Final answer:
In Engineering, particularly in technical drawings, almost all dimensions have tolerances; however, reference dimensions are an example of dimensions that do not require tolerances as they are provided solely for information.
Step-by-step explanation:
The question Each dimension shall have a tolerance except _____ pertains to the field of Engineering, specifically in the area of dimensioning and tolerancing in technical drawings or design. In engineering, tolerances are crucial because they define the allowable limit of variation in a physical dimension; tolerances are used to control the variation that occurs when parts are manufactured. However, there are instances where a tolerance may be deemed unnecessary. A canonical example of a dimension without a tolerance is a reference dimension, which is typically provided for information purposes only and does not dictate manufacturing or inspection requirements.