Masterspec

4.0 Object Properties & Property Grouping

This section of the standard defines the properties that should be assigned to a BIM object. It also discusses the grouping of properties and the assignment of properties to object types or object instances.

4.1 General object property requirements

  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
  Properties can either be embedded within the object or linked via a unique link to an external database.
   
 4.1.2 Extent of properties
  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.
   
 4.1.3 Duplication of properties
  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.
   
 4.1.4 Hard-coded properties
  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.
   
 4.1.5 Proprietary and generic object properties
  Proprietary objects shall, as a minimum, include the same properties as those provided for a generic object of the same object type and subtype.
   
 4.1.6 Property values
 

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.
   
 4.1.7 Property units
  Units shall be metric unless specified otherwise by local requirements.
   
 4.1.8 Property data type
 

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.

   
 4.1.9 Assembly properties 
 

Assemblies shall not have properties assigned to the assembly itself.
All properties shall be assigned to the objects contained within the assembly
.

 

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