buildingSMART Data Dictionary - Connected Data for the Built Environment
The buildingSMART Data Dictionary (bSDD) is an online service that hosts classifications, properties, and materials definitions for objects in the built environment. It provides a standardized way to define and share data definitions across projects, organizations, and software platforms.
Think of bSDD as a global library of building product data definitions. Instead of every project or organization creating their own property definitions, bSDD allows you to reference standardized definitions that are understood universally, ensuring consistent data exchange throughout the building lifecycle.
Access internationally recognized classifications and property definitions from organizations worldwide.
Enable seamless data exchange between different software tools and project stakeholders.
Ensure properties are defined consistently with correct data types, units, and allowed values.
Continuously updated with new content from industry organizations and standards bodies.
A dictionary is a collection of related definitions published by an organization. Each dictionary has a unique namespace and version control.
Domains are subject areas or disciplines within a dictionary that group related classifications and properties together.
Classifications are categories or types of objects, materials, or concepts. They form hierarchies that organize building elements logically.
Properties define characteristics that can be assigned to classifications. Each property has a data type, unit, and may have allowed values.
Property sets group related properties together for assignment to classifications. They define what information should be captured.
Relations define how classifications and properties connect to each other and to external standards like IFC.
bSDD supports various data types to accurately define property values:
| Data Type | Description | Example Properties |
|---|---|---|
| String | Text values, optionally with pattern constraints | Model Number, Manufacturer Name, Description |
| Real | Decimal numbers with optional min/max bounds | Thermal Conductivity, U-Value, Flow Rate |
| Integer | Whole numbers with optional bounds | Number of Panels, Floor Level, Capacity |
| Boolean | True/false values | Is External, Fire Rated, Load Bearing |
| Time | Date and time values | Installation Date, Warranty Expiry |
| Reference | URIs linking to other resources | Product Data Sheet URL, Technical Specification |
Here's an example of how a classification with properties is represented in bSDD JSON format:
{
"uri": "https://identifier.buildingsmart.org/uri/acme/materials/1.0/class/concretewall",
"code": "ConcreteWall",
"name": "Concrete Wall",
"definition": "A wall constructed primarily of concrete",
"relatedIfcEntityNames": ["IfcWall", "IfcWallStandardCase"],
"classProperties": [
{
"name": "Concrete Strength Class",
"dataType": "String",
"allowedValues": [
{"code": "C20/25", "value": "C20/25"},
{"code": "C25/30", "value": "C25/30"},
{"code": "C30/37", "value": "C30/37"}
]
},
{
"name": "Thermal Transmittance",
"dataType": "Real",
"unit": "W/(m²·K)",
"minValue": 0
},
{
"name": "Is Load Bearing",
"dataType": "Boolean",
"isRequired": true
}
]
}
bSDD classifications map directly to IFC entities, enabling consistent property definitions that align with the IFC schema. Properties defined in bSDD can be exported as IFC property sets.
Information Delivery Specifications (IDS) can reference bSDD for property requirements. This ensures that property names, data types, and allowed values are consistent across the specification.
bSDD hosts multiple classification systems including Uniclass, OmniClass, and national standards. This allows projects to use their preferred classification while maintaining interoperability.
Manufacturers can publish product data templates (PDTs) to bSDD, defining exactly what properties their products support. This enables accurate product specification in BIM models.
The bSDD provides a REST API for programmatic access to dictionary content. This allows software applications to query and retrieve definitions dynamically.
Use bSDD property definitions to validate that BIM model elements contain required properties with correct data types and values.
Reference bSDD when writing project information requirements to ensure unambiguous property definitions across all stakeholders.
Integrate bSDD API into BIM authoring tools to provide standardized property templates and validation during model creation.
Manufacturers publish product properties to bSDD, enabling accurate specification and data exchange with design teams.
Map properties between different classification systems using bSDD relationships, enabling international project collaboration.
Ensure COBie and asset data deliverables use consistent property definitions that facility managers can understand and use.
Web interface to browse and search all dictionaries, classifications, and properties
Open bSDD SearchFor organizations to publish and manage their own dictionaries
Management PortalTechnical documentation for integrating bSDD into software applications
View API DocsOfficial documentation and standards information from buildingSMART
Learn More1. Use Existing Definitions: Before creating new properties, search bSDD for existing definitions. Reusing established definitions improves interoperability.
2. Reference by URI: Always reference bSDD content by its URI rather than copying definitions. This ensures you always have the current version.
3. Map to IFC: When defining classifications, include mappings to relevant IFC entities to enable data exchange via IFC files.
4. Use Allowed Values: Define enumerated values for properties where applicable. This prevents free-text variations and improves data quality.
5. Document Units: Always specify units of measurement for numeric properties to avoid confusion and conversion errors.
6. Version Control: When publishing dictionaries, use semantic versioning and document changes between versions.