Complex products and systems, like an aircraft, ship, or machinery plant, involve a large number of components which are arranged under spatial constraints/relationships in design space. Current practices approximate these relationships with simplified "dimensional constraints" aiming at formulating the design problem as a system of (in)equalities to be solved automatically, e.g., by a geometric-constraint solver. This research proposes informationally-complete models for design-constraints based on an analysis of geometric and non-geometric properties of the related space volumes. Also, an Extended Product Model is proposed describing the system?s structure and components as well as related procedures and constraints to be used as a system life-cycle model.