Add a Control Variable Field node () by right-clicking a Definitions node in a Component and choosing it from the Control Variables submenu. It is also available on the Definitions ribbon toolbar, from the Optimization menu. Specify the Control Variable Field to add a control variable specific to the geometric entity level (domain, edge, boundary, or point) in question. The field can be accessed via its Name throughout the model.

Choose Lagrange, Discontinuous Lagrange, or Constant over geometric entities for the shape function type. In the latter case, you can select to group adjacent entities. Otherwise, you can select the element order of the shape functions.