraints.

Placement of a component in an assembly is determined by the constraints in all sets defined. A single set of constraints can define placement of a component. If constraints from one set conflict with constraints from another set, the placement status becomes invalid. The constraints must be redefined, disabled, or removed until placement status becomes valid.

Constraints can be added or deleted at will in a user-defined constraint set, there are no predefined constraints. Each type of predefined constraint set (also called a connection) has a predefined number of constraints.

A constraint set can be disabled and another constraint set created to create a variety of placement options.

Constraint sets are displayed in the Placement folder of the Model Tree. Display hierarchy follows the order in which they were defined. Constraint icons are the same as those in the Component Placement tab. If only one set is defined, only constraints appear. The Model Tree Placement Folders filter must be activated to view the Placement folder.

By default, the placement references of newly created components are not backed up. Change this behavior by setting the placement_references_backup_default_setting configuration option to yes.