The international standard defining Information Delivery Manuals (IDM) - a structured way to describe exactly what information a specific process, like clash detection, needs at each project stage. An IDM maps a real business process - say, energy analysis at concept design - to the exact IFC data it depends on, which is what a Model View Definition (MVD) then implements in software terms. Where an MVD is the technical, software-facing output, ISO 29481's IDM is the process-facing document that explains why that data is needed in the first place.