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by
Glenn W. Birx, AIA
Firm Principal
For
most architects, the purchase of Building Information Modeling (BIM)
software will be just as easy as the purchase of MicroSoft Windows, or
even AutoCAD. When instituting 2D computer drafting back in the ’90s,
architecture firms needed a significant amount of education and training.
However much training it took, though, it was simply a computerized drafting
tool that did not significantly change the way architects practiced—it
just computerized existing practice. BIM, however, in addition to a somewhat
lesser amount of additional education and training, will cause—as
it has caused in my own firm of Ayers/Saint/Gross (ASG)—many cultural
changes that will pervade almost all aspects of practice, from design,
to staffing assignments, to fees, to construction administration services,
and everything in between.
BIM and culture change at ASG
The first step to understanding the difference is to recognize that BIM
is not simply a drafting tool, like 2D computer drafting. It is, more
precisely, a design tool first and foremost, with the added benefit
that it can create a lot of drawings as a byproduct of the design process.
Do not think of BIM as “3D drafting;” if you do, you will miss
its significant, culture-changing benefits. 3D drafting tools have
been improved in recent years to incorporate “parametric object-based
design,” where every object that is used to create a portion
of the model can contain many levels of data about that object. For
example, when a window is inserted into the model, it can immediately
contain information on its dimensions, glass selection, color, hardware,
cost, and even its required schedule for delivery. As such, a BIM database
goes well beyond both drafting and basic object-based design.
But perhaps even more importantly, BIM allows the movement of many man-hours
from drafting to design. Architects can spend more time designing, and
less time drafting. This, of course, in the self-flagellating design
world in which we live, can also be a major problem if we cannot control
our expenditures. But, if managed properly, design can be more thoroughly
studied and completed, as 3D visualization is automatic from the beginning
of concept sketches all the way to construction documents. If managed
properly, construction documents will be better—not perfect, but closer.
The second most important aspect of the culture-changing nature of BIM
as currently implemented at ASG is that the model is a database that
exists in one file, unlike 2D computer drafting, which will have one
file per drawing, or more. This, of course, creates one very large file,
but, we find the fact that it is only one file the key to its distinct
advantage. Think of it as the creation of your building in a digital
form. When we change something in the model, such as the moving of a
wall from one place to another, it changes in all views of the model.
If we change a wall in 2D computer drafting, we must remember to change
the reflected ceiling plan, to modify the dimensions layer, to also move
the wall partition type tag, to adjust the door schedule if there is
a door in the wall, and to change any other details associated with the
wall. Not so with the single file.
A natural first question might be, “How can multiple users work
on one file at the same time?” Our BIM software has a central file
system built into it, allowing building objects to be portioned off so
users can work simultaneously. Depending on the structure of a project
or design team, buildings can be divided hundreds of ways. In some cases,
wings or zones of a building could be grouped together, or the building
can be divided by exterior, interior, roofs, etc. Obviously, since two
users can’t modify the same door or wall at the same time, BIM
software has features that will not allow this. In my practice, this
has not been a problem. We see an increased ability to manage change:
more experienced architects can immediately see changes made by younger
users.
When Ayers/Saint/Gross first contemplated the exploration of this new
software, we were most concerned that as one of the first users, we would
be unable to coordinate with our consultants, owners, and contractors
until they did the same. Our first lesson was to understand that “saving
down” to traditional 2D drafting programs was quick and easy. Once
we satisfied ourselves that this was true and not just a sales tool,
we realized that if it was an experiment that ended in failure, it would
still not be a total loss. Today, almost two years after we began the
experiment, we are still “saving down” in order to coordinate
with consultants.
Implementation of BIM at ASG
In early 2004, our Technology Committee was exploring new technologies
when we first read about BIM technology. We decided that it had enough
promise to warrant a study. We trained two staffers and purchased one
license to use on a small project as a test case. We came up with a
plan to take this project through construction documents, and then
to evaluate its effectiveness after one year.
What actually happened in that one-year period was very different from
our thoughtfully conceived plan. I had a line in my office of architects
begging me to start their new project in BIM. News of this new technology
that dramatically aided the design process and was fun to use had spread
like wildfire throughout the office. I was reluctant at first, but after
one year, we had almost all of our staff of 40 architects trained on
BIM and had decided that all new projects were to be started in BIM.
We have seen dramatic improvements in the quantity and quality of our
visual images, and are beginning to see time savings in many areas. Most
importantly, it was an improvement in staff morale. They love working
in it.
The typical set-up of a BIM database at ASG includes the pre-set development
of traditional drawings, like floor plans and sections.
While working in the model, a tool box can be set up in another portion
of the standard screen so that a simple mouse click will take the user
to a traditional-looking drawing. We do not see not working in traditional
drawing format to be a reason to not make the switch to BIM. It has worked
without a problem at Ayers/Saint/Gross, because it allows drawing development
and coordination in the same way we have been doing it for years. (It
is just a little frustrating knowing that we are not taking full advantage
of the concept yet.)
Cutting sections demonstrates a third and very important characteristic
of virtual building. In BIM, we are not creating drawings, but rather
creating hundreds of views of a digital building. It is incredibly easy
to cut a horizontal, vertical, or even oblique section at any place in
the model to create a building plan. Also, the views of the building
are “bi-directional,” which means that a change made in any
view is automatically made in all views.
Building elevations are created simply by viewing the model’s
exterior. If we want to study our design further, we can move the section
cut this way or that in a few seconds with a couple of mouse clicks.
If a contractor wants to see a section through the wall and not through
a window, we can do so easily.
Advantages and challenges of BIM
In our experience, we have seen many immediate advantages of using BIM.
Some are obvious, but some were a pleasant surprise. Other advantages
will come with time and with more acceptance and usage by consultants
and contractors. But, these are the advantages that we have seen already:
- Better
coordination. Coordination is not nearly as difficult as with 2D
drawings. BIM software can highlight interferences in red, immediately.
- Less man-hours. This translates to less fee-dollars, but, see the paragraph below
about a higher average billing rate.
- Greater productivity. The daily input per
man-hour is of higher quality, so that the output is advanced farther.
- Better
quality design and detailing. More time spent on design and less
time spent on drafting means more time to think design and details
more thoroughly.
- Control
of project information. The BIM database, when used to its fullest
advantage, will become the central source for all project information.
- Opens up new
markets. The database that is the model gives rise to new
services for architects to take advantage of, such as cost estimating,
scheduling, and imaging.
- Educational for young architects. This one was a complete
surprise. Proper input requires the user to understand all of the
parameters of building parts. It forces young architects to find answers
immediately.
Of course, our transition into the BIM world has not been perfect. We
have also found the following to be significant problems:
- “The Bleeding Edge.” Like
any new technology, there is a learning curve, and necessary time must
be spent on training.
- You’re
on your own. Most engineers, contractors, and owners are not
using BIM software yet.
- Software is not yet complete. Some software packages do
not include the full complement of MEP, Structural, and Civil engineering.
- Difficult
to hire trained staff. This is changing rapidly, but currently it
is very difficult to find new employees who have already been trained
on BIM software.
- Professional trainers are novices
themselves. Our power
users quickly exceeded the skills of their professional trainers,
leaving further training to us alone.
- Transition period. There will be a long
transition period within the construction industry, closer to a
decade than a year, before the full advantages of BIM are seen on construction
sites.
Impact of BIM at ASG
Project manpower: The use of BIM
has caused changes in the way we staff a project. We quickly learned
that pure draftsmen are of less value, not having the construction and
design knowledge to build the models, and that young architects who have
more of that knowledge need a lot of guidance. With BIM, gone are the
days of the old design guru sketching on napkins or bumwad and handing
it to draftsmen to be implemented in CAD. The traditional staffing model
might include oversight by a principal, a part-time project manager
and project architect, with a full time architect 1 and a full time intern.
![](1209change4.jpg)
In the new BIM world, we have found that more senior staff input is
required earlier in the project. We have found that our average hourly
rate has increased. But we also find that less total man-hours are required
to do the same job. The daily input of pieces of the BIM model requires
more experience to properly input the parametric data. Our new staffing
model requires about the same level of principal oversight, but both
the project manager’s and project architect’s hours may increase,
while the architect 1 and intern’s hours will likely decrease.
See the example below.
![](1209change5.jpg)
Young architects should not worry about this new model, however. Prior
to BIM, young architects spent much time learning how to become drafters.
This took years of time away from their education as designers. Now,
with the software doing much of the drafting, young architects will continue
that design education immediately upon graduation directly into their
first jobs as an intern. They can look forward to more design assignments
and advancing in their firm as seasoned designers more rapidly.
Fee issues: BIM ultimately will
change the structure of fees, after it has more industry-wide acceptance
and understanding of its effect. Right now, we are still—more or
less—producing our deliverables
in the traditional manner. Ayers/Saint/Gross is not, at this time, planning
on changing our fee structure due to the use of BIM. However, we are
changing how we plan on billing those fees per phase. The traditional
AIA method of billing is 15 percent for schematic design, 20 percent
for design development, and 40 percent for construction documents. Because
of the need for the accurate development of the model during the schematic
design phase, we are seeing the need for a larger portion of the fee.
Our initial thoughts are that we may require 25 percent for SD, 25 percent
for DD, and 25 percent for CDs. Less is required for CDs because if the
model is truly developed at the DD phase, then the CD’s require
less of an effort.
With control of the data, the architect will have other areas, such
as shop drawing production, manufacturing, and scheduling, in which to
have possible fee generation. The value of the model itself may generate
additional fees. The BIM model makes visual imaging much easier, which
can be a fee creator. Some architects are currently charging a monthly
fee for access to the database for all who desire it, such as construction
managers and subcontractors. We don’t see this continuing as a
trend, but it is a good example of a creative way to benefit as the producer
of the database.
Construction documents: Developing
construction documents is much easier when they start with a properly
developed design development BIM virtual building. With the old way,
a good DD set contains “typical” wall
sections and details and “typical” door and window schedules,
for example. With BIM, upon completion of the DD phase, there are no
longer any typical details, as they are already designed into the model.
Additional sections and details are simply cut through the model, and
schedules of doors, windows, and finishes are populated automatically.
This is precisely where the man-hour savings can be achieved with BIM.
We currently debate within the firm “how far to take the model.” The
software has the capability to allow development of all details to a
very fine degree. It can, should we so desire, show all nails and screws
and nuts and bolts. But this is not practical or necessary. Some firms
stop the development of the model at some point and complete the final
level of details in AutoCAD. This practice may make some sense during
the transition period to full BIM construction projects, but it is not
necessary and this final “tuning” of the documents will eventually
no longer be required.
One of the flat-out coolest things we see about BIM software is the “interference
checking.” This is a command that will highlight in red all coordination
problems. It senses when two objects occupy the same space. In the old
way of checking for coordination problems, two or more drawings must
be compared, and combined with an experienced eye to locate potential
conflicts. This method often misses numerous problems, which are then
discovered during construction, leading to cries of “errors and
omissions” and requests for change orders and payment by the architect.
With BIM, press the button and, during design, not even the least experienced
staff member will ignore all the red marks. In the example below, the
red highlights showed a conflicting masonry wall and steel column. It
was corrected immediately and never relied on the QC review to discover.
We haven’t had enough BIM projects go through construction yet
to gather any meaningful data, but we are convinced that there will be
far fewer coordination problems.
Visual images: Starting the design
of a building in 3D on Day One is not only a design advantage, but it
also allows for the constant presentation of the design to our client
in rendering form. The ability to send our model to a rendering engine
to develop movies and fly-through goes a long way toward selling our
design. We have come to learn that this is a blessing and a curse. Our
clients learn that it is relatively easy to request and obtain such views,
so we are receiving many more requests. We are now selling, as additional
services, many renderings, at very low prices for a profit, after an
initial set-up charge for the assets, such as people, cars, trees, site
furniture, etc. The first image below is a view of the BIM model for
one of our projects, and the second image below is the same view of that
model sent to a rendering engine.
Risk management
We can only guess how BIM will affect architect’s liability. The
insurance industry won’t respond until there are documented threats
and court precedents. For now, as we move into the BIM generation, ASG
believes the most important thing is to retain ownership of the documents.
The AIA B141 Owner-Architect Agreement assigns ownership to the architect,
but as you know, many clients and their attorneys insist that they become
the owners of the documents. This may become a deal-breaker in contract
negotiations.
New services
The construction database that is BIM has allowed for the creative development
of new services for ASG. Some examples are as follows:
- Visualization: Renderings
are more easily done in-house and can be sold as additional services.
- Fabrication/shop
drawings. The ultimate use of a BIM model will
be to continue its development all the way through construction. It
is easy to see how the shop drawings for the sheet metal ductwork,
for example, can be completed within the model.
- Code reviews. Some fire departments
and other code officials currently require BIM models for their review
of building projects.
- Forensic analysis. A BIM model
can easily be adapted to graphically illustrate potential failures,
or leaks, or evacuation plans, etc.
- Facilities management. Owners
with facilities management departments greatly appreciate the use
of the model for renovations, space planning, and maintenance.
- Construction
information database The hundreds and hundreds of people and
companies required to supply and build a new building all benefit
from a single source for construction information.
- Cost estimating. BIM software
has built-in cost estimating features. Material quantities are automatically
developed and change with any change to the model.
- Construction sequencing. Ultimately,
with a savvy contractor, the BIM model can effectively be used to create
ordering, fabrication, and delivery schedules for all building materials
and systems.
Virtual modeling for design is not new to the world, only to architects
in the U.S. It has been used by industrial designers, automobile designers,
and aircraft and spacecraft designers for almost 20 years. It is not
that long of a leap from spacecraft to buildings. If a virtual model
of spacecraft can be done prior to fabrication, in order to reduce flaws,
then a model of a building ought to be able to be assembled prior to
construction, for the same reason. With all its advantages to the industry,
a BIM database will quickly become required prior to construction. Architects
are uniquely qualified to be the creator and maintainer of that database,
but are not without challenge in the construction industry. We at ASG
encourage all of you to join us in meeting that challenge.
Copyright 2005 The American Institute of Architects.
All rights reserved. Home Page ![](../../redesign/go_trans.gif)
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If
you have questions about what the AIA is doing about BIM, Integrated
Practice, Interoperability, or other related topics, contact Markku
Allison, AIA, (202) 626-7487 or changeisnow@aia.org.
This article has been prepared and distributed as a service to
our members. The article presents an account of one firm's experience,
and does not reflect AIA endorsement of the software discussed.
On the contrary, the AIA recognizes that there are a range of BIM
solutions on the market and does not endorse any particular package,
nor does it recommend any one package over another. Appropriate
use of the information and opinions contained in this article is
the responsibility of the reader.
ASG’s definition of BIM: Building Information Modeling at
its heart is a database in the visual form of a “virtual
building.” However, it is important to distinguish there
are different varieties of BIM software. The common factor is that
all are object based, but how they allow designers to modify the
database (3D model) is what differentiates between the two basic
types; single directional and bi-directional (better known as “parametric”).
• Single directional BIM software exports information included
in the 3D model to create other views as elevations and sections
or databases like door and finish schedules. Limitations of this
system means changes made in plan (for instance) require re-exporting
to create updated elevations/sections, as well as modifications made
to exported views can not be passed back to the central database.
Traditionally, this type of software uses multiple files to create
the central database.
• Parametric BIM allows a greater fluidity in managing the 3D
model. Because a door shown in plan is the same object shown in elevation
or section, we can modify that door in any view or schedule and have
the change perpetuate through the entire 3D model and all views.
Parametric BIM always has a single central database file. For purposes
of this article, references to BIM should be considered as parametric
BIM.]
File size: While ASG’s use of BIM software creates a large
single file database, the required number of 2D CAD files for each
drawing per project most often added up to a greater size than
a single BIM model. We found that our server was adequate to handle
these requirements. This is an important consideration: A single
central file alleviates the hassles of file management, as one
file versus hundreds is an easy decision.
Interoperability: The International Alliance for Interoperability
(IAI), is developing formatting standards as an IFC (Industry Foundation
Classes) format. Most BIM software manufacturers are cooperating
with the IAI, which means that we need not worry about which software
package will “win” by gaining most industry-wide acceptance.
All of the participating vendors will be able to save to the IFC
format, thus making them compatible with other software. Your decision
on which BIM software package to purchase will likely soon be able
to be made purely on the merits of the software alone.
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