IDS reference

Example below. IDS (Information Delivery Specification — buildingSMART standard, approved 1 June 2024) is the machine-readable contract for what data a BIM model must carry. This viewer covers concepts, the six facet types, cardinality rules, the lifecycle workflow, full XML examples, and six free / open-source IDS tools you can use today. Press / to focus the search box.

What it is

A specification is a single, self-contained rule. It has two halves: an applicability block (which IFC elements does this rule apply to?) and a requirements block (what data must those elements carry?). One IDS file holds many specifications — group them by phase (Design / Construction / FM), by discipline (Arch / Struct / MEP), or by purpose (Cost / Carbon / Maintenance) so the failure report stays readable.

XML shape

<specification name="Wall fire rating" ifcVersion="IFC4">
  <applicability>
    <entity><name><simpleValue>IfcWall</simpleValue></name></entity>
    <property dataType="IfcBoolean">
      <propertySet><simpleValue>Pset_WallCommon</simpleValue></propertySet>
      <baseName><simpleValue>IsExternal</simpleValue></baseName>
      <value><simpleValue>true</simpleValue></value>
    </property>
  </applicability>
  <requirements>
    <property dataType="IfcLabel">
      <propertySet><simpleValue>Pset_WallCommon</simpleValue></propertySet>
      <baseName><simpleValue>FireRating</simpleValue></baseName>
      <value><restriction base="xs:string">
        <pattern value="^[0-9]+/[0-9]+/[0-9]+$"/>
      </restriction></value>
    </property>
  </requirements>
</specification>

The six facet types

Free / open-source IDS tools

Why this matters for estimators & BIM leads

Without IDS, the BOQ extract from a model fails on Friday afternoon because the FireRating property the cost plan depends on was never populated. With IDS, the modeller's authoring tool fails the validation at every weekly issue and they fix it. The whole point is to surface data gaps early, in the modeller's hands, not late in yours.

Coverage in this viewer