COBie 2.4 · Supporting guide
Attribute
Adds agreed properties that do not belong in the standard columns of another worksheet.
How should project-specific data be added without changing the standard sheets?
Extend COBie without changing its core columns
Attribute is the standard worksheet for properties that do not belong in the fixed columns of another COBie sheet. In the COBie spreadsheet schema, Attribute.Name, SheetName, and RowName form the compound identity that says what the property is and exactly which COBie record it extends. Category separately describes the information context.
This row-based approach is preferable to adding project-specific columns to Type, Component, Space, or another core worksheet. A receiving system can process the standard schema first and then import Attributes as extensible properties without having to discover a different spreadsheet layout for every project.
Define meaning, value, unit, and constraints
Value carries the property value and Unit explains its measurement where applicable. AllowedValues can constrain a property to an agreed list, while Description can define the intended meaning or source. Category can distinguish requirement, submitted, approved, and as-built contexts so teams do not mistake a target value for a verified delivered value.
Attribute names should be governed like any other data dictionary. Variants such as 'Flow Rate', 'Airflow', and 'Design Air Flow' may describe the same concept but produce separate properties if left uncoordinated. The project should agree spelling, units, categories, and allowable values before large volumes of rows are generated.
Map Revit parameters into governed Attributes
Revit instance and type parameters are common Attribute sources, but internal parameter names and units do not automatically provide a usable COBie definition. Shared parameters, family parameters, calculated values, and duplicate display names need clear source priority and a target Attribute name that the receiver understands.
BIMRelay exposes sheet and column sources using the model's actual Revit parameter names, keeps model-derived values tied to source identity, and preserves project-authored Attributes through regeneration. It can also validate every SheetName and RowName reference so an Attribute does not remain attached to a deleted or renamed workbook record.
Key relationships
Can extend many worksheet records
Uses worksheet and row references
Practical quality checks
- Do not add custom columns to core sheets
- Use consistent names and units
- Validate the referenced row
Attribute worksheet FAQ
- What is the COBie Attribute worksheet?
- Attribute stores a named project-specific property against a row in another COBie worksheet, together with its value, unit, category, description, and optional allowed values.
- Should custom COBie data be added as new columns?
- Generally no. Project-specific properties should be represented as Attribute rows so the standard core worksheet columns remain interoperable.
- Can COBie Attributes come from Revit parameters?
- Yes, when a controlled mapping defines the source parameter, target name, unit, category, and applicable COBie records. The mapping should not rely only on similar-looking labels.
- How does BIMRelay manage Attribute mappings?
- BIMRelay lets teams configure model-backed sources using the Revit parameter vocabulary found in the extracted model and validates the resulting Attribute target references.
This is an independent practical summary, not a reproduction of the COBie specification. Refer to the official standard for normative definitions and field requirements.
Reviewed against the official NIBS COBie 2.4 publication and Annex A worksheet schemas.
Where the official documents, contract-issued workbook, and project validator differ, follow the contract requirements and accepted validation process.
Open the official COBie 2.4 publicationOpen the official COBie 2.4 Annex A worksheet schemas