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What is BIM and why should I care about
it?
by Stephen Spangler, US Army Corps
of Engineers’ Engineer Research and Development Center
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| Stephen Spangler, US Army Corps
of Engineers |
BIM, BIM, BIM. Building Information Modeling.
Unless you have been hiding under a rock — or with respect
to the design world, under your drafting desk — you have
at least heard of or read about BIM technology. If you attend
any of the big CAD vendor conferences, such as the BE Conference
or Autodesk University, you are probably starting to notice
that the number of presentations on CAD is dwindling and the
number of presentations on BIM is growing. "So what,"
you may be thinking, "my company is one of the foremost
companies in the use of CAD technology." This article
will provide a brief explanation of what BIM technology is
and why you probably should be taking an interest in it.
What is BIM?
First off, BIM most accurately stands for Building Information
Modeling. You may also see it defined as Building Information
Model, but I think this is inaccurate since models are one
of the many products of BIM. If I had to compare CAD technology
to BIM technology, I would say BIM is to CAD, as CAD was to
hand drafting. BIM represents a significant technology leap
in the capturing of design information about a building or
structure.
On a side note, before those people who design structures
other than buildings start to tune out, BIM is not just for
buildings. I work for the US Army Corps of Engineers and BIM
technology has already been successfully used to model not
just buildings, but civil works projects such as locks and
dams. Any type of structure can be modeled in BIM. Perhaps
one day BIM will be renamed as Structure Information Modeling,
Facility Information Modeling or Design Information Modeling.
(Well, scratch that last one, DIM is not exactly the best
acronym to have tied to a technology.)
The Tao of BIM
One common misconception is that CAD is for 2D design and
BIM is for 3D design. This is definitely not the case, since
you can easily create 3D designs with CAD technology. The
main difference between CAD and BIM all comes down to how
an object perceives itself after it is placed. For instance,
in CAD when you draw a wall, you may possibly draw one line
then copy parallel that line a certain distance to achieve
a wall with thickness. When you place windows or doors in
that wall, you have to break the lines and do some clean up
to create your openings. If the walls or doors have to be
moved later in the design process, the wall lines have to
be reconnected and a new opening has to be created. With BIM,
you are dealing with objects that are simulations of building
components. These objects know what they are and what their
characteristics are. When you place a wall in BIM, it knows
that it is a wall. It contains information about its materials,
its fire rating and height (just to name a few). When you
place a door object into a wall object, the opening is automatically
created. If you have to move the door, the wall opening is
filled in and an opening is created in the door's new location.
BIM saves money
How often has a design in CAD seemed sound, but when it was
being constructed, problems were determined resulting in costly
changes? With BIM, you are truly developing a model that accurately
reflects what is being constructed in the field. Interference
detection analyses can be run on the model prior to construction,
determining where beams run into each other or where ducts
run into pipes. Wouldn't you rather discover these problems
in the design phase, rather than in the construction phase?
With BIM, this is possible. Besides interference detection,
BIM technology can be used for modeling, drafting, visualizing,
animating, simulating, analyzing and plotting to name a few
of its capabilities. One key aspect of BIM is that it allows
for collaboration amongst engineers and architects on a scale
that has not been possible before.
Do I have to learn something
new?
Right now, you may be thinking, "Oh great! Now I have
to learn something new. Guess all my CAD skills will go to
waste." This couldn't be further from the truth. Throughout
the use of BIM software, like Bentley's TriForma, you are
constantly using tools from the MicroStation set of tools.
Also, after a BIM model is created, extractions are taken
from the model. These extractions are used in creating model
files and sheet files. Once you get to this stage where you
are assembling your construction documents, your CAD skills
are used 100%.
Conclusion
I realize this is only the tip of the iceberg regarding BIM.
Every day, I learn more and more about this exciting and powerful
technology. A year ago, I had heard of BIM, but did not realize
its power. Over this past year, I have been helping the Corp
of Engineers develop a strategic plan for implementing BIM
technology. While CAD is still an excellent tool for design,
BIM technology allows the reuse of information throughout
all phases of a structure's life cycle. BIM also allows for
time and cost savings that could not be realized through CAD
technology. With the current war and disaster recovery efforts
the Corps of Engineers is involved in, money and resources
have become more and more limited. As such, the implementation
of BIM technology is no longer an option for the Corps, but
a necessity.
About the author
Stephen Spangler works as a Mechanical Engineer for the CAD/GIS
Technology Center at the United States Army Engineer Research
and Development Center (ERDC). Mr. Spangler has been heavily
involved with the development of a CADD details library and
AEC CAD standard for the Department of Defense. He is currently
involved in the development of a BIM road map and standard
for the United States Army Corps of Engineers.
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