| | 4.1 General object property requirements
This sub-section of the standard defines the general rules for properties associated with BIM objects including the requirements for using non-conforming hard-coded properties within BIM authoring applications. |
| 4.1.1 | Provision of properties
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| | Properties can either be embedded within the object or linked via a unique link to an external database. |
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| 4.1.2 | Extent of properties
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| | Only properties that are deemed necessary to adequately define the object for its intended BIM use(s), and to provide for object interoperability between BIM applications, shall be provided. |
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| 4.1.3 | Duplication of properties
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| | An object shall not include duplicate occurrences of a property.
Where an identical property, either in name or in description/value requirement, exists in multiple sources (for example, IFC and COBie), only include a single occurrence of that property.
IFC properties shall take precedence over properties from other sources. |
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| 4.1.4 | Hard-coded properties
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| | Hard-coded properties within the BIM authoring system shall be used.
Where necessary, hard-coded properties shall be mapped to their corresponding IFC properties at export, see clause 7.2.
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| 4.1.5 | Proprietary and generic object properties
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| | Proprietary objects shall, as a minimum, include the same properties as those provided for a generic object of the same object type and subtype.
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| 4.1.6 | Property values
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| | Property values shall be completed where known.
Proprietary objects shall have all Type property values completed, see clause 4.2.1.
Property values can be completed with: - A fixed value, where only one value is available or a decision has been made on which value is required, for example, 6000.
- A value range, where a bounded range of values are available and a decision has not been made on which value is required. The lower and upper bound of the available range shall be separated by a hyphen, for example, 100 – 600
- An enumerated value, where a number of values are available from a defined list of enumerators and a decision has not been made on which value is required. Each available enumerator shall be separated by a comma, for example, X, Y, Z.
- A formula, if the value is reliant on the value of another property.
Property values shall not: - Finish with a full stop( ).
- Include units, unless specifically required to do so in the property description.
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| 4.1.7 | Property units
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| | Units shall be metric unless specified otherwise by local requirements.
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| 4.1.8 | Property data type
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| | Properties shall have their data type defined using ANSI SQL data types, selected from the following list: - Character (Text, String) – for fields requiring alpha numeric or text values.
- Integer – for fields requiring whole numbers.
- Decimal (Number, Currency) – for fields requiring decimal numbers.
- Date – for fields requiring a date in the format year-month-day (YYYY-MM-DD).
- Boolean (Yes/No, True/False) – for fields requiring a choice from two options.
- Hyperlink (URL) – a character fi eld where values are links represented as www.website.domain/path
If a data type listed above is not available, or a more specific hard-coded data type is available, within the BIM authoring system being used, use the most appropriate hard-coded data type. For example, if there is no Date data type, use a Character type and enter the date in the correct format. |
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| 4.1.9 | Assembly properties
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| | Assemblies shall not have properties assigned to the assembly itself.
All properties shall be assigned to the objects contained within the assembly. |