8. A data processing system comprising: a processor; and an accessible memory, the data processing system particularly configured to: receive a Computer Aided Design (CAD) model including a plurality of entities; receive a user input including a selection of at least one entity and a movement of the selected entity; apply any basic condition behaviors that correspond to the user input; apply any optional condition behaviors that correspond to the user input; build a variational system to be solved based on the user input, any applied basic condition behaviors, and any optional condition behaviors; perform a variational solve on the variational system to produce an edited CAD model; and store the edited CAD model.
8. A data processing system comprising: a processor; and an accessible memory, the data processing system particularly configured to: receive a Computer Aided Design (CAD) model including a plurality of entities; receive a user input including a selection of at least one entity and a movement of the selected entity; apply any basic condition behaviors that correspond to the user input; apply any optional condition behaviors that correspond to the user input; build a variational system to be solved based on the user input, any applied basic condition behaviors, and any optional condition behaviors; perform a variational solve on the variational system to produce an edited CAD model; and store the edited CAD model. 9. The data processing system of claim 8 , wherein the data processing system applies at least one basic condition behavior that is a single edge vertex condition, a two-edge vertex condition, a touching-vertex condition, a three-or-more-edge-vertex condition, a connected-arc condition, or a general-curve condition.