Brave New BIM28 Aug, 2008 By: Pete Zyskowski
Transitioning to building information modeling requires much more than a change in software.
By now, most everyone in the AEC industry has heard about building information modeling, or BIM. However, some confusion persists about the concept and its practical applications. This article aims to shed some light on BIM and prepare you to take the first steps toward implementation.
The concept of BIM actually has roots in other industries, primarily manufacturing and industrial design. The need to control information and grow it through iterative design processes -- all the way to the manufacture of the item -- was recognized by these industries years ago. What came out of this need were programs designed to parametrically control, modify, and test manufactured pieces before they were even produced, a practice known as digital prototyping. This idea fit well into manufacturing because the items being created are mass produced and therefore no longer one-off designs. The time spent modeling and testing digitally was, and still is, more cost-effective than manual modeling and absorbs just a fraction of the overall profit to be earned by making thousands of the item in question.
BIM is this same concept but on a much grander scale. When the idea of digital prototyping originally moved into the AEC community, the same needs were recognized but were still out of reach because of several factors.
First, the scale of what was needed to be modeled was out of the realm of the existing programs. No existing tools could efficiently model buildings (which are unique designs each time) nor was there an ability to recover the cost of modeling the building through mass production. Additionally, even if you could model an entire building, affordable computers at the time weren't powerful enough to run the program. So the AEC industry fell short of actual implementation, although the ideas were still there hovering in the ether.
Moving Into BIM
The roots of BIM are generally accredited to Graphisoft, with its release of ArchiCAD. Development on ArchiCAD began in 1982, with the first truly viable release in 1987 with version 3.1. Since then, several other programs have come into the market, with Autodesk Revit emerging as the industry leader.
These programs allow the architect the flexibility to create walls, floors, roofs, and other architectural elements in 3D to define shape and space, see the results of changing dimensions, and even see how modifying the assembly will change the outcome of the building design -- all in one file, from basement to roof.
Interestingly, other objects such as doors and windows, which still lie in the realm of the manufacturing industry, can be downloaded from digital libraries or catalogs and inserted into the architectural models. Thus the architect is now not only a designer but also an assembler, linking virtual pieces and parts to their manufacturers through the building specifications.
That being said, the first thing a firm needs to know when looking to move to a BIM platform is that its workflow will change. It may take a project or two to realize how dramatic this change might be. Much of this is determined by the specific types of projects the firm handles. The change in workflow comes from the way the designers are now able to interactively and parametrically alter the design of the building, and the fact that more information is inherently added to the design process in the early stages.
Traditionally, architects have used the centuries-old method of plan and elevation design, accompanied by a physical model of the building, to explain building details to the client. Even CAD programs were just an extension of this traditional methodology, replacing pen and paper with digital drafting tools. But after all the sketches and planning, a CAD program is still just a documentation tool. Sketches are still going to be necessary.
However, BIM allows the designer to actually see the consequences of a design decision immediately and in three dimensions. Essentially, a BIM program is a design tool in which documentation is a derivative of the design process, not a process unto itself. This gives many BIM programs a less technical feel than the hard-lined, multicolored, and cross hair-oriented drafting programs, even though all the tools are still there.
With BIM, the need for more 3D information typically comes much earlier in the process. For instance: Not only is this a wall, but what type of wall? This window needs to be sized and placed properly. Who is the manufacturer? What type of construction is being used? What type of HVAC? If this information can be acquired, the project will run much more smoothly overall.
Accordingly, most firms are recognizing the need to restructure their billing schedules with BIM, with more time being billed earlier in the design process and tapering off through construction documentation. Firms also have recognized the need to bring in consultants and contractors earlier in the design process to get the needed information. Integrated project delivery (IPD) is the term being used for this new process of forming a full design team.
Many BIM programs are able to track callouts and sheet numbers, eliminating the routine and tedious task of tracking changes through the building and the sheets. This allows the design team to focus on the real issues of modifying the building design. Some firms have reported being 75% complete with a project before even issuing the design development package because of the ability to make informed design decisions and having the information up front. Obviously, in these cases, change has been worth the effort.
Another core component required for BIM is increased horsepower: 3D, parametric design is computer resource intensive. The workstations that most firms are currently using may not be enough. Though the BIM software itself is fairly efficient, displaying an entire model at once is a demanding prospect.
In contrast, drafting applications essentially pancake the building into floor plates, which lets you look at one floor at a time, resulting in smaller files. Take a look at the CAD folder in your project and you will be astonished to see just how large the cumulative file size is for an entire building. The BIM model will more than likely be smaller than that, but you will still be looking at a large single file, all at once. For this reason, you will need a workstation with dual processors, an ample amount of RAM, and a robust graphics card. This is, unfortunately, a hidden cost of transitioning to BIM.
However, firms that refuse to update their workstations, or at least their graphics cards, tend to get frustrated with the poor response of the model and will not want to pursue the program further. The return on investment of a good workstation is amazing in terms of both time and frustration saved.
Choosing the Right Reseller Partner
Once a firm has decided to move to a BIM platform and the budgets have been set for newer, more powerful workstations, quality training and guidance should not be overlooked. Yes, this is another cost, but if a firm is committed to getting a maximum return on investment from the new program, then its team must be able to use it effectively.
A good reseller or consultant will be able and willing to partner with you not only to figure out what you need to buy in the workstation department, but also to teach your team members how to implement and adapt to BIM practices. This education should not be only about the BIM program but how the entire firm will use it effectively. Knowing that your workflow will change is one thing, but having someone to consult and to help you chart your new workflow and choose a good pilot project is important. A quality reseller should be able to customize training to ensure the best results from your BIM investment.
As stated earlier, project type can have a vast impact on how the BIM application is used. Commitment is key here, from the firm itself and its pilot team, as well as the strategic reseller partner.
Teaching and mentoring will most likely continue through the entire pilot project. You will also need to figure out how your CAD, quality assurance, and office standards will be affected.
Brave New BIM
The world of BIM is ever evolving, and it is best to take baby steps into it. Your first project most likely will be focused on trying to replicate the look and feel of your firm's construction documents. Subsequent projects should allow you to start working with BIM-based partners and consultants such as structural and mechanical engineers, both of whom bring their own subtle preferences to the table about how the model should be approached and shared.
As you move forward, you will be able to investigate other, more advantageous opportunities presented by BIM. BIM plug-ins and add-on applications are available that will allow you to analyze the building for thermal and mechanical efficiency, LEED credits, specifications, egress, and even code compliance. Add these tools one or two at a time and let your teams learn them before moving to the next level.
I hope this overview has provided an idea of some of the hurdles, hidden costs, and changes that come with the transition to BIM. There is one final thing to mention, and even though it comes at the end of the article, it is really the foremost issue that you need to think about: Why do you believe you should move to a BIM platform? Identify your needs and set your goals and expectations, but be realistic and redefine these ideals as you move from project to project. A good goal is one you can realistically achieve. If you are looking for a productivity boost, how are you going to define the goal and how will you evaluate the numbers to see if it was met? If you fall short of your goal, was it because the goal was unrealistic, or was there a problem with the planning or training?
Above all, realize why you are making the change. Understand the process changes, time, and effort that lie ahead for your firm, and bravely step into the new world of BIM.
Autodesk Technical Evangelist Lynn Allen guides you through a different AutoCAD feature in every edition of her popular "Circles and Lines" tutorial series. For even more AutoCAD how-to, check out Lynn's quick tips in the Cadalyst Video Gallery. Subscribe to Cadalyst's free Tips & Tools Weekly e-newsletter and we'll notify you every time a new video tip is published. All exclusively from Cadalyst!