36. BIM Ontology

  Figure 1.  The BIM ontology v3.1 (Neuron Model v0.4, Updated July 28, 2016)

IMPORTANT: newer versions of the BIM Ontology are published as a BIMe Initiative resource. As of July 28, 2017, the image above and the information below may be out of date.

The BIM ontology is an informal, semi-structured, conceptual domain ontology used for knowledge acquisition and communication between people. It is intended to represent knowledge interactions (push/pull) between BIM players, their deliverables and requirements (Figure 2) as described within Papers A1 and A2 (Succar, Sher, & Aranda-Mena, 2007) (Succar, 2009) and facilitate the validation of conceptual models (Shanks, Tansley, & Weber, 2003).

The BIM ontology includes BIM-specific concepts, their relations and attributes which facilitate analysis of domain knowledge (Noy & McGuinness, 2001), enable the construction of a domain framework (Studer, Benjamins, & Fensel, 1998), and support knowledge acquisition and communication (Milton, 2007a, 2007b) (Cottam, 1999) (Studer et al., 1998). Figure 2 below illustrates how ontological objects underlie the BIM Framework. The concept map (Figure 2 – right) is a visual representation of the ontological relationship between the three concepts (BIM Fields, BIM Stages and BIM Lenses); while the visual knowledge model (Figure 2 – left) abstracts these relations into the Tri-axial Model, a simplified graphical representation to facilitate communication. As discussed in Papers A1 and A2, this combination of visual modelling, driven by explicit ontological relations, renders the BIM Framework and its many conceptual constructs more accessible for analysis, modification and extension.

Also, as depicted in the Conceptual Hierarchy post, ontological relations enable a ‘conceptual mesh’ linking different types of conceptual constructs: frameworks, models, taxonomies, classifications and specialized dictionary terms.

Figure 2. Visual Knowledge Model (left) + Concept Map (right)

Generating the BIM ontology

The BIM ontology has been generated by amending and reusing existing ontologies; a process recommended by Noy and McGuiness (2001). The reuse of an existing ontology followed Gruber’s criteria for shared ontologies: clarity, coherence, extensibility, minimal encoding bias and minimum ontological commitment (Gruber, 1995). Based on these criteria, the BIM ontology was first derived from the General Technological Ontology (Milton, 2007a) (Milton, 2007b) and the General Process Ontology (Cottam, 1999). While earlier iterations of the BIM ontology followed source definitions, newer iterations are more closely matched with the conceptual and practical requirements of the BIM domain.

Knowledge Objects

The BIM ontology comprises of four high-level knowledge objects: concepts, attributes, relations and knowledge Sets (Table 1):

	Knowledge Objects	Description	Examples
I	Concepts (Table 2)	A mental construct	Component; Document; Role
II	Attributes (Table 3)	Values and qualifiers associated with Concepts	Cost; Count; Description
III	Relations (Table 4)	Connections between Concepts; the effect of one Concept on another	Approves; Detects; Supplies
IV	Knowledge Sets (Table 5)	A purposeful compilation of Concepts, their Attributes and Relations	Knowledge Foundations; Knowledge Blocks; Knowledge Views

Table 1. BIM Ontology Knowledge Objects (v3.0, last updated August 16, 2015)

 I. Concepts

Ability	Activity	Certificate	Component	Conception	Conceptual Construct	Constraint
Data Source	Data Use	Deliverable	Designation	Document	Document Use	Effect
Equipment	Event	Example	Facility	Format	Function	Hardware
Incentive	Information Use	Knowledge Domain	Lesson	Machine	Measurement	Medium
Message	Method	Milestone	Model	Model Use	Place	Player
Product	Proof	Recommendation	Representation	Requirement	Responsibility	Result
Role	Rule	Scenario	Software Application	Space	Standard	System
System Unit	Target	Test	Tool	Trigger

Table 2. Concepts (51 Concepts in v3.10, last updated July 28, 2016)

II. Attributes

Name	Description	Name	Description
Availability	An integer or string indicating the basic existence or availability of a concept	Location	The coordinates of an object within a physical space
Cost	A monetary value expressed in whole numbers, fractions or decimals	Market	A defined economical boundary
Count	An expression of elemental numbers using integers	Order	An arrangement whether chronological or spatial – not preferential or developmental (refer to Grade)
Description	An explanation expressed using words, phrases and sentences	Proposition	A mutually exclusive distinction between clear choices
Grade	A variables denoting preference or developmental achievement expressed in integers, percentages or text	State	A description of condition whether temporary or permanent
Link	A hypertext connection	Time	An expression of chronology expressed in minutes, second, days, etc…
Language	The language used to define a concept or a relation	Type	A differentiation of genus

Table 3. Attributes (14 Attributes in v3.0, last updated August 16, 2015)

III. Relations

Below is a list of all standard relationship labels (158 as of Aug, 2015) connecting different Concepts:

Table 4. Relations (158 Relations in v3.0, last updated August 16, 2015)