There are many truths and myths in the commonly accepted perceptions of the state of the art of BIM. Six of the case studies were originally prepared by graduate students in the College of Architecture at Georgia Tech;.
ACKNOWLEDGMENTS
EXECUTIVE SUMMARY
When complete, the computer-generated model contains the exact geometry and relevant data needed to support the construction, fabrication and procurement activities necessary to realize the building. BIM also accommodates many of the functions needed to model the life cycle of a building, providing the basis for new construction skills and changes in roles and relationships between a project team.
INTRODUCTION
It then explains both the technology behind BIM and recommends ways to best utilize the new business processes it enables throughout a building's lifecycle. We provide a brief description of the kinds of problems that BIM can solve and the new business models it enables.
THE CURRENT AEC BUSINESS MODEL
- Design - Bid - Build ( DBB )
- Design - Build ( DB )
- What Kind of Building Procurement Is Best When BIM Is Used
Subcontractors selected by the contractors must follow the same process for the part of the project they are involved in. After that, construction begins and all further changes to the design (within predetermined limits) become the responsibility of the DB contractor.
DOCUMENTED INEFFICIENCIES OF TRADITIONAL APPROACHES
- CIFE Study of Construction Industry Labor Productivity
- NIST Study of Cost of Construction Industry Ineffi ciency
Existing problems in the construction industry also include issues that are not related to the use of advanced technologies. Widespread adoption of BIM and the use of a comprehensive digital model throughout the life cycle of a building would be a step in the right direction to eliminate such costs arising from inadequate data interoperability.
BIM : NEW TOOLS AND NEW PROCESSES
- BIM Model Creation Tools (Chapter 2 )
- Defi nition of Parametric Objects (Chapter 2)
- Support for Project Team Collaboration (Chapter 3 )
Consistent and non-redundant data so that changes to component data are represented in all views of the component. Furthermore, there are no current implementations of BIM software that meet all the BIM technology criteria.
WHAT IS NOT BIM TECHNOLOGY
Models composed of multiple 2D CAD reference files that must be combined to define the building. This allows errors in the model that are very difficult to detect (similar to overwriting a formula with a manual entry in a spreadsheet).
WHAT ARE THE BENEFITS OF BIM ? WHAT PROBLEMS DOES IT ADDRESS?
- Pre - Construction Benefi ts to Owner (Chapters 4 and 5 )
- Design Benefi ts (Chapter 5 )
- Construction and Fabrication Benefi ts (Chapters 6 & 7 )
- Post Construction Benefi ts (Chapter 4 )
It can be used to visualize the design at any stage of the process with the expectation that it will be dimensionally consistent in any view. The effect of a proposed design change can be entered into the building model, and changes to the other objects in the design will automatically update.
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
The use of BIM will also encourage the integration of construction knowledge earlier in the design process. Effective use of BIM requires making changes to almost every aspect of a firm's business (not just doing the same things in a new way).
FUTURE OF DESIGNING AND BUILDING WITH BIM (CHAPTER 8 )
Start using the BIM system on one or two smaller (perhaps already completed) projects in parallel with existing technology and produce traditional building model documents. Extend the use of BIM to new projects and start collaborating with external project team members in new collaborative approaches that enable early integration and knowledge sharing using the building model.
CASE STUDIES (CHAPTER 9 )
EXECUTIVE SUMMARY
Most architectural BIM design tools allow users to mix 3D modeled objects with 2D drawn sections, allowing users to define the level of 3D detail while still being able to produce complete drawings. This chapter provides an overview of the main BIM model generation tools and some functional differences that can be used to evaluate and select between them.
HISTORY OF BUILDING MODELING TECHNOLOGY
- Early 3D Modeling of Buildings
- Object - Based Parametric Modeling
- Parametric Modeling of Buildings
- User - Defi ned Parametric Objects
- Design - for - Construction
- Object - Based CAD Systems
A fairly complete list of predefined object families provided by the main BIM architectural design tools is given in Table 2-1 (as of early 2007). The final design of the stadium is also shown in the lower part of Figure 2-8.
VARIED CAPABILITIES OF PARAMETRIC
- Topological Structures
- Property and Attribute Handling
- Drawing Generation
- Scalability
- Open Questions
If the windows are placed on the wall according to the offset from the wall - the bottom to the center of the window, the default dimensioning will be done in this way in the subsequent drawings. Connections in mathematics are called topology and - distinct from geometry - are critical to the representation of a building model and one of the fundamental aspects of parametric modeling. Because of this non-redundant representation of the building, all drawings, reports and analysis data sets are consistent if taken from the same version of the building model.
The sheet layouts are maintained in different sessions and are part of the overall project data. If drawings are a specialized representation of the model data, then shape changes in the drawings should be as well. When displayed in windows next to views of the 3D model, updates in any view can be immediately referenced in the other views.
Scalability is affected by both the size of the building, say in floor area, and also by the level of detail in the model. This chapter provided an overview of the basic capabilities of BIM design tools resulting from their development as object-based parametric design tools.
- Discriminating Capabilities
- BIM Tools for Architectural Design
At this early date, attempting to adopt any of the available BIM design tools is a significant undertaking and will be discussed in later chapters. Because the functionality of BIM design tools changes rapidly, it is important to review reviews of the current versions in AECBytes, Cadalyst, or other AEC CAD journals. This means that the system can remain interactive and responsive regardless of the number of parametric 3D objects in the project.
Below we provide an overview of the current capabilities of the main platforms for building model generation. Each rating is for the stated version of the software system; later versions may have better or worse capabilities. The support system is in addition to the user-provided documentation and online support built into the BIM tool.
Bentley Systems Strengths: Bentley offers a very broad range of construction modeling tools that address almost every aspect of the AEC industry. It has a predefined set of architectural objects, and although it is not fully parametric, it provides much of the functionality offered by .
CONCLUSION
Discussion Questions
- EXECUTIVE SUMMARY
- INTRODUCTION
- DIFFERENT KINDS OF EXCHANGE FORMATS
- BACKGROUND OF PRODUCT DATA MODELS
- IFC Relation to STEP
- Organization of IAI
- What Are the IFC s?
- IFC Coverage
- IFC in Use
- Implications of IFC Use
- The Future of IFC
- XML SCHEMAS
- PORTABLE, WEB - BASED FORMATS: DWF AND PDF
- FILE EXCHANGE VERSUS BUILDING MODEL
- SUMMARY
An overview of the most common exchange formats in the AEC area is listed in Table 3 - 1. AP 225 – Building elements with explicit form representation – the only finished building-oriented product data model developed and approved by TC184. Subtyping allows defining a new class of building objects that 'inherits' the properties of its 'parent' class and adds new properties that make it distinct from its parent and any.
Each of the geometric shapes in the system architecture diagram in Figure 3-2 identifies a set of EXPRESS language entities, enumerations, and types. Both efforts focus on specifying IFC views - specific subsets of the IFC - to be used for specific workflow exchanges. In the 2007 AIA BIM Awards program, administered by the Technology in Architectural Practice Knowledge Community, six of the 32 project entries utilized the IFC.
BLIS-XML is a subset of IFC Release 2.0, developed to support a small number of use cases. This is due to the fundamental heterogeneity of the built-in behavior in the parametric modeling design tools (described in Section 2.2.7).
Discussion Questions
On the one hand, all BIM design tools now support IFC quite well, allowing basic exchanges to be performed with sufficient completeness and accuracy. On the other hand, formats like DWF and PDF have the potential to become richer and support both exchange and display.
Discussion Questions (Continued)
- EXECUTIVE SUMMARY
- INTRODUCTION: WHY OWNERS SHOULD CARE ABOUT BIM
- BIM APPLICATION AREAS FOR OWNERS
- Cost Reliability and Management
- Time to Market: Schedule Management
- Complexity of Building Infrastructure and Building Environment
- Sustainability
- Overcoming Labor Shortage, Education, and Language Barriers
- Design Assessment
- Facility and Information Asset Management
- TYPES OF OWNERS: WHY, HOW OFTEN, AND WHERE THEY BUILD
- The BIM Business Case
- Operating Owners vs. Developer Owners
- When Owners Build: One - Time or Serial
- HOW OWNERS BUILD
- Design - Bid - Build
- Design - Build
- Collaborative Process
- Internal or External Modeling
- BIM TOOL GUIDE FOR OWNERS
- BIM Estimating Tools
- Model Validation, Program, and Code Compliance
- Project Communication and Model Review Tools
- Model Viewing and Review
- Model Servers
- Facility and Asset Management Tools
- Operation Simulation Tools
- AN OWNER AND FACILITY MANAGER ’ S BUILDING MODEL
- LEADING THE BIM IMPLEMENTATION ON A PROJECT
- Build Internal Leadership and Knowledge
- Service Provider Selection
- Build and Educate a Qualifi ed Network of BIM Service Providers
- Change Deliverable Requirements
- BARRIERS TO IMPLEMENTING BIM : RISKS AND COMMON MYTHS
- Process Barriers
- Technology Risks and Barriers
- GUIDELINES AND ISSUES FOR OWNERS TO CONSIDER WHEN ADOPTING BIM
Many of the case studies discuss projects where a service provider started using BIM. The participation of all project participants in the creation, revision and updating of the building information model forces the participants to work together and virtually build the project. In such cases, as discussed in section 4.9, the owner must first assess their internal capabilities and work processes.
The owner can mandate the scope and level of detail required for post-construction use of the model. Which organizations collaborated with you in the creation, modification and updating of the building model. What were the lessons learned and statistics measured on these projects regarding the use of the model and BIM tools.
This indicates a clear commitment and recognition of the use of BIM in their organization. This can be based on the geometry of the project site (Northeastern section) or the building structure (East Wing, Building X). It is often difficult to ensure that all project participants have the knowledge and willingness to participate in the creation or use of the building information model.
The management of this process and the related management of the model becomes critical to the project.
Discussion Questions
- EXECUTIVE SUMMARY
- INTRODUCTION
- SCOPE OF DESIGN SERVICES
- The Concept of Information Development
- Technical Collaborations
- BIM USE IN DESIGN PROCESSES
- Concept Design and Preliminary Analyses
- Building System Design and Analysis/Simulation
- Construction - Level Building Models
An overview of the services provided within the traditional design phases is shown in Figure 5 - 1. Two of the case studies in Chapter 9—the Beijing Aquatic Center and the San Francisco Federal Building—are examples of high-information development projects. A single floor plan and schematic dimensions of the entire building are also shown in Figure 5 - 4.
At present, most of the information generated by these tools must be regenerated in the transfer to a BIM authoring tool. First, we focus on the use of such applications as part of the normal process of performance evaluation during the detailing of building systems in the later stages of design. Such adaptation of the IFC model can be expected as BIM technology becomes more widely adopted.
The built space can contribute to the efficient functioning of the activities carried out in the building. This method was used in the structural optimization of the Beijing Aquatics Center (see Chapter 9.
