Model-Based Definition > Geometric Dimensioning and Tolerancing Advisor > Advisor Message Help > Value Messages > The Form Tolerance Must Be Smaller Than the Specified Size Tolerance
  
The Form Tolerance Must Be Smaller Than the Specified Size Tolerance
The form of a feature of size is constrained by its size dimension, as specified by Rule #1. Thus, a size dimension applied to a feature of size implies an equal constraint on its form. Similarly, a profile tolerance applied to constrain the size of a feature implies equal constraint on its form. When you explicitly specify a form control on the feature of size, the tolerance value for that control should be less than the specified size dimension tolerance range or the profile tolerance.
Note that this message is shown whenever there is a form tolerance associated with a size dimension without an explicitly specified tolerance (i.e., Tolerance Type='Nominal'). Whenever refining the form of a feature of size with a tolerance of form, it is good practice to explicitly specify the size tolerance.
To eliminate this problem, you could change the form tolerance to be less than the size dimension tolerance range or profile tolerance. Conversely, you could change the size dimension tolerance range or profile tolerance to be greater than the form tolerance.