New Tools Deliver BIM Data
Building model yields valuable information.
By H. Edward Goldberg, AIA
Cadalyst,
December 2003
All the recent hype about BIM (building
information modeling) piqued my curiosity about just how capable this
generation of software is at producing useful information. Conceptually,
BIM, a term coined by Autodesk and promoted by Jerry Laiserin, is
a 3D virtual building model. Data associated with the model contains
information on all building components. This data is available for
use throughout the entire building cycle-the design, construction,
and facility management stages of a project.
To my surprise, I uncovered several software
solutions that extract information from a BIM. This article discusses
some of these options, specifically Autodesk's Revit and Architectural
Desktop 2004, Bentley Architecture 8.1, Graphisoft's ArchiCAD 8.3,
and InterSpec's e-SPECS.
UNDERSTAND THE FORMAT
A better understanding of the nature of these information solutions
requires familiarity with the CSI MasterFormat and UniFormat numbering
systems, the IFC (Industry Foundation Classes) standard, and the ODBC
(open database connectivity) format. The CSI MasterFormat standard
is a 16-division, material-specific organizational format. The UniFormat,
a more detailed numbering system, breaks building systems into categories
such as foundation, superstructure, shell, and interior construction,
and into subcategories such as floor and roof construction and exterior
walls and windows. AEC designers use both systems to organize documents
and specifications. (See CSINet for a more complete explanation of
these formats.)
The IFC standard was developed by the IAI
(International Alliance for Interoperability) to handle 3D file data.
Major CAD vendors helped develop the standard and the tools to support
it. The IAI is a division of the ISO (International Standards Organization),
the body that controls the IGES and STEP data standards.
The IFC system is a data representation
standard and file format used to define architectural and construction-related
CAD graphic data as 3D real-world objects. Its main purpose is to
provide architectural CAD users with the ability to exchange data
between complementary applications such as CAD and estimating tools.
The IFC system provides a set of definitions for all object element
types encountered in the building industry and a text-based structure
for storing those definitions in a data file. It uses a plain text
file, the only truly universal computer data format. Individual CAD
developers store data in whatever compact binary file format best
suits their system. To implement the IFC standard, each CAD company
must create programming within its own software structure. The developers
provide Save As IFC and Read IFC commands, which map the IFC object
definitions to their CAD system's representations of these objects.
As of this writing, Graphisoft and Bentley
have implemented and enabled export capabilities for IFC 2. Bentley's
building applications support 2.x, the latest version of the IFC standard.
In addition, Timberline's estimating software, CAD Integrator Module,
supports the IFC 2 standard for import of IFC data from any IFC application.
ODBC format is a standard database access
method developed by Microsoft. The goal of ODBC is to enable access
to any data from any application, regardless of the DBMS (database
management system) handling the data. ODBC inserts a middle layer,
called a database driver, between an application and the DBMS, which
translates the application's data queries into commands that the DBMS
understands. Both the application and the DBMS must be ODBC-compliant-that
is, the application must be capable of issuing ODBC commands and the
DBMS must be able to respond to them.
GRAPHISOFT'S ARCHICAD 8.3, RCC UNIFORMAT
DATABASE
A compelling third-party software solution that leverages BIM recently
appeared on my radar screen. Rich Creveling, a programmer in Colorado
with a construction industry background, created the RCC UniFormat
Database, a product that bridges the gulf between 3D models created
in ArchiCAD 8.3 and Timberline Estimating Software. RCC's integration
with Timberline estimating software via IFC 2 exchange is a significant
and powerful innovation. The RCC Favorites Library component of the
RCC UniFormat Database is now included with ArchiCAD 8.3 (figure 1).
Figure 1. ArchiCAD 8.3 includes the RCC Favorites Library component
of the RCC UniFormat Database.
The RCC includes a large body of architectural
content such as beams, columns, doors, slabs, walls, windows, floors,
decks, and roofs. As an example of its vastness, the library defines
more than 80 types of typical wall composites. Using the IFC-based
Timberline CAD Integrator, you can leverage building models created
with the ArchiCAD RCC Favorites Library to derive detailed commodity-level
construction cost estimates in seconds.
Because the RCC UniFormat Database and accompanying
object library definitions support the IFC 2 standard, they provide
machine- readable architectural content for automated cost estimating.
This data also features attributes you can use to integrate purchasing,
scheduling, and accounting applications. According to Creveling, he
has had discussions with other design software vendors, including
Bentley Systems, about developing similar object libraries for their
products. He's happy to continue to work with Graphisoft because he
believes that Graphisoft has done a great job of developing ArchiCAD
from the ground up to support IFCs.
The RCC Database builds information to UniFormat
level 6, encompassing stud counts, amount of mortar, lengths of rebar,
and so forth. For about $4,000, you can purchase the RCC Database.
This, along with Timberline's Estimating Software and CAD Integrator,
allows you to output any type of estimate in about 60 seconds (figure
2).
Figure 2. The RCC UniFormat Database, working withTimberline's Estimating
Software and CAD Integrator, outputs any type of estimate in about
a minute.
What-if estimates are available at any
stage of design, and the estimate changes as you modify the design.
AUTODESK REVIT
Revit offers two ways to generate estimating quantities. It can automatically
label quantities with UniFormat II classification Level 4 information,
such as material, area, and volume (figure 3).
Figure 3. Revit generates estimating quantities that are automatically
labeled with UniFormat II classification level 4 information, such
as material, area, and volume.
One method exports to ODBC format. Using
this format, you can export to Microsoft Access database software
all the data contained in Revit's 3D building model, an extensive
list of footings, piers, walls, roofs, windows, doors, finishes, and
furniture. From the OBDC output, you can craft custom database spreadsheets
that automatically create and update estimates. Autodesk's Ken Stowe,
product manager for construction, has created creditable estimates
using this output. Any third-party estimating, planning, procurement,
and facility management tools that use the ODBC format can work with
Revit data.
The second method uses preprocessed, user-defined
ASCII BOM (bill of materials) tables. You can use comma-delimited
output from Revit's standard schedules to provide data for Microsoft
Excel and other spreadsheets. You essentially have two choices: format
your quantities output inside Revit and export it, or export it and
then format your data.
For 4D construction simulation, you can
tag all of Revit's objects with construction-sequence information,
so you can generate 4D storyboards and animations with logistics,
equipment, and safety elements for presentations and owner decision-making
meetings.
AUTODESK ARCHITECTURAL DESKTOP 2004
There are probably more seats of Architectural Desktop in use than
any other architectural CAD software. For software subscribers, the
new Interoperability and Productivity Extension provides enhanced
design workflow tools and smooth data sharing among team members.
Do you need to distribute more than just
graphic data? With DWF files, you can view nongraphic information
as well as design graphics to make design intent more clear. The free
Autodesk Express Viewer displays nongraphical data such as the fire
rating of a door and the square footage of a room. The DWF format
also lets design team members review and redline, making DWF an efficient
means to distribute and share data.
Using Autodesk MapGuide, you can convert
pertinent digital design data contained in Architectural Desktop drawings
into informative and interactive facility maps (figure 4).
Figure 4. Autodesk MapGuide transfers Architectural Desktop design
data into informative and interactive facility maps.
With this tool, you can give other industry
professionals, such as facilities managers, quick access to building
areas and their corresponding resources.
Autodesk Architectural Desktop now exports
the data in drawings to Microsoft Access, where you can view, sort,
query, and export it to other applications to perform specific tasks,
such as cost estimation.
Often forgotten are Architectural Desktop's
scheduling features, which provide the ability to generate BOMs and
basic estimates directly in the model. The objects support a cost
property so you can, for example, wcreate a door schedule that includes
individual and total cost for doors. An IFC 2.x plug-in is available
for ADT.
BENTLEY'S BUILDING SOLUTIONS
Bentley approaches BIM with a multidisciplinary set of solutions.
Bentley Architecture, the architectural design and documentation application,
supports IFC information exchange. Bentley's building solutions are
built on MicroStation and incorporate TriForma technology. Because
of this, each application does full quantity takeoffs and cost estimating
in conjunction with tools such as Excel or Access. You can exchange
information in a variety of formats, including DWG and XML.
Bentley supports MasterFormat and UniFormat,
and its new IFC capabilities should add even more flexiblity. It would
be great to see the RCC database work with Bentley Architecture-that
would truly demonstrate the value of IFCs for common data exchange!
Bentley's Schedule Simulator was probably
the first commercial 4D product for AEC when it debuted several years
ago. The latest version is now included in Bentley Navigator. With
its automated interference detection tools, Schedule Simulator lets
you link model objects to schedule tasks in Microsoft Project or Primavera
P3 so you can present and analyze your design throughout construction.
Bentley Facilities, made for building operations
and management, is fully integrated with Bentley's design tools and
supports AutoCAD drawings. It extends the use of a building model
into the operational life of the building, with full space and asset
management capabilities as well as interactive facility maps, all
accessible through just a Web browser.
INTERSPEC E-SPECS For AutoCAD and
Architectural Desktop users, InterSpec's e-SPECS automates specifications
by extracting product and material requirements directly from the
project drawings (figure 5).
Figure 5. e-SPECS automates specifications by extracting product and
material requirements from project drawings.
For unique items, e-SPECS links to Master
Guide specifications and presents only the language required to specify
the product or material identified. It can even link to existing office
masters and create custom office masters on the fly, eliminating any
compromises on quality and accuracy created by cutting and pasting
sections from previous projects. The old method carries an inevitable
risk of including irrelevant language or excluding relevant language.
Incomplete, poor-quality, and inaccurate specifications can affect
value engineering in design and potential construction cost savings,
as well as increase exposure to litigation.
Using e-SPECS, an entire project team can
collaborate on specification documents from anywhere. Team members
access the project using e-SPECS on their computer or from any Web
browser to review and edit specifications and create and respond to
project notes. e-SPECS version control tracks all user edits and makes
it possible to incorporate comments and changes from multiple sources.
HOW IMPORTANT IS INFORMATION FROM A BIM?
One goal of all the solutions mentioned here is to let you track construction
costs during the design phase and offer alternative concepts based
on budgets. This raises the question, "Can I increase fees for the
additional service of answering these what-if questions during the
design process?" Having instantaneous access to data embedded in the
design should also shorten the bid process, potentially decreasing
bidding costs.
All these savings accrue to the client and
the contractor. Though it's easy to appreciate the inherent value
of the information, at this early stage in technology development
you can only speculate on the monetary value of this information to
the profession of design and the practice of architecture.
In this shifting paradigm, with no existing
corollary, the ultimate effect on the bottom line-whether or not you
can ask for compensation for all the nongraphical information included
in the building model-is the next uncharted territory.
© 2003, CADALYST Magazine
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