There are many truths and myths in the commonly accepted perceptions of BIM's state of the art. We make no claims that the book is objective in our assessment of the necessity of BIM.
EXECUTIVE SUMMARY
INTRODUCTION
THE CURRENT AEC BUSINESS MODEL
- Design-Bid-Build
- Design-Build
- Construction Management at Risk
- Integrated Project Delivery
- What Kind of Building Procurement Is Best When BIM Is Used?
After that, construction begins and all further changes to the design (within predetermined limits) become the responsibility of the DB contractor. The construction manager is usually an approved general contractor and guarantees the cost of the project (maximum guaranteed price or GMP).
DOCUMENTED INEFFICIENCIES OF TRADITIONAL APPROACHES
CIFE Study of Construction Industry Labor Productivity
Labor represents about 40 to 60 percent of the estimated cost of construction (depending on the type of construction). Additions, alterations or alterations represent about 23 percent and maintenance and repair represent about 10 to 12 percent of the building volume.
NIST Study of Cost of Construction Industry Ineffi ciency
In the construction industry, incompatibility between systems often prevents project team members from sharing information quickly and accurately; it is the cause of many problems, including increased costs, and so on. In the NIST study, the cost of insufficient interoperability was calculated by comparing actual business activities and costs to hypothetical scenarios in which there was uninterrupted information flow and no redundant data entry.
BIM: NEW TOOLS AND NEW PROCESSES
BIM Model Creation Tools (Chapter 2)
The scope of BIM directly or indirectly affects all stakeholders supporting the capital facilities industry. The terms Building Information Model and Building Information Modeling are often used interchangeably, reflecting the growth of the term to manage the area's expanding needs.
As a product
As an IT-enabled, open standards–based deliverable, and a collaborative process
As a facility lifecycle management requirement
- Defi nition of Parametric Objects (Chapter 2)
- Support for Project Team Collaboration (Chapter 3)
- WHAT IS NOT BIM TECHNOLOGY?
- WHAT ARE THE BENEFITS OF BIM? WHAT PROBLEMS DOES IT ADDRESS?
- Preconstruction Benefi ts to Owner (Chapters 4 and 5) Concept, Feasibility, and Design Benefi ts
- Design Benefi ts (Chapter 5)
- Construction and Fabrication Benefi ts (Chapters 6 and 7)
- Post Construction Benefi ts (Chapter 4)
- WHAT CHALLENGES CAN BE EXPECTED?
- Challenges with Collaboration and Teaming
- Legal Changes to Documentation Ownership and Production
- Changes in Practice and Use of Information
- Implementation Issues
- FUTURE OF DESIGNING AND BUILDING WITH BIM (CHAPTER 8)
- CASE STUDIES (CHAPTER 9)
It can be used to visualize the design at any stage of the process, with the expectation that it will be dimensionally consistent in every view. These cover the whole range of the building lifecycle, although most focus on the design and construction phases (with extensive illustration of external building models).
Discussion Questions
EXECUTIVE SUMMARY
At the tool level, they differ in the sophistication of their predefined base objects; in the ease with which users can define new object classes; in object update methods; in ease of use; in the types of surfaces that can be used; in drawing generation capabilities; in their ability to handle a large number of objects. At the platform level, they differ in their ability to manage large or highly detailed projects, interfaces with other BIM tool software, interface consistency for using multiple tools, extensibility, external libraries that can be used, and the data they carry to enable management , and their ability to support collaboration.
THE EVOLUTION TO OBJECT-BASED PARAMETRIC MODELING
- Early 3D Modeling
- Object-Based Parametric Modeling of Buildings
- Degrees of Parametric Modeling
In the alternative approach, Constructive Solid Geometry (CSG) represented a shape as a set of functions defining the primitive polyhedra like those defined in Figure 2–3 (left), similar to that for B-rep. The wall ends are defined by the wall's intersection, with either a fixed endpoint (freestanding) or associations with other walls or columns.
At the simplest level is the defi nition of complex shapes or assemblies de- fi ned by a few parameters. This is often called parametric solid modeling
There are also several different types of BIM design applications, with different object classes for handling different building systems. As described in the previous history, several different technologies are combined to provide a modern parametric modeling system.
An incremental improvement is the defi nition of assembly modeling that automatically updates when any shape’s parameters are changed,
There are many detailed differences between the domain-specific parametric modeling tools used in BIM and those used in other industries. These differences have resulted in only a few general parametric modeling tools being adapted and used for building information modeling.
A major improvement allows the parameters defi ning one shape to be linked through rules to the parameters of another shape. Because
- PARAMETRIC MODELING OF BUILDINGS
- Parametric Design
- Parametric Modeling for Construction
- User-Defi ned Parametric Objects
Each of the BIM design applications also includes other objects that are used to modify primary building shell objects. A separate set of BIM design applications has been developed for modeling at the more detailed manufacturing levels.
Creating an object in another system and importing it into your BIM tool as a reference object, without local editing capabilities
Examples are a wall resting on a stepped slab; a spiral ramp with different slopes; rooms with vaulted ceilings. A build system whose structure and behavior are not available from software or build system vendors.
Laying out the object instance manually using solid modeling geometry, assigning attributes manually, and remembering to update the object
Examples are curtain walls and building skin systems; complex room types that integrate expertise into their layout (eg the building core example in Chapter 5) and also laboratories and medical rooms.
Defi ning a new parametric object family that incorporates the appropri- ate external parameters and design rules to support automatic updating
Defi ning an extension to an existing parametric object family that has modifi ed shape, behavior, and parameters; the resulting object(s) fully
Defi ning a new object class that fully integrates and responds to its context
- BEYOND PARAMETRIC SHAPES
- Relational Structures
- Property and Attribute Handling
- Drawing Generation
Although organizations such as the Building Specifications Institute are working on these issues (see Sections 3.4.1 and 3.4.2), the development of property sets to support a wide range of simulation and analysis tools has not yet been properly organized in a standard way. for use; they are currently left up to users to set. BIM design tools provide the means to extract a drawn section at the level of detail to which it is defined in the 3D model. with certain items selectively turned off).
A weak level of drawing production provides for the generation of orthographic sections cut from a 3D model, and the user manually edits
The section is then detailed by hand with the necessary wood blocks, extrusions, silicone beading and weather stripping; and associated annotations in the fully detailed drawn section. In most systems, this detail is associated with the section it was based on.
An improvement upon this level is the defi nition and use of drawing templates associated with elements for a type of projection (plan, section,
The drawing generation can be done either in an external drawing system or within the BIM tool.
Current top-level drawing functionality supports bidirectional editing between models and drawings. Changes to model annotations are the same
- Scalability
- Object Management and Links Object Management
Only a few BIM design applications developed specifically for architecture have the means to manage parametric change propagation across multiple files. Files get big and the project needs to be split up somehow so design can continue; the files are large, slow and cumbersome.
Files become huge and the project must be partitioned in some way to allow design to continue; the fi les are large, slow, and cumbersome
This challenges scalability and places practical limits on the size of a project module that can be effectively edited. Other systems have methods for distributing relationships and updates across files and can open, update, and then close multiple files during an edit operation.
- Some Commonly Asked Questions
- Summary
- BIM ENVIRONMENTS, PLATFORMS, AND TOOLS
- OVERVIEW OF THE MAJOR BIM DESIGN PLATFORMS
- As a BIM Design Tool
- As a BIM Platform
- As a BIM Environment
- BIM PLATFORMS
- Revit
- Bentley Systems
- ArchiCAD
- Digital Project
- Vectorworks
- Tekla Structures
- DProfi ler
- AutoCAD-Based Applications
- LIGHTWEIGHT MODELING APPLICATIONS
- CONCLUSION
This involves the ability of the system to remain responsive regardless of the number of 3D parametric objects in the project. Below we provide an overview of the current capabilities of the major building model generation platforms.
Discussion Questions
EXECUTIVE SUMMARY
Data models distinguish the schema used to organize the data and the schema language used to transport the data. Two important data models for building products are the Industry Foundation Classes (IFC) - for planning, design, construction and management of buildings.
INTRODUCTION
Platform-to-tool exchange is the most fundamental form of interoperability and is supported by direct application-to-application exchange as well as shared neutral exchange formats, such as IFC. They are also promoted and can be used for limited applications as interfaces to other tools, such as light simulation or collision detection.
DIFFERENT KINDS OF EXCHANGE FORMATS
Vector formats vary in compactness, line formatting, color, layering, and supported curve types; some are file-based and others use XML. Some include lighting, camera, and other display controls; some are file formats and others XML.
BACKGROUND OF PRODUCT DATA MODELS
- ISO-STEP in Building Construction
- buildingSMART and IFC
- What Is the IFC?
- IFC Coverage
- IFC in Use—BIM Standards
- Implications of IFC Interoperability
Each level of the tree in Figure 3–6 introduces different properties and relationships to the wall entity. 1Subtyping allows for the definition of a new class constructor that "inherits" the properties of its "parent" class and adds new properties that distinguish it from its parent and make any possible.
OTHER EFFORTS SUPPORTING STANDARDIZATION
- International Framework for Dictionaries
- OmniClass
- COBie
- XML-Based Schemas
Attributes, Type, Material, Classification, Attributes Zone Attributes, Classification, Attributes, Spatial Allocation System Attributes, Classification, Attributes, Component Allocation,. The language binding, for example, the method of how to translate the IFC EXPRESS model into the ifcXML XSD model, follows the international standard ISO 10303-28ed2 "XML representation of EXPRESS schemas and data." The ISO/CD 10303-28ed2 version of is used for the language binding.
THE EVOLUTION FROM FILE-BASED EXCHANGE TO BUILDING MODEL REPOSITORIES
- Project Transactions and Synchronization
Digital Project, V1, R4, SP 7 At object instance level At object instance level Tekla At object instance level At object instance level. Status flags are often kept at the object level to distinguish temporary updates from complete transactions, and also objects that are out of sync.
Automatic Partial Updates: Many derived object views are simple and can be updated automatically. This class of synchronization transaction
Based on such status information, a background transaction identifies which objects have been created, modified, or deleted, and identifies which other files have those objects in them. Alternative mechanisms may be used to mark the affected objects in the various application datasets.
Assigned Action Items: Where automatic updates are not determinis- tic, a manual update transaction is required, such as for some types of
- Functionality of BIM Servers
A design-engineering-construction project-oriented market; this is the kernel market and will be developed in more detail below; it is project-
A facilities operation and management product, addressing the moni- toring of facility operations, possibly capturing sensor data from one or
- BIM Server Review
- SUMMARY
It supports CityGML export of IFC models to CityGML (www.citygml.org/), including the BIM/IFC-Extension (www .citygmlwiki.org/index.php/CityGML_BIM_ADE). It supports spatial program review through two-way exchanges with BIM authoring tools through IFC.
Discussion Questions
EXECUTIVE SUMMARY
Reduce the financial risk associated with the project by using the BIM model to obtain faster and more reliable cost estimates and improve project team collaboration. Ensure program compliance through ongoing analysis of the building model against owner requirements and local code.
INTRODUCTION: WHY OWNERS SHOULD CARE ABOUT BIM
At the same time, owners can benefit from project quality, cost and future operation of the facility. BIM tools are essential for owners to understand the intent and considerations of the designers and builders that make up the IPD team.
BIM APPLICATION AREAS FOR OWNERS
- Design Assessment
- Complexity of Building Infrastructure and Building Environment
- Sustainability
- Cost Reliability and Management
- Time to Market: Schedule Management
- Facility and Information Asset Management
FIGURE 4–3 Snapshot showing the owner (GSA) and judges in a Virtual Reality Cave environment while interactively reviewing the design. According to the Building Commissioning Association (see www.bcxa.org/), "Building commissioning provides documented confirmation that building systems are operating according to criteria specified in the project documents to satisfy the owner's operational needs." The Maryland General Hospital case study (see Chapter 9) describes how the team used a building model, tablet PCs, and custom software to record equipment data and perform the commissioning activities.
BIM TOOL GUIDE FOR OWNERS
- BIM Estimating Tools
- Facility and Asset Management Tools
- Operation Simulation Tools
The Coast Guard Facilities Planning case study in Chapter 9 recorded a 98 percent reduction in time and effort to produce and update the facility management database using a building information model. The use of BIM to support facilities management is in its infancy and the tools have only recently become available on the market.
AN OWNER AND FACILITY MANAGER’S BUILDING MODEL
Figure 4-12 provides a framework for owners to understand the relationship between the level of detail in the model—masses, spaces, and structure-level detail (see vertical direction)—and the scope of the model, including spatial and domain-specific. c elements such as architectural and MEP detail elements. Some of this information is represented in the IFC schema, as discussed in Chapter 3, and there is a working group within IAI, the "Facility Management Domain" (www.buildingsmart.com/content/fm_handover_view_aquarium), which addresses facility-specific scenarios such as are relocation management, work order flows, costs, invoices and financial elements in facilities management.
LEADING THE BIM IMPLEMENTATION ON A PROJECT
- Develop Guidelines for BIM on Projects
- Build Internal Leadership and Knowledge
- Service Provider Selection
- Build and Educate a Qualifi ed Network of BIM Service Providers
- Change Deliverable Requirements: Modify Contracts and Contract Language
Does your organization have specific BIM-related job titles and functions (such as those listed previously). This shows a clear commitment and recognition of the use of BIM in their organization.). One of the challenges for owners is finding service providers capable of BIM technologies within their existing network.
Scope and detail of the model information
Uses of model information
Organization of model information
However, it is often difficult to meet these requirements without some changes in compensation structure and relationships between project participants or without the use of incentive plans that govern workflow and digital transfer between disciplines. These are often more difficult to define in a workflow centered on a digital model, as opposed to files and documents.
