| It has been over
twenty years since I began using CAD to produce my designs and
construction drawings. The first CAD computer I used cost about
$100,000, and did not have even one percent of the capability
that my computers have now.
But for it’s time, it was an advanced computer
that ten years earlier existed only in our imaginations. In
fact, ten years earlier I used a CAD computer that was being
developed at the University of Illinois. It took a foot-high
stack of key punch cards to draw a rectangle (I’m exaggerating,
but just a little), and one wrong key punch or one card out
of order, and it didn’t work at all.
Now architects and the building industry as
a whole are facing the next great leap in technology.
Most people, when they hear the acronym CAD,
know that it means computer-aided drafting. The next acronym
for us to learn is BIM, or Building Information Modeling.
We currently have the capability of drawing
an entire building in three dimensions with our standard CAD
computer software. However, the objects that we draw in CAD
are just that, lifeless objects.
BIM takes 3D drawings to the next level by making
these objects intelligent and able to interact with other objects.
For example, let’s say that I have designed
a building in three dimensions with CAD. It includes the foundation,
the walls, doors, windows, ducts, lights, ceilings, and all
of the components that make up the building.
To revise the 3D model of the building in CAD,
you make the changes just like you would if you were to have
constructed the model with wood and cardboard. You disassemble
the model, trim and re-shape the parts and pieces, and re-fit
them all together again.
With BIM, objects can be intelligently interlocked
together, so if I had drawn the same building using BIM, the
changes could theoretically be made without disassembling the
model.
With two dimensional CAD, we can “stretch” items,
making them larger or smaller. With BIM, you could do a similar
thing. As just one example, you could stretch the length of
the building, and the system would automatically revise the
length and diameter of air conditioning ducts, revise the size
of the air conditioning system, and re-calculate the heat loss
calculations of the building envelope. It might also reduce
the number of light fixtures, change the pattern of fixtures
to achieve a certain level of lighting, and alter the number
of electrical circuits that are required to light them. At the
same time, it would re-design the foundation, the floor joists
and the roof structure.
There are some distinct advantages to using
BIM technology. It could make fine-tuning a design to meet project
criteria much easier, and it can be used throughout the life-cycle
of the building for maintenance and operational purposes.
This all sounds like it might make the architect’s
job much easier, but in reality it won’t. In fact, in addition
to all of the work that the architect traditionally does, the
architect would also have to become a facilitator to integrate
all of the intelligence that goes into the building, by coordinating
and programming all of the components that goes into it. This
also means that the other design professionals, such as the
structural, mechanical and electrical engineers, must be able
to communicate their designs to the architect in a way that
the architect can integrate them into the BIM files. Manufacturers
of building products would also have to supply BIM files for
their products that the architect could insert in the BIM files.
Obviously, BIM is probably a very long way from
being as widely used as CAD is now. At present, the vast majority
of architects and engineers don’t have the capability of using
it, nor do manufacturers.
But it is coming, and it is being forced into
use by the federal government. The General Services Administration’s
Project Knowledge Center will require firms who provide design
services to the GSA to include a Building Information Model
beginning in the 2006 fiscal year.
BIM will dramatically change the way architects
provide services to their clients over the coming years. The
change from drafting on paper with pencils to using CAD was
a relatively easy one compared to making the transition from
CAD to BIM. However, once made, our buildings will have a much
higher quality than ever before.
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