BIM Summary
Book: Building Information Modelling
Course: 7U4X0
Made by: Sven Berghuis
Chapter 1: BIM: Why? What? How? 4
1.1 Building Information Modeling: Why? 4
1.2 Building Information Modeling: What? 4
1.2.1 BIM in the Design Development Phase 5
1.2.2 BIM in the Construction Phase 5
1.2.3 BIM in the Operation Phase 5
1.2.4 Level of Development 5
1.3 Building Information Modeling: How? 6
1.3.1 Little BIM vs. BIG BIM, Closed BIM vs. Open BIM 6
1.3.2 BIM Maturity Levels 6
1.3.3 BIM Project Execution 7
1.3.4 BIM Roles and Professions 7
Chapter 2: Principles of Geometric Modeling 8
2.1 Geometric Modeling in the Context of BIM 8
2.2 Solid Modeling 8
2.2.1 Explicit Modeling 8
2.2.1.1 Boundary Representation Methods 8
2.2.1.2 Triangulated Surface Modeling 8
2.2.2 Implicit Modeling 9
2.2.2.1 Constructive Solid Geometry 9
2.2.2.2 Extrusion and Rotation Methods 9
2.2.3 A Comparison of Explicit and Implicit Methods 10
2.3 Parametric Modeling 10
2.4 Freeform Curves and Surfaces 11
2.4.1 Freeform Curves 11
2.4.2 Freeform Surfaces 11
Chapter 3: Data Modeling 12
3.1 Introduction 12
3.2 Workflow of Data Modeling 12
3.3 Data Modeling Notations and Languages 13
3.3.1 Entity Relationship Diagrams (ERD) 13
3.3.2 Unified Modeling Language (UML) 13
3.3.3 Extensible Markup Language (XML) 14
3.4 Data Modeling Concepts 14
3.4.1 Entities and Entity Types 14
, 3.4.2 Attributes 15
3.4.2.1 Relationship Modeling 15
3.4.2.2 Object-Oriented Modeling 15
3.4.2.3 XML Data Modeling 16
3.4.3 Relations and Associations 16
3.4.4 Aggregations and Compositions 17
3.4.5 Specialization and Generalization (Inheritance) 17
3.4.5.1 Object-Oriented Modeling 18
3.4.5.2 XML Data Modeling 18
3.5 Challenges of Data Modeling in AEC/FM 19
Chapter 4: Process Modeling 19
4.1 Introduction 19
4.2 Workflow Management 19
4.3 Process Modeling 20
4.3.1 Integration Definition for Function Modeling 20
4.3.2 Business Process Modeling and Notation 21
4.3.2.1 Flow Objects 21
4.3.2.2 Pools and Swim Lanes 21
4.3.2.3 Connecting Objects 22
4.3.2.4 Artifacts 22
4.4 Workflow Management Systems 23
4.5 Execution Processes 24
European standards (from lecture) 24
Chapter 5: Industry Foundation Classes: A Standardized Data Model for the
Vendor-Neutral Exchange of Digital Building Models 25
5.1 Background 25
5.2 History of the IFC Data Model 26
5.3 EXPRESS: A Data Modeling Language for the IFC Standard 27
5.4 Organization in Layers 28
5.4.1 Core Layer 28
5.4.2 Interoperability Layer 28
5.4.3 Domain Layer 28
5.4.4 Resource Layer 29
5.5 Inheritance Hierarchy 30
5.5.1 IfcRoot and Its Direct Subclasses (just read to understand it) 30
5.5.2 IfcObject and Its Direct Subclasses (just read to understand) 31
5.5.3 IfcProduct and Its Direct Subclasses (just read to understand) 31
5.6 Object Relationships 31
5.6.1 General Concept 31
5.6.2 Spatial Aggregation Hierarchy 32
5.7 Geometric Representations 32
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, 5.7.1 Division Between Semantic Description and Geometric Representation 32
5.7.2 Forms of Geometric Description 32
5.7.2.1 Points, Vectors, Directions 33
5.7.2.2 Curves in 2D and 3D 33
5.9 Typification of Building Elements 33
Chapter 6: Process-Based Definition of Model Content 33
6.1 Overview 33
6.2 Information Delivery Manuals and Model View Definitions 34
6.2.1 Process Maps 35
6.2.2 Exchange Requirements 35
6.2.3 Model View Definitions 35
6.2.4 Level of Development 36
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,Chapter 1: BIM: Why? What? How?
BIM significantly improves information flow between stakeholders involved at all stages,
resulting in an increase in efficiency by reducing the laborious and error-prone manual
re-entering of information that dominates conventional paper-based workflows.
1.1 Building Information Modeling: Why?
Line drawings not understood by computers.
- Consistency of the diverse technical drawings can only be checked manually. -> errors
2D drawings: Limited information depthand cannot be directly used by downstream
applications for any kind of analysis, calculation and simulation.
Applying the BIM method -> a much more profound use of computer technology in the
design, engineering, construction and operation of built facilities is realized.
Reducing manual re-entering -> reduce errors -> increase in productivity and quality in
construction projects.
1.2 Building Information Modeling: What?
A Building Information Model is a comprehensive digital representation of a built
facility with great information depth.
-> Typically includes the three-dimensional geometry of the building components at a
defined level of detail.
-> Also comprises non-physical objects, such as spaces and zones, a hierarchical
project structure, or schedules. -> Objects associated with a well-defined set of semantic
information (component type, materials, technical properties, or costs).
BIM describes:
- The process of creating such digital building models
- The process of maintaining, using and exchanging them throughout the entire lifetime
of the built facility.
The most obvious feature of a Building Information Model is the three dimensional geometry
of the facility under design or construction, which provides the basis for performing clash
detection and for deriving consistent horizontal and vertical sections.
3D geometry on its own is not sufficient to provide a really capable digital representation.
No universally applicable definition of what information a Building Information Model must
provide - > the concrete information content depends heavily on the purpose of the model.
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,- Multiple BIM models are used across the project phases.
1.2.1 BIM in the Design Development Phase
BIM advantages:
- Horizontal and vertical sections are derived directly from the model and are thus
automatically consistent with each other.
- Clash detection between the different partial models makes it possible to identify and
resolve conflicts between the design disciplines at an early stage.
- Facilitates the integration of computations and simulations in a seamless way.
- A wide range of simulations, including structural analysis, building performance
simulation, evacuation simulation, or lightning analysis, are then usable in the design
process.
- The model can be checked for compliance with codes and regulations.
- the model data can be used to compute a very precise quantity take-off, providing the
basis for reliable cost estimations and improving accuracy in the tendering and
bidding process.
Applying BIM -> shifting design effort to earlier phases.
The ability to plan coordination requirements in detail and to employ computational analyses
in the early design phases -> makes it possible to evaluate the impact of design decisions
more comprehensively and to identify and resolve possible conflicts early on.
-> significantly decreasing the effort required at later phases and improving the overall
design quality.
1.2.2 BIM in the Construction Phase
4D Building Information Model = the individual building components with the scheduled
construction times.
-> construction sequence can be validated, spatial collisions can be detected and the site
logistics can be organized.
5D = also costs.
1.2.3 BIM in the Operation Phase
All changes in the real facility must be recorded in its digital twin.
When building demolished -> the digital twin provides detailed information about the
materials used in its construction, in order to plan their environmentally-sound recycling or
disposal.
1.2.4 Level of Development
Conventional planning processes -> drawing scale provides a well-established
means for describing the geometric resolution required for a certain project stage which
implicitly defines the degree of elaboration, maturity and reliability of the design information
to be delivered.
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,Level of Detail (LOD)
-> defines both the required geometric detail (also denoted as Level of
Geometry – LOG) as well as the required alphanumeric information (also denoted
as Level of Information – LOI).
-> defines the extent of information provided but also gives an indication of its maturity and
reliability.
1.3 Building Information Modeling: How?
1.3.1 Little BIM vs. BIG BIM, Closed BIM vs. Open BIM
Little BIM: the application of a specific BIM software by an individual stakeholder to realize a
discipline-specific design task.
-> The building model is not used across different software packages and is not handed over
to other stakeholders.
-> An insular solution within one design discipline.
BIG BIM: involves consistently model-based communications between all stakeholders and
across the entire lifecycle of a facility.
Closed BIM: Software products by a single vendor and proprietary formats for data
exchange.
Open BIM: Software products by different vendors and open formats for data exchange.
buildingSMART: Founded to overcome this enormous economic waste and significantly
improve data exchange between software products in the AEC industry.
1.3.2 BIM Maturity Levels
BIM Maturity Model defines four discrete levels of BIM implementation.
-> level 0 to 3.
0: CAD drawings
1: 2D/3D
2: Federated BIMs
3: Integrated BIMs
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, 1.3.3 BIM Project Execution
An important prerequisite for the successful realization of BIM projects are legally binding
agreements addressing model contents, model qualities and workflows, in particular for the
handover of building models to the owner.
Employer’s Information Requirements (EIR)
BIM Execution Plan (BEP)
EIR: the client declares the objectives of applying BIM in the project and how the digital
processes shall be executed -> Contains detailed specifications on responsibilities, handover
dates and procedures, as well as data exchange formats.
BEP: bidders (potential contractors) describe how they plan to meet the requirements of the
EIR -> refined into a more detailed document after the contract is awarded.
1.3.4 BIM Roles and Professions
BIM Manager: a strategic role in the company, responsible for guiding the transition towards
digital practices and for developing guidelines regarding workflows, model contents and best
practices.
BIM Coördinator: is a role assigned on a per-project basis, and is responsible for
coordinating the specialist disciplines, merging sub-models, checking model contents and
applying quality control in order to meet the client’s demands.
BIM Modeler: an engineer or architect responsible for developing the model.
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