Assembly Design > Using Assembly > Placing Components > Assembling Components to a Pattern > Assembling Components to a Reference Pattern
  
Assembling Components to a Reference Pattern
A component assembled to references of a pattern in an assembly can be patterned by referencing this pattern. The Reference option is automatically selected when the Pattern tab opens. For example, to place bolts into a pattern of holes, you must specify the assembly constraints only once, between the bolt and the first, or leader, hole.
When assembling components to a reference pattern, keep in mind the following rules:
You can select references from two patterns in a set of placement constraints, but the system uses only the first pattern for subsequent components.
If you assemble a component to an assembly feature that is the leader of the pattern, you cannot reference this pattern.
Components placed in the assembly and used as a reference pattern can be used to assemble another pattern of components. For example, if you have bolts assembled in a pattern of holes using the Reference option, you can use Reference again to assemble a pattern of nuts directly to the bolts.
If the existing pattern is part of a group and that group is patterned, the new pattern can reference the feature pattern, the group pattern, or both patterns.