Rapid prototyping: The next wave in architectural modeling

August 11, 2010

The famous (and hilarious) LIFE magazine photo from 1952 shows a movie theater full of people wearing cardboard glasses enjoying the 3-D experience. Since then, advances in computer tehcnology have made it much easier to view 3-D images. But for many, the need for a tangible model persists, despite the costs and time involved in building one.

Now a technology that has been popular in the manufacturing industry is finding its way into the building design community, and it's quietly revolutionizing what it means to "print" a 3-D design.

Called rapid prototyping, it is a fast, accurate, and efficient process that allows mass and study models to be built in hours or days rather than weeks. The RP machine is essentially a 3-D printer that provides an exact physical representation of 3-D virtual data out of layers of plastic resin. Rather than contracting a model-maker for four to five weeks at a cost of tens of thousands of dollars to create a scale model of a structure using 2-D drawings, design teams and developers can have a hard-copy model created using RP for a fraction of the cost.

RP technology has been used for more than a decade in industrial design. But only a handful of model-making firms specialize in creating rapid prototyping models for architects, developers, and planners.

Laser Graphic Manufacturing of Minturn, Colo., is one such service firm. The architectural model shop caters mostly to the resort architecture market because of its location.

"We got a [rapid prototyping machine] printer about three years ago," says LGM Director Charles Overy. The machine uses a plaster-based material for automated model making.

LGM applies the tool on both architectural and development applications. RP can be used anywhere in the building design phase, but Overy suggests that it's most helpful during early planning stages.

The ability to change CAD data with relative ease, and the speed and accuracy at which the models are built, prove to be invaluable features when design changes are imminent. "It really is part of the digital design process," says Overy.

If an architect or developer has an existing 3-D data set, LGM acts as a service bureau, providing finished, rapid-prototyped parts. LGM works closely with its design clients to ensure that their submitted computer models go directly to the RP printer. For firms that don't work in 3-D, LGM can build 3-D computer models from hand sketches, prints, and CAD data.

Among LGM's current client base is Eagle, Colo.-based architect John G. Martin, who recently used the service for a group of townhomes he designed. Using AutoDesk Architectural Desktop 2004, Martin created a virtual 3-D model of the townhome development and e-mailed the files to LGM.

"We received the data on Tuesday afternoon, and by Wednesday morning he had his model for the design review board," says Overy.

Adds Martin: "For under $1,000, I got back this wonderful model in just a few hours."

Supporting technologies

Service bureaus such as LGM are using other technologies in conjunction with RP to create models, especially on sprawling projects for developers and land planners.

"We do a lot of three-axis milling for large terrain forms (4×8 feet and larger)," says Overy. "We take the [computer model] generated in either 3-D Visual Nature Studio or Form Z and generate cutter paths from that surface data."

The cutters are essentially industrial routers that carve up a block of urethane or polystyrene foam according to programmed instructions. LGM then hand-places the RP building models on the milled terrain form.

Jacobs Engineering, Pasadena, Calif., recently contracted LGM to create several mass model iterations for the firm's Southern Research Institute project in Birmingham, Ala. The model was built using a combination of LGM's in-house RP and milling capabilities with geometry derived directly from Jacobs' 3-D CAD data.

Built at a scale of 1 inch=45 feet, the finished model measured about 48×48 inches. LGM was able to achieve Jacobs' goals of having a model that was cost-effective, adaptive, and easy to understand, all in less than two weeks.

Working with design teams that are disbursed over a large geographic area, Overy points out another use of the technology that can greatly enhance project communication.

"A side benefit we have been seeing is that we can print copies [of a model] inexpensively and send them to design team members who may be distributed throughout the world," says Overy. "Everybody still sees the same physical model."

Printability

One issue with using architectural data on an RP machine is the matter of whether or not the computer model will actually print. Scaling is the biggest problem, and increased complexity can cause the model to fail to print. Walls, for example, become incredibly thin when scaled down.

According to Overy, most RP service bureaus serve industrial design clients, "and very few of these firms know how to work with architectural design firms." Unfortunately, some of these bureaus misleadingly tell designers that they can print data that they actually can't, "which has given the use of RP in architecture a black eye."

Overy explains: "A designer gives the service bureau this great, late-stage [computer] model with all the doors and windows in it on Thursday afternoon, hoping to show the client on Friday. Then he finds out right before the Friday morning meeting that it wouldn't print."

To solve that problem and others like it, LDM is working with major software vendors to develop CADSpan, a polygon mesh resurfacing program that prepares 3-D CAD files for RP printing. The firm currently offers the software as a service, but is planning on selling it next year.

"This software product will make rapid prototyping of architectural data much easier," says Overy.

Looking forward, concept modeling with RP holds great promise in assisting architects, engineers, and construction managers in reducing the design cycle, the same way it has assisted industrial design engineers. Should rooflines not match up or windows be placed inside a column, "another design iteration can be easily and inexpensively created," says Overy.

         
 

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