Create a Parametric relation
Parametric relations control the geometry or position of faces, edges, and patterns.
Relations defined between elements control the positions of the elements. For example, you can define a relation that controls the angle between two faces.
Relations on elements control the values of the element. For example, you can control the radius or diameter of a circular element.
To define a Parametric relation,
1. Click Relations and then, in the Relations Mode group, click 
Parametrics.
Parametrics.2. Click Relations and then, in the R-Sets group, click 
Active.
Active.3. Double-click the relation in the Structure Browser. Alternatively, right-click the relation set in the Structure Browser and select Set Active. New relations are automatically added to the active relation set.
4. Click Relations and then, in the Create & Modify group, click 
Relation. The Relation dialog box opens.
Relation. The Relation dialog box opens.5. Select Betw.Elems (Between Elements) for relations that have two reference elements, such as faces or edges. These relations include:
◦ Distance: Maintains a variable or measured distance between two elements.
◦ Coincident: Aligns two reference elements, such as the axes of two cylinders.
◦ Parallel: Makes two elements parallel, such as two edges.
◦ Angle: Maintains a variable or measured angle between two elements.
◦ Tangent: Makes one element tangent to another.
◦ Perpend: Makes one element perpendicular to another.
6. Select On Elem(s) (On Elements) for relations that can have one or more references of one type, such as radii, diameters, or cone angles. These relations include:
◦ Radius: Constrains the radius of one element. You must select an edge or face that has a radius for Elem(s) to define this type of relation.
◦ Diameter: Constrains the diameter of one element. Like a radius relation, you must select an edge or face that has a diameter to define this type of relation.
◦ Cone Angle: Constrains the angle of a cone. You can choose half or full cone angle.
◦ Chamfer: Constrains the value of a distance chamfer.
7. Select the element(s) for your relation in the viewport. Valid elements depend on the relation type, but in general these can be faces, edges, vertices, or patterns.
8. Select the type of relation you want to create. See Parametric relation types for illustrated examples of each type.
9. Enter a Name for the relation.
10. The menu panel will change to allow you to set the appropriate values for the relation type.
11. Some relation types allow you to change the value in the field next to Elem 1 and Elem 2. This changes how the element is referenced, such as Plane or Plane Normal for a face with an angle relation.
12. Click OK
to complete the operation.
to complete the operation.