What is IDS (Information Delivery Specification)?

An Information Delivery Specification (IDS) is an XML-based file format developed by buildingSMART that lets a client, employer or project team express their BIM information requirements in a form that a computer can validate automatically.

Traditionally, information requirements were written in documents (EIRs, BIM Execution Plans) that described what should be in the model in prose — making compliance checking a manual, judgement-dependent process. IDS replaces that with structured rules.

An IDS file specifies:

• Which elements the rule applies to (by IFC class, type or property value)
• What property must be present (e.g. fire rating, load-bearing status, manufacturer)
• What value it must have, or what data type it must be
• At which stage the requirement applies (concept design, detailed design, construction, handover)

For example, an IDS rule might say: "all IfcWall elements with a fire-compartment function must have a FireRating property with a value from the set {EI30, EI60, EI90, EI120}."

When an IDS is validated against an IFC model, the output is a structured pass/fail report showing exactly which elements fail which rules — eliminating guesswork and enabling continuous compliance checking as the model develops.

Bildstak reads IDS files and validates them against the connected IFC model automatically, surfacing gaps as AI-queryable data. This means information quality can be monitored throughout the design and construction phases, not just at gateway reviews.