ObjectOriented Building Models

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Object-Oriented Building Models

• Kaj A. Jørgensen
• Aalborg University, Department of Production

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Aalborg

• New
• Concert
• Hall

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Computerbaserede bygningsmodeller
Jørn Utzon skaber sin kunstneriske form 1957
Jørn Utzon skræller en appelsin
Jørn Utzon får geometrien af formen bestemt
Forudsætningen for et rationelt byggeri
Samtidig begynder det danske montagebyggeri
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Computeren som regnemaskine
Computeren muliggør præcis geometri af frie former
Det er 3D - men ren geometri
Målsætning og produktionsgrundlag
Forudsætningen for et præcist byggeri
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Den parametriske komponent
Komponenten er designet og programmeret hos
producenten
Arkitekten tager den ind i sit projekt og
tilpasser den
Arkitektens elektroniske bygningsmodel består
således af objekter så den kan gøres til
genstand for simulering af forskellig art
Den tilpassede komponent danner grundlag for
producentens fremstilling, styklister, tilbud mv.
Det er 3D med Intelligens
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Bygningsmodel Sorthøjparken Aalborg
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Fundamentals of Building models

• Analytic models versus synthetic models
• The object concept
• Attributes

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Modelling two approaches

• Analytic modelling
• modelling by abstraction

• Synthetic modelling
• realisation of artefacts

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Modelling two kinds of models

• Analytic models

• Synthetic models

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Synthetic Modelling is the Foundation
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Synthetic Building Models

• Modelling is performed as a synthetic model
• The physical building is constructed from a
  synthetic model
• Various representations are necessary
• on different levels of abstraction
• on different levels of detail
• Several domains must be included in the
  representation
• building
• actors and resources
• activities
• etc.
• The building should be modelled for the complete
  life cycle

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The Object Concept

• In the real world
• objects are living and communicating organisms
• objects have properties
• factual properties
• operational properties - behaviour
• In data models
• software objects are representations of real
  world objects
• software objects are described by attributes
• analytic view classes of objects - members of
  classes
• synthetic view types of objects - objects are
  instances of types
• two design levels the type level and the object
  level
• abstraction mechanisms classification and
  composition can be applied

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Building Modelling

• Building CAD tools generally contain
• Models of physical objects and products is the
  foundation
• Walls, columns, beams, openings, etc.
• Libraries of objects and products
• Windows, doors, furniture, lamps, etc.
• An analytic view of the building is often used
• A number of problems are related to this, e.g.
• What are rooms?
• Is a complete front wall one or many objects?
• How can functional requirements be described?
• A number of other tools must be used also - model
  exchange

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Building Objects e.g. wall-element

• Models are built from objects
• Object properties are specified
• Geometry
• Materials
• Prices

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Models

• Generic model component
• Attributes and structures of sub-components
• Relationships
• Modelling matrix

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Information Modelling Generic Model Component

• Model component
• Living organism - communicating
• Content
• attributes
• factual - state
• operational - behaviour
• structures of sub-components
• references
• collections
• Encapsulation - attributes can be
• visible for other systems
• hidden from other system

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Data Modelling Fundamentals, cont.

• References
• A reference contains the address value of another
  object
• Symbol in type diagrams arrow
• A reference can be used to represent an oriented
  relationship between two objects
• examples window ? wall floor ?
  roombuilding ? building complex

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Data Modelling Fundamentals, cont.

• Collections
• Oriented relationship between two object types
  examples wall ---gtgt window, room ---gtgt wall
• Symbol in type diagrams double-headed arrow
• Anchor type and body type
• Identified by a special attribute in the anchor
  type
• One-to-many relationships
• Internal organisation - information structure
• static structure - array
• dynamic/linked structures standard structures
  lists, trees, networks

?
?
CDset
CDdata
Object types
Objects
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Dynamic Data Structures - Linked Representations

• Characteristics - Efficiency
• Insert and remove operations
• Retrieval operations most efficient search
  trees
• Standard structures
• List structures
• Single-linked
• Double-linked
• Tree structures
• Binary trees
• Multi-way trees
• Networks

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Model Detailing Attributes X Structure
Identification of attributes
Identificationof structure
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Instantiation from Model Component Types

• Component types
• Primary content of information models
• Identification - definition - specification
• Attributes - name, data type, constraints
• Relationship types
• reference types
• collection types
• can be defined by special attributes
• Components
• Generated from types
• Indefinite number of instances

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Abstraction Mechanisms

• Composition Aggregation versus Separation
• Classification Generalisation versus
  Specialisation

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Building Models and Abstraction Mechanisms

• Application of two abstraction mechanisms
• Classification
• Composition
• Composition
• Aggregation/separation, consists-of / part-of
  relationships
• Ex building ground floor wall paint
• Classification
• Generalisation/specialisation, is-a relationships
• Ex Buildings classified by materials
• wooden, steel, concrete, brick, etc.

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Composition System and Environment/Surrounding
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Composition Hierarchy
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Composition of buildings

• Hierarchy Example 1
• Building
• B1
• B2
• Building section
• BS1
• BS2
• Storey
• S1
• S2
• Room
• R1
• R2
• Furniture
• ...

Building
Rooms
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Composition of buildings

• Hierarchy Example 2
• ...
• Storey
• S1
• S2
• Room
• R1
• ...
• Building component
• BC1
• BC2
• Building component
• BC21
• ...

Rooms
Building elements
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Composition of buildings

• Hierarchy Example 3
• Storey
• S1
• S2
• Building component
• BC1
• BC2
• Building component
• BC21
• BC22
• Building component
• BC221
• BC222
• ...

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Building Models and Classification

• Classification of building objects
• Selection of attributes
• Possibly values/value ranges
• Taxonomy structure, hierarchy
• types/classes of objects
• Taxonomies of object types
• Built for easy selection of objects
• Dynamic creation of taxonomies
• Criteria provided by the user

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Computer-Based Models Based On Information Models
Composition
Classification
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Classification Example Taxonomy of Components
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Composition Example Taxonomy and References
Component
Door
Hinge
Normal
Painted
Single
Double
Doorstep
Type 2
Type 1
Type 3
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Composition Example Taxonomy and Collections
Component
Door
Hinge
Normal
Painted
Single
Double
Doorstep
Type 2
Type 1
Type 3
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Building Model Design Tools Libraries of Object
Types

• Ex furniture

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Representation of Models

• Fundamental system concepts
• Abstraction mechanisms
• Composition
• Classification
• Object-orientation
• Objects with properties and behaviour
• OO modelling is modelling in multiple dimensions
• Taxonomies of models are the foundation
• Objects and relationships are selected from
  taxonomies
• Objects have pre-defined sets of properties
• Model components are interrelated software
  objects
• Building models representing e.g. walls, floors,
  roofs, windows, doors

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Representation on Multiple Abstraction Levels is
Necessary

• Proposed logical abstraction levels above the
  physical level
• Purpose, the overall purpose or need for the
  building
• Use, the user processes
• Function, the functionalities/features of the
  building
• Form, the architectural characteristics
• Structure, the structural characteristics
• Components, the building contents
• Performance, the building performance
• Dual view
• Requirements
• Fulfilment

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Building Model LifecycleModel Data Exchange

• STEP and IFC
• The IFC Data Model
• IFC and Applications
• IFC Model Servers

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Bygningsmodellers anvendelse i den totale
livscyklus
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Bygningsmodellens anvendelse i bygningens
livscyklus

• Bygningsmodellering
• Anvendelse af modeller af bygningsobjekter
• Udvikling/anvendelse af produktmodeller
• Analyser og simuleringer
• Visualiseringer,
• Analyser af statiske, termiske og akustiske
  forhold
• Produktionsstyring
• Indkøb, leverandørstyring, logistik
• Økonomistyring, kalkulationer, budgetter,
  omkostninger, mv.
• Drift og vedligeholdelse
• Håndtering af ændringer

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Use of Standards - STEP and IFC

• ISO STEP (ISO 10303)
• STandard for Exchange of Product model data
• International Alliance for Interoperability (IAI)
• Industrial Foundation Classes (IFC)
• partly based on STEP
• oriented towards the building sector
• Standardised technical platform
• Implementation and use of STEP and IFC
• A very important development in the SW industry
  has been carried out
• Building models can be exchanged based on IFC
• Focus on cooperation, integration, and
  interoperability

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Industrial Foundation Classes (IFC)

• Standardised format for product data exchange
• Object-oriented data model for representation of
  building models
• Generalised representation large variety of
  models
• Building components and structures
• Actors and resources
• Activities
• Data model elements developed during iterative
  process
• IFC is oriented towards representation of
  physical entities
• The data model is developed from the analytical
  approach
• Models on higher abstraction levels are not
  represented
• Parameterisation and versioning are not
  represented

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Industrial Foundation Classes
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IFC Relatively Physical and Analytic Oriented
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IFC From a Metadata Point of View

• IFC does not claim to be a metamodel proposal
• IFC is a conceptual model
• Express language, graphical and verbal
• IFC integrates separate models of building
  components, operations, activities, actors, etc.
• Classification has resulted in a hierarchy of
  concepts
• Entity types
• Relationship types
• The IFC model has a substantial amount of
  semantic data
• The validity of the model is well proven

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Product Models and The Building Model
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Building Model and Separate Construction Model
Buildingobjects
Building Model for the building life cycle
Operations,equipment, etc.
Construction Model
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Building Model and Construction Models

• Project organisation
• Project composition network of activities and
  operations
• The building is the basis additional
  decomposition necessary
• Additional objects related to production, not
  incl. in the building
• Production equipment
• Each operation
• Input set of objects
• Output one or more objects
• Attributes use of resources, constraints, etc.
• The building model must be updated
• Material consumption, elapsed time, cost, etc.

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Building Construction Tasks/Operations

• Relationships between building components and
  tasks/operations

Building components
Building component
Operation
Building components as well as operations and
relationships should be defined in the building
model
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Building Model and Construction Model
Construction Model

• Building Model
• Storey
• S2
• Building component
• BC1
• BC2
• Building component
• BC21
• BC22
• Building comp.
• BC221
• BC222
• ...

Extra Parts
Equipment
Resources
CX1CX2CX3 CX4...
EX1 EX2 EX3 EX4...
RX1 RX2RX3 RX4...
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Selected references

• My own papers
• www.iprod.auc.dk/kaj/documents/common/SystemConce
  pts.pdf
• www.iprod.auc.dk/kaj/documents/common/Bygningsmod
  eller.pdf
• www.iprod.auc.dk/kaj/documents/papers/Exchange.pd
  f
• www.iprod.auc.dk/kaj/documents/papers/ProductFami
  lyModellingForConstruction.pdf
• IAI International Alliance for Interoperability
• www.iai-international.org
• BLIS Project
• www.blis-project.org
• www.blis-project.org/sable

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The end

• Thank you