Extended modules > Relations > Parametric relations > About relations for patterns
  
About relations for patterns
You can create relations to control the parameters of a pattern. For example, you could define a relation set that controls the number of objects in a pattern based on the part's size. If one or more dimensions of the part change, then the number of objects in the pattern will change.
For positioning a pattern you can constrain either a geometric reference of the pattern or the patterns origin or center relative to another element. If you position the pattern by constraining the origin or center, you can constrain other values of the pattern such as directions, distance, number, angle, or radius.
The primary difference when creating these types of relations is the focus. In the Relation dialog box, select Betw.Elems (Between Elements) to constrain a geometric reference of the pattern, its origin, or its direction; select On Elem(s) to constrain the values of a pattern.
Constrain a geometric reference of the pattern
You can constrain a pattern using a geometric reference of the pattern relative to another geometric element or another pattern.
For example, we want to constrain the pattern of square pockets so it is parallel with the front face of the part.
When we create the relation, we first select the pattern and a face, edge, or vertex on the pattern. We selected the green face.
We then select any face, edge, or vertex. We selected the yellow face.
The pattern’s position will be determined by the relation between these two faces.
We created a parallel relation. When we update the relation set, the pattern moves so the Reference is parallel with the yellow face.
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The yellow face has been constrained with a fixed relation. This assures us that the pattern will move rather than the yellow face.
Follow these instructions to create this type of relation.
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Creo Elements/Direct Modeling cannot constrain a geometric reference of parts of a pattern.
Constrain the origin and values of the pattern
You can also define the pattern’s position by constraining its origin.
First we set up two relations to constrain the origin with a certain distance to the planar side faces.
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We make sure that the pattern moves, rather than the side faces, by creating a fixed relation on the side faces.
Follow these instructions to create this type of relation.
Because we only constrained the origin to position the pattern, we can also constrain other pattern values.
We increase the length of the part using the distance relation for the length defined between the two faces shown in yellow. Another square pocket is added because we increased the length far enough.
This is our modified part after we update relations.
Follow these instructions to create this type of relation.