Parametric Modeling Tool Rehabs Design Process

FRAMINGHAM (08/17/2000) - Until recently, like most users of computer-aided design (CAD) software for building design, Scott Brown had to interpret his boss's architectural drawings on trace paper and translate them into a software program that required each design change to be painstakingly replicated in subsequent documents. Ensuring the consistency of all drawings for a large building project was a time-intensive, tedious task with a frightening potential for error.

But Brown and his boss, Joe Frye, owner of Vaught Frye Architects in Fort Collins, Colo., are now using an innovative parametric 3-D modeling tool called Revit, which they said ensures the accuracy of evolving project drawings and allows tighter collaboration with clients and building contractors.

"We are incredibly excited about this tool - it lets us spend much more time designing and much less time drafting," said Brown. "You are actually creating a three-dimensional building on your computer that you can view in any way that you want to view it. I think it can revolutionize the building industry."

Already in use by five of the top 10 architectural firms in the U.S., the Revit parametric building modeler, developed by Revit Technology Corp. in Waltham, Mass., uses object modeling technology to improve the speed, accuracy and efficiency of CAD systems. Revit 2.0, released this month, gives users the ability to make automatic changes in building detailing and massing design while automatically calculating costs.

Revit Technology was founded by veterans of Waltham, Mass.-based Parametric Technology Corp. in 1997.

"The technology that Revit employs represents a significant advance in productivity over the traditional 2-D, drawing-based CAD approach," said Jerry Laiserin, a Woodbury, N.Y.-based fellow of the Washington-based American Institute of Architects, who works as an architect and industry analyst.

"The ability to integrate attributes such as cost is something that has been very difficult for architects and engineers in the past to design to cost," said Laiserin. "We can now take a budget and back-solve the design, which is something that designers could never do before."

Brown, who is an architect in training, said Vaught Frye recently used Revit to design a Boys and Girls Club in Larimer County, Colo. He said Revit allowed the firm's architects to map out the existing school on the site and instantly see the relationship between that structure and the new building.

By inserting a tag for a specific room at the club, Brown said, architects could also immediately calculate square footage for the room and determine the size and cost of the overall building.

According to Brown, floor plans, elevations, building sections, window schedules and room finish schedules are all generated easily from Revit once the initial model is built. Revit allows design changes to be made anywhere by rippling design modifications through the entire documentation set.

Brown noted that while architects like Frye typically avoid CAD systems because of the specialized knowledge needed to operate them, Revit allowed him to immediately create computer-aided designs. According to Brown, it took Frye two hours to create an initial model for the club.

"Those lines he once drew on trace paper are actual walls with Revit, and he can create a block wall 1 foot wide and 25 feet tall, look at the model and call the owner two or three hours later. The time it saves is tremendous," Brown said.

A parametric wall model also presents the wall's relationship to other building components. The software automatically recognizes relationships that capture design intent. These relationships can express setbacks, code requirements and other important client and design constraints.

Error Prevention

Brown said that if he changes the windows on a location, Revit immediately changes the floor plan, as opposed to necessitating that he go back and redraw it. If he wants to change the windows on an elevation drawing, Revit automatically updates the window schedule, which eliminates the potential for errors resulting from drafting inconsistencies.

"It really saves the CAD operator the monotony of just fixing drawings; [before], if you changed a window 6 inches, you had to go back and change the elevation drawings," Brown said.

Brown said he also used the tool to design a medical office complex that included five buildings on a single site. He said he was able to start with a particular square footage and look at the evolution of the complex as he changed the mass of each building.

"You can walk around the whole complex and view the model from all different angles," said Brown.

Brown noted that he's also impressed with Revit's technical support team, which he said can show him how to construct specific design features.

"I can e-mail them my file and they can bring it up on their screen, and I can watch them walk through it, and they send the file back and I haven't lost any time," said Brown. "I haven't talked to a live person at any of the CAD systems that I have worked with."

Revit is sold through a subscription service that allows subscribers to receive upgrades at no additional charge. Revit 2.0 is available to subscribers free of charge, via the Internet or on a CD-ROM. The monthly subscription charge is $199 for a single seat, $175 for two seats or $125 per seat for 500 or more users. Subscription fees also include all maintenance, enhancements, online training and toll-free telephone support.

Reaping the Benefits Of Object Modeling

Larry Rocha, CIO at design firm Wimberly Allison Tong & Goo in Newport Beach, Calif., says his company has been tracking the underlying object technology on which Revit is based since the early 1980s, with an eye toward how it would change the design process itself.

He noted that new modeling tools like Revit require new organizational frameworks and refined methods of communication within the project team itself.

According to Rocha, his firm is still at the early stages of evaluating process changes such as extracting a materials list from an object model that would traditionally be used by contractors to estimate costs.

"In object models, that responsibility may shift to architects, and we are constantly reviewing where are the liabilities and where are the risks," said Rocha. "To truly take advantage of the object model, we have to shift a lot of things in the industry, and the better you can understand those changes and the potential impact of everyone on the team, the better you can take advantage of it."

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