1. A computer-implemented method for providing an element associated with a model-based design represented by a graphical model to identify a precondition for verification of the model-based design, the method comprising: providing, in a modeling environment, a graphical model representing an executable model-based design; identifying a portion of the graphical model to associate with a precondition for verification of the model-based design, the precondition comprising a constraint to apply in verification of the model-based design, the precondition allowing the verification to be performed only when a variable in the model-based design satisfies the constraint; providing an element in the graphical model to represent the precondition associated with the identified portion of the graphical model, wherein: the element includes information indicating the constraint to apply in a verification of the model-based design, and during simulation of the model-based design of the graphical model including the element representing the precondition, the element representing the precondition is automatically ignored; and displaying the element in the graphical model on a display device.