In Pursuit of the Perfect CAD

Design software for engineered building systems is—and always will be—in a state of becoming. Every new software enhancement is greeted with a demand for even more upgrades. This month's panel discusses the kinds of design software capabilities that engineers are looking for. CONSULTING-SPECIFYING ENGINEER (CSE): Some consulting engineers have expressed to us disappointment in the ...


Design software for engineered building systems is—and always will be—in a state of becoming. Every new software enhancement is greeted with a demand for even more upgrades. This month's panel discusses the kinds of design software capabilities that engineers are looking for.

CONSULTING-SPECIFYING ENGINEER (CSE): Some consulting engineers have expressed to us disappointment in the progress of CAD developments. They seem to feel that currently available design software isn't yet meeting their needs. So, what specific capabilities are M/E/P engineers looking for in computerized design tools?

DEFEO: Many of the capabilities that our engineers are looking for are already available within existing CAD software. The problem is that most applications lack the tools to perform certain functions with the CAD file data. For instance, there are no tools to perform calculations or to create an automated schedule or generate specifications. These reports or outputs of the intelligent data have to be generated outside the program with some other application.

KRAWCZYNSKI: Engineers are looking for tools that reduce production time and increase accuracy. For example, since many M/E/P engineers are consultants to architects, there is a need for the software to interact with that of the lead firm with minimum transition time.

In the past, many of the advances in CAD software packages were mostly directed to the construction portion of the project, and to a much lesser extent, the design engineers. A review of the design process would highlight the fact that when an engineer receives an architectural floor plan to use as a base for the mechanical and electrical systems, it contains many entities—dimension strings, notes and door numbers—that are not required on the M/E side. But these items use memory and slow screen regeneration speed.

If architectural plans were produced with layering that would efficiently allow purging of non-essential information for engineering plans, this would greatly reduce production time. Of course, this is only valid where the architect and engineer are using the same program.

Engineers are also looking to the CAD program to be more than a drafting tool. Capabilities could include simple coordination of reflected ceiling plans for locating conflicts, and easy creation of equipment schedules based on input equipment. This does not mean a schedule of quantity.

THEIN: Our company [Bentley] has identified four areas where engineers would like to see further development. First, they want tools that facilitate collaboration with architects and structural engineers: i.e., to reference their data for design coordination. Second, they are looking to design M/E/P systems in single- or double-line 2D, or directly in 3D. Third, they want the software to generate construction documentation, such as drawings and quantity takeoff reports. Finally, engineers want links to analysis software—for heat loss/gain, electrical loads and cooling loads, as well as pipe, duct and cable sizing—and performance simulation applications for lighting levels, glare, temperature predictions and the like.

CSE: What other new CAD capabilities are software developers coming up with to satisfy these needs?

DEFEO: One other new development is increased calculation abilities, such as cost estimation. Also, the products are also becoming easier to use, shortening the learning curve.

Developers also continue to increase the 3D capabilities of CAD for building engineering. This development is ongoing, and with the input of engineers, the software is more data driven, allowing for easier sharing of information.

THEIN: CAD software is always getting smarter. In [Bentley's] HVAC for MicroStation TriForma, for instance, mechanical engineers can work in single- or double-line representation and have a 3D model generated, either simultaneously or as a post-process.

In fact, duct routing can be done directly in 3D. Fittings such as elbows, Ts, Ys and reducers are placed automatically, based on user-defined defaults, but can be swapped out at any time afterwards.

Another timesaver is the automatic hookup function that connects devices such as diffusers to either rigid or flexible ducts or a combination of both. In our system, an object created with our other applications can be queried for type, material or quantity—an example of cross-discipline integration.

KRAWCZYNSKI: Our office is presently using AutoCAD ADT 3.3. We selected this version based on our review of beta versions of Autodesk's new Building Mechanical and Building Electrical products. These products serve the needs of the M/E/P design engineer with capabilities such as switching between single- and two-line ductwork; drawing fittings automatically to current standards; creating equipment schedules; creating schedules of electrical loads on each circuit; and creating circuit reports indicating devices and electrical loads.

Sharing design data

CSE: Earlier, we touched on interoperability and cross-platform compatibility as continuing issues for software developers and users. What kind of progress has occurred on this front?

DEFEO: The ability to share data from an intelligent CAD file is a big advantage. Although some applications are not compatible, one will more than likely be able to extract data from a CAD database and use that information within another application for cost estimation or calculations.

THEIN: At Bentley, for example, all of our V8-generation applications allow referencing of DWG files containing 2D and 3D data without translation, thus providing about 70% compatibility of all data formats—mainly DGN and DWG—used on AEC projects.

Also, we provide technology that allows data from a number of discipline-specific applications—for instance, structural, HVAC and piping—to be checked for clashes of objects of the same or any other discipline. And objects can be linked to events in project management and scheduling applications in order to simulate the progress of construction on-screen.

KRAWCZYNSKI: MicroStation can open AutoDesk's DWG format files and save as DWG files. But our understanding is that AutoDesk cannot automatically open or save in MicroStation format. This has not been a concern in our office in recent years because all of our clients are presently using AutoDesk's AutoCAD software package.

CSE: It safe to say that the M/E engineers' wish list also includes capabilities that foster collaboration and communication. For example, HVAC and controls engineers want to work from the same, or at least compatible, drawings files. How far has CAD developed in this respect?

THEIN: We are heavily involved at the board level in several local chapters of the International Alliance for Interoperability [ ]. The objective is the development of industry foundation classes (IFCs), a standard format for the exchange of intelligent objects across application and data format boundaries. Currently, IFC 2x is being defined and Bentley is committed to its implementation in their products.

DEFEO: Most CAD software is compatible through conversion to another software. Over the years, the tools to perform these conversions have been enhanced. Collaboration by an integrated project team will always flow better when everyone is working with the same software. Recently, there has been a new release by one major CAD vendor that claims to be able to open, without conversion, another CAD file type. This could prove very helpful for integrated project teams that use different CAD software. If file type becomes a non-issue in the future, it would be good for everyone.

KRAWCZYNSKI: Again, our experience has been that many consultants, contractors and supplies are using AutoCAD. Sometimes, another version of AutoCAD is used by the vendor, but even then, AutoCAD has the ability to save down to previous versions. The main obstacle for us is not so much a collaboration issue as a contractual issue. As part of the general conditions of the project specifications, a section has been added to address contractor and vendor use of the CAD-generated information and limitations of liability.

In fact, we do provide AutoCAD drawing backgrounds and M/E/P plans to consultants, contractors and vendors based on the general conditions of the contract.

Leveraging the Internet

CSE: The Internet seems to have had a major impact on the use of CAD design tools. How has the use of CAD on project management web sites affected CAD software development? Has it led to new and innovative software features and capabilities?

DEFEO: I feel that this relationship is the other way around. As CAD capabilities increase and improve, the web sites that house these projects will have to provide new and innovative tools to work with the increased capabilities of these CAD tools.

There has been progress in the ability to download symbols or objects directly from a vendor's web site onto a CAD drawing. As this function develops, it may prove to be a time saver for both 2D and 3D CAD.

KRAWCZYNSKI: One development we have seen is that the major equipment manufacturers provide access to equipment symbol libraries, some with CAD-ready drawings that can be incorporated into engineering drawings via the Internet.

AutoCAD 2002 allows uploading and access to CAD drawings located on a project management/collaboration web site. During the past year, we have participated in projects that utilize a project management web site during the construction phase. We have a project scheduled to begin in June of 2002 that will be used during the design phase of the project.

THEIN: The Internet has provided Bentley with opportunities to develop applications such as Viecon and Model Streaming that leverage the Internet for project collaboration. Also, several server-based applications, such as ProjectWise and ActiveAssets, include technology to access data via web browsers.

CSE: With respect to applications for the M/E design community, what are the big challenges for CAD developers in the future?

KRAWCZYNSKI: The big challenge is to provide the latest application tools without sacrificing software program efficiency. New programs are becoming more complex, placing greater demands on the hardware and thereby increasing overall operational costs. As the programs become more complex and design tools are integrated into the CAD programs, ease of use and sufficient training tools need to be incorporated into the product. Proper training materials will ensure optimal use of the program's features and capabilities.

THEIN: I agree. Today's technology allows development of sophisticated and complex applications. The challenge for developers is to make such programs so easy to use that engineers actually use them and can fully exploit their power and scope. Usability labs are one way of getting feedback for the design of an effective graphical user interface, but developers also need to create self-teaching tools—on-line tutorials—good product documentation and proper training-class material that teach engineers not just how product features work, but how they solve engineering problems.

DEFEO: I would like to see them create an all-inclusive software that accomplishes all of an engineer's needs—HVAC, piping, electrical, etc. This is a difficult challenge for CAD developers because every engineer's needs are different. Presently, you still need to get an HVAC application somewhere and a piping application from somewhere else, and the applications generally have different levels of capabilities. This is basically the standard for all applications. If a developer could put together a comprehensive suite of engineering applications that includes integrated interference checking, cost reporting and reasonable calculation capabilities—all of which are open ended for customization—it would prove to be very successful.

M/E Roundtable Participants

Robert Defeo, manager of CAD operations, Kling Lindquist, Philadelphia.

Steve S. Krawczynski, P.E., vice president, vanZelm Heywood & Shadford Inc., West Hartford, Conn.

Volker Thein, director of industry marketing international, architecture & construction, Bentley International, Hoofddorp, The Netherlands.

Interfacing with CAD

As computer-aided design software continues to develop, so does its ability to interface with other types of applications. In particular, design professionals have been interested in the ability to capture design data and pass it on to project management and cost estimating systems.

"CAD software continues to become more intelligent," says Robert Defeo, manager of CAD operations at Kling Lindquist, Philadelphia. "The intelligence from a CAD drawing is normally stored in a database, which can then be accessed by many other computer applications. For example, the appropriate data could be extracted from the database into a cost program."

Defeo suggests that other types of data could be extracted from CAD databases to perform a variety of calculations. "Once a CAD object has intelligence and that intelligence is stored in a database, the options for sharing that data with other applications increases dramatically," he says.

Bentley Systems has registered that message. For example, the company has expanded the concept of the "single-building model" to an "integrated-project model" with a comprehensive portfolio of products and services. "This provides an integrated environment to create, manage and publish all engineering content as well as project information for the entire life cycle of buildings," explains Volker Thein, international marketing director at Bentley. "This includes design, engineering, document management, analyses, clash detection, schedule simulation, construction, facilities management and more."

Beyond CAD

Computer-aided design is not the only kind of software design tool used by the designers of engineered building systems. There have been many recent upgrades and innovations in energy analysis and systems modeling software as well.

"Performance simulation software is increasingly gaining importance and attention, not just from architects and engineers, but also from building owners as the ultimate beneficiaries," says Volker Thein, international marketing director at Bentley Systems. "For instance, predictions of light levels, solar gain and ventilation patterns across an entire year allow optimization of systems that minimize the use of energy."

In addition to modeling and performance-simulation applications, load calculation is an important tool in the engineer's software tool box. "The HVAC load calculation program now has the ability to use AutoCAD-generated drawings as backgrounds to prepare area takeoffs," adds Steve Krawczynski, P.E., vice president, vanZelm Heywood & Shadford, West Hartford, Conn.

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