BIM Content Development E-Book

Robert S. Weygant

• Herausgeber: John Wiley & Sons
• Kategorie: Geisteswissenschaft
• Sprache: Englisch

Seitenzahl: 603

Veröffentlichungsjahr: 2011

Beschreibung

From the cutting-edge of technology comes this book on Building Information Modeling (BIM), the newest technology in the AEC industry that allows the professional to create 3D models of a building that includes much more data than a traditional 2D CAD file. Developing BIM Content explains the type of information that can go into a BIM model from a vendor-neutral perspective and explores different methods for organizing content. For anyone interested in creating feature-rich BIM object and models that work on any platform, this is a must-have reference.

Leseprobe

Contents

Introduction : Using this Book

Part I : Getting Started

Chapter 1 : The Mental Transition to Building Information Modeling

BIM—A Whole-Building Approach To Design

CAD vs. BIM

CAD ) SPECS = BIM

Conclusion

Chapter 2 : Content Hierarchy

Understanding Materials, Objects, Assemblies, and Projects

What is A BIM Object?

What is A BIM Assembly?

What Goes into Objects and Assemblies?

What is A BIM Project?

Chapter 3 : Understanding Parameters, Attributes, and Constraints

Parameters

Constraints and Conditions

Chapter 4 : Standards and Formats

The Purpose of Standards and Formats

Masterformat®

Uniformat™

Omniclass

Chapter 5 : Where to Begin

What is it? Materials, Assemblies, Objects, and Details

Implementing the Component: Primary, Secondary, and Tertiary

Data Management Concepts

Naming Conventions

Part II : BIM Content Basics

Chapter 6 : Basic Modeling Considerations

Levels of Detail—AIA E202 and the LOD Concept

Representative Modeling

Using Solid Modeling Tools

Reference Lines and Planes

Dimensions and Tolerances

Developing Content for Clash Detection

Chapter 7 : Creation and Management of Materials

What Are BIM Materials?

Why Materials are Important

Data—What Goes into Materials?

Appearance and Rendering

Chapter 8 : CAD Imports and Nonparametric Objects

Importing CAD Files—PROS and CONS

Nonparametric and Semi-Parametric Objects

Conclusions

Chapter 9 : BIM Data: The “I” in BIM

Types of Information to ADD

Methods of Data Entry

Data Usage

Chapter 10 : Quality Control

Quality Control Procedures

Educating Staff on Quality Control

Chapter 11 : Knowledge Management

What is Knowledge Management?

The Knowledge Manager

New Documents and Deliverables

Chapter 12 : BIM Data and Specifications

Changing Specification Practice

Standards and Formats for BIM

Organizing BIM Data

Process Automation

The Evolving Role of the Specifier

The Ever-Evolving Specification

Changing the Specifier’s Workflow

Conclusions

Part III : BIM Content Types

Chapter 13 : Walls

Anatomy

Considerations

Graphics

Materials

Data—Attributes and Equations

Usage—Leveraging the Information

Example Wall Assemblies and their Attribute Sets

Chapter 14 : Roofs

Anatomy

Considerations

Graphics

Materials Drive the Roof

Data—Attributes and Equations

Usage—Leveraging the Information

Typical Roof Assemblies and their Attribute Sets

Chapter 15 : Floors and Ceilings

Anatomy

Considerations

Graphics

Materials

Data—Attributes, Constraints, and Equations

Usage—Leveraging the Information

Typical Floor and Ceiling Assemblies and their Attributes

Chapter 16 : Windows and Skylights

Anatomy

Considerations

Graphics

Materials

Data—Attributes, Constraints, and Equations

Example Window and Skylight Components and their Attribute Sets

Chapter 17 : Doors

Anatomy

Considerations

Size/Dimensions

Performance

Graphics

Materials

Data—Attributes, Constraints, and Equations

Usage—Leveraging the Information

Example Door Objects and their Attribute Sets

Chapter 18 : Stairs and Railings

Anatomy

Considerations

Graphics

Data—Attributes and Equations

Example Stair and Railing Components and their Attribute Sets

Chapter 19 : Curtain Walls and Storefronts

Anatomy

Considerations

Graphics

Materials

Data—Attributes, Constraints, and Equations

Example Curtain Walls and their Attribute Sets

Chapter 20 : Fixtures and Fittings

Anatomy

Considerations

Graphics

Materials and Finishes

Data—Attributes and Equations

Example Fixture and Fitting Components and their Attribute Sets

Chapter 21 : Lighting

Anatomy

Considerations

Graphics

Materials

Data—Attributes and Equations

Usage—Leveraging the Information

Sample Lighting Components and their Attribute Sets

Chapter 22 : Mechanical, Electrical, and Plumbing Components

Anatomy

Considerations

Graphics and Connections

Example Fixture and Fitting Components and their Attribute Sets

Chapter 23 : Site and Landscape Components

Considerations

Graphics

Materials

Data—Attributes and Equations

Example Site Components and their Attribute Sets

Chapter 24 : Detailing and Annotations

Considerations

Graphics

Data—From Attributes to Annotations

Chapter 25 : Constellations

What Is A Constellation?

Building Constellations

Quality Control—Tips and Best Practices

Constellation Types

Appendix A : OmniClass Table 49 – Properties

Index

Copyright © 2011 by John Wiley & Sons, Inc. All rights reserved

Published by John Wiley & Sons, Inc., Hoboken, New Jersey

Published simultaneously in Canada

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Library of Congress Cataloging-in-Publication Data:

Weygant, Robert S., 1973-

BIM content development : standards, strategies, and best practices / Robert S. Weygant.

p. cm.

Includes index.

ISBN 978-0-470-58357-9 (pbk.); 978-0-470-95133-0 (ebk); 978-0-470-95152-1 (ebk); 978-1-118-03045-5 (ebk); 978-1-118-03046-2 (ebk); 978-1-118-03047-9 (ebk) 1. Building information modeling. I. Title.

TH437.W49 2011

690.0285—dc22

2010047226

Introduction: Using this Book

UNDERSTANDING BUILDING INFORMATION MODELING

What is BIM? Whether we are talking about building information modeling or building information management, BIM is a technology that has improved the way structures are designed and built. Just as CAD (computer-aided design) improved upon hand drafting, BIM is improving upon CAD. The difference is that BIM involves so many more project participants than just the architect. Building information modeling allows the architect to design and detail, the specifier to document, and the contractor to develop far more quickly than previous methods. The owner and facility manager also see tremendous benefits in forecasting and budgeting.

Initially, BIM was viewed as a tool to design in three dimensions and use components rather than lines. In the time that it has evolved, it has grown tremendously, to a tool that is used for model analysis, clash detection, product selection, and whole project conceptualization. Just as the aerospace and automotive industries develop digital prototypes of vehicles, the Architectural, Engineering and Construction (AEC) disciplines are now able to provide a digital representation of a building well before the first dollar is spent or the first shovel hits the ground.

BIM is by no means the panacea for all that ails the AEC communities—it’s simply a better tool for the job. There is no expectation that every component will be accurate to the last screw or that colors will match identically. BIM provides a level of detail necessary to design and construct a specific project under specific conditions, analyze the design for its merits, and determine specific courses of action based on a greater level of detail than was previously available. Until recently, the components used within a BIM project were generic and simple in nature, more like a symbol for a component that is to be used than an exact replica of a specific product. As hardware and software technology improves and the number of involved manufacturers increases, the level of detail and amount of information improve as well.

Manufacturers are becoming more and more involved in BIM because industry trends dictate the necessity of BIM on certain projects. This increases the accuracy of the product information, in turn increasing the accuracy of the project. Some of the greatest benefits of BIM are the ability to analyze the benefits of a specific product when used in conjunction with others, perform space planning based on different sizes of actually available components, and, in many cases, conceptualize exactly what the space will look like once completed.

BASIC DEFINITIONS AS THEY APPLY TO BIM

Building: Any structure, project, system, or space.Information: Knowledge of specific events or topics gathered or received by communication.Modeling: Creation of a schematic description of a system, theory, or design that accounts for its known or inferred properties for further study of its characteristics.Management: The organization and control of something.Building information: Knowledge applicable to a given project, system, or element.Building modeling: Description of a structure, project, system, or space by way of visual and graphic representation.Information modeling: A description of the attributes of a design for further study of its characteristics.Building information modeling (BIM): A technology that allows relevant graphical and topical information related to the built environment to be stored in a relational database for access and management.Building information management (BIM): The collection, organization, analysis, and distribution of attributed data contained within a building project.

WHO SHOULD READ THIS BOOK

Design professionals in the AEC (Architectural Engineering and Construction) communities can leverage the information in this book to implement best practices in their BIM strategy. Since every firm works a bit differently and every project has its own requirements, AEC professionals can develop a set of internal standards that are based on widely accepted formats and principles in use today. By developing new BIM standards based on current standards, the learning curve is made shallower, and interoperability between offices becomes easier.

The AEC communities have the responsibility of actually creating, placing, and managing the content from inception, so the more effort that is put into content creation up front, the less effort is required over time. A well-built window object can last as long as the software, needing little more than periodic modifications to options and underlying product and performance data. Managing the data is the cumbersome part for many, as the data must be kept organized and consistent between specifications, technical data sheets, CAD details, websites, and now BIM objects.

One must consider how this information is to be managed over time. If there is not a singularly qualified individual on staff who can maintain the information, then sourcing or acquisition of BIM content through a hosting agency such as ARCAT.com or Sweets can be a practical approach. These agencies organize multiple manufacturers in multiple product categories so they can be located and downloaded from a single source, rather than our going from website to website searching for specific components when time is short. When downloading BIM content from a manufacturer or content library, it is important to consider important points such as how it was created, the size and quality of the graphics, the amount and accuracy of the information and how dynamic the models are.

Not all content is created equal. Most readily accessible models are lacking a great deal of the product information and formatting necessary to sort and filter the model after it has been created. Regardless of whether the model is created in-house, outsourced, or downloaded for free, without consistent development strategies in place, the ability to provide accurate quantity takeoffs and schedules is diminished considerably. Geometry and graphics are the visible aspect of most any BIM component, but are not necessarily the most important. While the graphics of the model as a whole are critical, certain products need not have accurate graphics, as they are selected and specified based on their performance, not their appearance. This is typical of most mechanical and structural elements and many other architectural elements as well. The type of graphics and the level of information are determined by the individual firm working on a specific project, which has its own requirements and merits. Not all projects require the creation of a true as-built model “digital owner’s manual,” but in terms of content, it is always better to have the detail and data and never use them than to need them and not have them. Contractors are a driving force behind the growth of building information modeling. Some of BIM’s greatest improvements to the construction industry as a whole are felt by the contractors, subcontractors, estimators, and supply-chain personnel. It is not uncommon to see a general contractor take a set of two-dimensional drawings and create a model prior to construction in order to affirm the constructability of the structure and analyze the model for phasing and estimation purposes.

BIM software has the ability to perform interference checking or “clash detection,” which determines when the locations of two elements are in conflict with each other. In the case where a drain pipe runs across a floor for any length, it will slope downward to allow water to flow. If the pipe does not clear a structural member as it attempts to pass below it or if it interferes with the structural member, a “clash” is detected and the user is notified. This type of design conflict is difficult to spot and easily missed when dealing with several two-dimensional drawings. Determining these types of clashes saves contractors and owners millions of dollars and countless hours annually versus traditional design methods.

Phasing a model is a functionality that allows the contractor to record progress digitally and plan logistics accordingly. When products are to be brought on site, they need storage facilities that can accommodate them until they are installed. As they are installed, designing a specific workflow pattern ensures that subcontractors are not on top of each other. Phasing a project within a BIM model allows the contractor to find the closest and most appropriate storage locations and workflow patterns to minimize excess hours and fatigue associated with effort to move equipment and materials.

BIM data can be used by contractors to simplify estimation by automating quantity takeoffs, perform clash-detection studies to confirm that the design is buildable, and ultimately minimize errors and change orders. Building products are the building blocks of every construction project and, thus, the building blocks of a BIM project. Not only does BIM provide a new conduit through which products can be marketed and sold, it can simplify the processes by which supply-chain and sales personnel handle product ordering and distribution. Conceptualizations allow actual products to be placed in a model to determine size and aesthetic considerations, and, as products are placed within a project, they are quantified and organized in neat schedules. The details that differentiate the products are listed and the links to additional data and contact information are embedded within the model for reference.

BIM is different from CAD in terms of its function and purpose. While CAD drawings for manufacturers’ products show every last detail, BIM is designed for the benefit of the architect and those implementing the product. This drastically limits the graphic representation of the product to only that information necessary to the architect for design and implementation. As product models are created, it’s important to realize that they are not typically exact replicas of the product, but more of a symbol to represent the overall space the component takes up. The major appearance details are shown graphically, while the minor details are shown in terms of data in the model or omitted altogether where deemed unnecessary. Think of the component in terms of its scale in relation to the overall project. A general rule of thumb is to model the graphic elements that are visible when viewed from 10 to 15 feet away in their installed position.

Data drive the success or failure of BIM for manufacturers. While graphics are important within the model, a manufacturer wants to see his product specified and ultimately installed in the project. If we can’t count the number of components used or even determine their names, providing the models in a BIM format is no different than using a symbol that comes with the software right out of the box. The identification information surrounding the actual products, using actual materials with actual sizes, is only the entry point for a good BIM component. Throughout this book, we will discuss the types of additional information necessary, how it can be used, and why it should be associated with the model.

I caution manufacturers against adding cost information into a model, as prices fluctuate constantly and it may be several months or even years from the time the model is created until the project is actually ready for construction. Adding cost information to an individual component can (and usually will) lead to headaches. It also cannot take into consideration the installation or labor costs associated with the project, so this value is best left to an estimator who may be leveraging the model for cost forecasting. Another pitfall with cost information is that without all components in the project tagged with cost information, the overall valuation will be inaccurate. The best method for costing within a BIM is still to perform square foot cost based on the assemblies used within a project. Organizing the components with their appropriate Uniformat and MasterFormat codes allows cost information to be easily derived from the model. Owners and facility managers can be provided with a “digital owner’s manual” of a facility, providing them with the ability to schedule maintenance, forecast and budget for replacements, and track various usage throughout the lifecycle of the facility. Imagine a user interface that would allow us to point and click on a specific light fixture and turn it on or off, or find the camera nearest to a fire alarm that has just sounded. It all starts with a solid BIM that has been developed using actual components with the appropriate amount of information.

Regardless of the software used or the amount of information contained within the model, any BIM will be able to provide size, shape, and location information for components found within the project. At bare minimum, square footage and unit counts are available to analyze. Adding the attributed information about which specific components were used on the project allows for more detailed analysis and a more accurate basis from which to derive cost and replacement information. Basically, the more information that is put into the model, the more detailed is the analysis that can be performed.

WHAT TO EXPECT FROM THIS BOOK

BIM Content Development—Standards, Strategies, and Best Practices has been written to consider all members of a BIM-based project. The concepts within this book are meant to assist all parties—architects, specifiers, contractors, facilities managers, and owners—in developing and leveraging appropriate BIM content. Each member of the project has a different role and requires different information to perform his task. While the architect or design team is ultimately responsible for creating the model, the downstream users of the information contained in the model are of equal importance. Creating tools that allow the architect to pass information through the model to the downstream users of the model integrates everyone associated with the project into a singular team in which all benefit from BIM technology. The figure shows a typical hierarchy of information as it is passed from person to person during the project cycle.

This book is not meant to be a how-to guide for specific software platforms, but a ready reference guide on best practices and principles that apply to all BIM software. Each type of software has advantages and limitations, so from the practices and principles contained within this book, we can extend the knowledge to our software of choice and implement the portions that apply to a given situation.

Project information flow

Every firm and every project is different, so it is unlikely that anyone will use every part of this book on a single project or in a single practice. The level of information and detail necessary for a given situation will vary, and since implementation of practices from the book is very much à la carte, specifics of content development for the different categories are organized in a ready-reference format in Part III. Basic concepts of content development are approached from an angle that balances functionality and accuracy to provide the most effective BIM solutions for every member of a project. Content types are viewed with considerations of developing the materials used, the graphics or geometry that are drawn, the types of data and information necessary for a given category of an element, and potential ways to leverage the element effectively.

Management and organization of content is an essential aspect of creating BIM components. Once the components are created, they are reusable, so long as the information about the products remains current. Every time a product or a system’s performance values change, or every time a product or option is added or eliminated from a manufacturer’s offering, the models must change accordingly. Maintaining this type of information is no easy task, so keeping a clear and simple organizational structure of the product information is critical to the long-term functionality of the components.

Industry standards and formats for information management exist for many organizations. For the construction industry, CSI MasterFormat and Uniformat are the most widely accepted formats. They organize construction information based on the work results and types of construction elements within a structure. In terms of BIM, standards and formats such as these provide ready access filters with which to sort and organize large amounts of information quickly and easily. These formats organize the information that is necessary to determine what product was selected, but cannot qualify why and how a product was chosen over another. This type of information is necessary in determining which products to use for a specific set of conditions, so additional formats are both available and being developed to manage this type of information. BIM Content Development—Standards, Strategies, and Best Practices gives an in-depth look at the different standards available, how and where to implement them in BIM content, and how to leverage the information once the standards are added to BIM projects.

Throughout the book, you’ll find TIPS, which will help you make decisions about what to put in a component, how to think about its development, and, in some cases, whether or not it’s actually necessary.

FUTURE OF BIM

Building information models are driven by the components or content used to build them. A BIM project is best described as a digital representation or prototype of what is to be built. The use of real-world products allows us to analyze the performance and aesthetics of a building before it is built in order to confirm design intent. The ability to perform this type of analysis is controlled mainly by the level of detail and accuracy that goes into the content. This, among other things discussed in the book, is what differentiates a BIM project from a traditional CAD-based project.

The wall, floor, ceiling, and roof are primary components that make up the core and shell of a building. These elements carry the information necessary to determine and outline spaces within a structure, and the overall form the building will take. In addition to their graphical aspects, these components have the ability to carry the information about their individual compositions or makeup, from limitations of their usage to the performance aspects that help us determine why a specific configuration was selected.

Mechanical, electrical, and plumbing components are used to develop entire systems within a building, which allows powerful analysis to be performed from HVAC load calculations to balancing a circuit panel, to laying out the most effective domestic water and fire protection systems. Every component used from the longest pipe to the smallest fitting can be accounted for, which simplifies the estimation process considerably. All of this analysis, though, is dependent on properly created and formatted content.

Beyond the core and shell of a building and the systems contained within are the components that amass to form the building. Products such as doors and windows, fixtures and fittings, furnishings and equipment, and lighting provide a conceptualization of the actual building and the information used to select the products. Openings such as windows and doors are selected and specified based on specific performance criteria and affect the overall energy performance of a building based on such criteria. Embedding performance data into a model allows the designer to actively specify and analyze the model based on the actual product used. This simplifies product selection and specification by allowing a designer to test the use of a various products to see how each will perform.

Ultimately, BIM is a technology that allows us not only to create visual simulations of a project, but to provide a digital prototype of a building prior to construction. Just as no jet aircraft would roll off of the assembly line before it is fully tested, BIM allows a building to be built and tested before the first pile is driven into the ground. Without appropriate content to use for model analysis, a bottleneck is formed. Currently, a great deal of the content available is limited in the amount of actual performance information available to leverage. Throughout the book, you will find tips, tricks, and best practices for adding information into the models to enhance its functionality without overburdening the overall project.

PART I

Getting Started

CHAPTER 1

The Mental Transition to Building Information Modeling

BIM—A WHOLE-BUILDING APPROACH TO DESIGN

Building information modeling changes the way architects, engineers, and contractors work today. It promotes collaboration among all members of a project team, and opens the door for additional members to add relevant information to the design before considerable development has occurred. In traditional two-dimensional drawing, the design and documentation are disjointed in that there is no real relationship between a window and a wall, a wall and a roof, or the roof and the outdoors. BIM allows the design to be looked at as a whole, rather than as individual components that show up on some schedule that was manually created.

The design process no longer consists of lines that represent and enclose spaces and symbols that represent building components. Rather than drawing a series of lines that represent the location of a wall, we can draw the wall itself as a single unit, carrying all of the components and layers associated with it. Floors, ceilings, and roofs are drawn as the areas in which they exist, with the ability to add a specific slope, thickness, and type, as well as identify every component of the assembly. Rather than symbols being used to represent building components in a project, such as windows, doors, fixtures, and fittings, a graphic representation of the component is placed at its appropriate location. These components may be trained to understand how they are to be placed within the project, what they are, and how they relate to adjacent elements in the project.

Openings such as windows and doors are elements placed in a wall to allow the passage of light, traffic, and, in some cases, air. As a window or door is placed into a project, it is trained to remove a specific volume from the wall based on its determined rough opening. Since the window or door is typically not as thick as the wall itself, it allows the user to look at or through the opening from different three-dimensional views, providing a realistic perspective of the building. As components are placed into a model, and volume is removed from the host component, in this case a wall, the information is stored within the software so it may be retrieved later. The type and counts of each component are noted, as well as their dimensions, areas, and locations. Above and beyond visualization and conceptualization of a project, this type of information may be leveraged for square foot cost estimation early in the project, and more accurate quantity takeoffs during bidding. depicts the relationships between two-dimensional linework and three-dimensional modeling.