Dictionary
BIM & VDC Knowledge Dictionary
Vendor-neutral definitions of BIM, VDC, ISO 19650, openBIM and digital construction terms, each with a quick definition, a plain-language explanation, a practical example and its sources.
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Acronyms decoded
Look up OIR, AIR, PIR, EIR, MIDP, TIDP, IDS, BCF and more, including acronyms with more than one meaning.
Core BIM and information management terms
Building information modelling (BIM)
The use of a shared digital representation of a built asset — its geometry, properties and related documents — to support design, construction and operation decisions with reliable information.
Common data environment (CDE)
The agreed single source of information for a project or asset, used to collect, manage and share each information container through a controlled workflow of states, statuses and revisions.
Exchange information requirements (EIR)
The information requirements that an appointing party (or lead appointed party) sets for a specific appointment: what information is to be delivered, to what standard, when, and how it will be accepted.
Level of information need
A framework for specifying the extent and granularity of information required for a purpose — covering geometry, alphanumeric data and documentation — so that no more and no less is delivered than is needed.
Industry Foundation Classes (IFC)
An open, vendor-neutral data schema for describing buildings and infrastructure — their elements, properties and relationships — published by buildingSMART and standardised as ISO 16739-1.
Master information delivery plan (MIDP)
The delivery team's combined schedule of all information to be delivered for an appointment, compiled by the lead appointed party from the task information delivery plans.
Construction, contracts and project management
Request for information (RFI)
A formal written question from the contractor to the design consultant asking for clarification of the contract documents — typically about design intent, an apparent omission or a conflict.
Change order
A written amendment to the construction contract, signed by the owner and contractor, recording an agreed change in the work together with any adjustment to the contract price and time.
Holdback
A percentage of each payment that the payer must retain under lien legislation — 10% in Ontario — until the period for registering construction liens has expired, as security for subcontractors and suppliers.
Design-build (DB)
A delivery method in which one entity, the design-builder, contracts with the owner to provide both the design and the construction under a single contract.
Critical path method (CPM)
A scheduling technique that models a project as a network of dependent activities and identifies the longest path through it — the critical path — which sets the shortest possible project duration.
Ready-for-Takeover
A contractual milestone introduced in CCDC 2 (2020) that marks when the owner can take over the work, reached once specified conditions — including certified substantial performance and occupancy permission — are met and verified by the consultant.