Extended modules > Relations > Parametric relations > Create a relation for a pattern
  
Create a relation for a pattern
Three relation types affect only patterns: distance, number, and angle. A distance relation controls the distance between features in the pattern. A number relation for a pattern controls the number of features in the pattern. An angle relation controls the angles between features in a pattern. See About relations for patterns.
These relations are special for patterns. You can also define Create a Parametric relation for a pattern.
To define a pattern relation,
1. Click Relations and then, in the Relations Mode group, click Parametrics.
2. Click Relations and then, in the Create & Modify group, click Relation. The Relation dialog box opens.
3. Select On Elem(s).
4. Select the pattern in the Structure Browser for Elem(s).
5. Select a Parameter to constrain and set its values. You must create a separate relation for each parameter you want to control with relations.
6. Enter a value for Distance, Number, or Angle, or click Exp and enter a Using mathematical expressions.
7. Select Keep Elm 1 and click Next if you want to create another relation with the same selection for Elem 1.
8. Click Next to create another relation without closing the dialog.
9. Click OK to complete the operation.
Limitations
If a pattern modification fails, relations referencing the pattern remain unsolved and you will receive an error message in the display box.
Distances are always positive, and values cannot be less than 1. If an expression evaluates to a negative distance or value, it is automatically set to 0. If an expression evaluates to less than 1 but greater than 0, it will be set to 1.