Geometrical defects of a manufactured feature are limited by form, size and location tolerances. The standardized semantics of those tolerances, i.e. their interpretation on the manufactured feature, presents a lot of drawbacks. We propose new semantics, based on the fitting of a unique theoretical feature on the manufactured feature. The fitting criterion we propose, named minimum volume criterion, leads to the actual mating envelope of the manufactured feature. For some functional requirements the tolerancing shown to become simpler and more functional.