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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