features Pressure Points - A Case Study

Custom programming by Sungrace within SolidWorks automates repetitive design work.

RWDI Case Study

companyAutomation is not just for factories anymore. To build uniformly, machines are programmed to reproduce products; to generate a variety of custom designs, automation is used to speed up the modeling process.

At Ontario-based Rowan Williams Davies & Irwin, Inc. (RWDI), the input is a 3D electronic model, and its output is a series of recommended design wind pressures. The engineering consultancy's recent decision to automate production tasks for pressure studies was similar to how manufacturers invest in more efficient factory machines. Automating modeling tasks within SolidWorks increases efficiency at RWDI by about 15 percent, which in turn increases the company's capacity to perform pressure studies on a monthly basis.

"The real challenge was finding somebody who could understand what we do," says RWDI Wind Engineering Specialist Matthew Browne. "Our work is very specialized – it's not something that everybody does. There's fewer than ten companies in the world that offer these services."

If one is building something big, one will likely need the rarified services of RWDI. As one of the most respected wind engineering firms in the world, it has performed studies on many of the largest architectural projects, from Taipei 101 in Taiwan (the current holder of the Earth's tallest building) and Burj Dubai in the Middle East (which will soon take over the title), to Daniel Libeskind's Freedom Tower at New York's World Trade Center site.

The Pressure Study

RWDI simulates and analyses many of the environmental effects on superstructures using a variety of tools, including wind tunnel testing and computational fluid dynamics. Certain studies, like the wind-tunnel pressure test, require a physical scale model of the proposed building to be constructed, along with the surrounding terrain and cityscape.

"A pressure study looks at the effects of the wind on the exterior envelope of a building in the context of its geographic area. These wind effects will be different in a crowded downtown area than if the structure was built out in the middle of a field. Often times you're dealing with very complex wind flows," explains Browne. "The wind tunnel testing gives very accurate, project-specific design information."

"Once we're retained to conduct a wind tunnel study, we will construct the model, test it, analyze the data, and provide our recommended design wind loads. In most jurisdictions the clients need those recommendations before they can get their permits and proceed with construction."

RWDI constructs its study models using rapid prototyping (RP) technology, or stereolithography (SLA), in which a laser curves a vat of photosensitive resin. The building's surroundings are hand crafted using rigid foam. "The stereolithography process produces very accurate and precise details in our pressure study models." RWDI's Canadian wind tunnel facility performs 30 to 40 wind tunnel pressure tests each month.

With RP, construction of the 1:300 to 1:500 scale models of proposed development is already mostly automated. The painstaking part of the work was performed manually, until recently.

Modelmakers had to drill holes on every surface of the model to install all the pressure sensors, or taps, needed for the wind tunnel test. "Typically, we have to install several hundred pressure taps in a model. The eTAPS project is a way of using our RP technology to also incorporate these pressure tubes in the physical model, rather than doing it by hand with a drill and glue."

The eTAPS, or "electronic taps" project at RWDI sought a way to automate the instrumentation of pressure taps within the software, so the model parts come out of the SLA machine with holes perfectly spaced for testing.

Understanding the process

companyThrough its in-house R&D department, RWDI developed software to locate the placement of pressure taps over a given building model at optimal spacing. To reach into SolidWorks and automatically change the geometry of the actual model, RWDI enlisted the help of Sungrace Software.

Sungrace, whose particular focus is engineering software design and engineering services, specializes in creating the custom tools required by manufacturers, architects, and engineers who want to automate repetitive CAD and modeling tasks. A Manufacturing Network Partner with SolidWorks, a Developer Network partner with Autodesk, and an ANSYS Workbench partner, Sungrace has the programming expertise to improve upon the central applications in design production.

Headquartered in Ann Arbor, Michigan and Pune, India, Sungrace works with a distributed team of software developers and engineers in Canada, U.S., India, and Romania. Just as manufacturing has found global engineering the most cost-efficient, custom programming for modeling automation, too, sees a reason to leverage the wealth of engineering resources worldwide, to make business process improvements a viable option. "We strike a good balance between expert planning and design assistance close to the client and large-scale remote implementation capability to take on massive programming and engineering projects," says Makarand Nalgirkar, President of Sungrace Software.

Given that CAD drawings and 3D models comprise the currency of workflow across several industries, few users may realize the programming flexibility in widely used applications like SolidWorks of AutoCAD. "SolidWorks provides a great deal of functionality in its API that permits geometric analysis and construction of these kinds of complicated features," says Mark Yerry, the senior developer at Sungrace who led the eTAPS project.

"Sungrace came to RWDI with a presentation and proposed an on-site, two-week exploratory phase, during which they would observe our prototyping process," explains Browne. Sungrace then executed the SolidWorks-development stage of eTAPS, completing the bulk of the geometric analysis over the next eight months.

During that time, Yerry and other members of the Sungrace team worked in tandem with the development team at RWDI. "Sungrace would program a new feature, send it to us, and we'd test it out and give them feedback on the performance," says Browne.

Nalgirkar calls Sungrace's method of software development and engineering "Managed Global Delivery™," where programming work, in this case, harnesses global talent while maintaining an intimate knowledge of client requirements.

Poking inside SolidWorkscompany

The SolidWorks portion of eTAPS begins with the import of a XML file. The export from RWDI's program maps the appropriate locations of pressure taps on the building model of the building. Automatically converting this positional coordinates into the solid model features is a conceptually simple task, according to Yerry.

"In many cases, it's straightforward," he says. "A tap will fit and have enough space behind the wall to accommodate the pressure tap. For the ones at the edge of the structure, or where there is a cluster of many in one section, we had to develop a more sophisticated set of tools. The most challenging aspects of this project involved the development of a few key algorithms."

"The most complicated procedure in the SolidWorks add-in is the automatic routing algorithm. Here, the software has to analyze the geometry in the vicinity of the taps to determine a path from the outer surface of the building to a location on an interior wall while avoiding conflicts with other nearby taps."

Some taps would slant upwards or downwards as not to conflict with other sensors. "We programmed the Multi-Point Tap design tool to create the custom paths for the more difficult tap placements. Rather than simple holes, these taps follow a path that the user specifies," says Yerry.

The eTAPS add-on appears as an extra menu inside SolidWorks, which gives RWDI modelmakers the automated means to create the simple pressure taps in the virtual model, the Multi-Point Tap tool for more congested areas and additional tools for mold fixturing. The tools that create more complex paths still require some human decision making inside SolidWorks, but the preparatory time to fully instrument a skyscraper is cut to a tiny fraction of the old drill-and-glue technique.

Cutting time before production

"With the new eTAPS, we are able to cut a significant amount of time out of a typical project," says Browne. The custom automation of production work reduces the waiting time for RWDI clients, the labor costs of professional staff, and allows RWDI to take on a greater number of projects at its wind tunnel facilities in Ontario, Florida, and the UK.

"For deliverables that require customization, but still rely on a sequence of more or less repetitive design steps, automation within modeling software makes a lot of business sense," says Nalgirkar. "For a lot of companies, 3D models are the final deliverable, rather than a physical product. For the amount of time spent processing and manipulating 3D data, there's no reason not to apply automation to save steps in the process."

The eTAPS SolidWorks add-on is proprietary and not for sale, and given the highly specialized work of RWDI, few others would need it. As firms involved in 3D manufacturing and architecture look for new ways to improve efficiencies, many may soon acquire with RWDI now has: a SolidWorks modeler of their very own.

About RWDI

Established in 1972, Rowan Williams Davies & Irwin Inc. (RWDI) is recognized internationally as a leading specialty consulting engineering firm. This unique company with over 300 employees has established a worldwide clientele that seeks its expertise for solving architectural, engineering and industrial/environmental technical problems. RWDI is the leading wind engineering consulting services firm in the world. The company offers a complete range of wind engineering, environmental air quality and noise management services. The firm's key clients include leading architectural, mechanical and structural engineering firms, plus private and public facility owners. RWDI also offers advanced air quality, noise and hazard/risk modeling, monitoring, and measurement expertise to industry and government clients. For more information, please visit: www.rwdi.com.

About Sungrace

Sungrace is an R&D partner to leading software and manufacturing Original Equipment Manufacturers (OEMs), Engineering Procurement & Construction (EPC) companies and their software and design-engineering suppliers. Sungrace provides Managed Global Delivery™ of technology-enabled services including engineering software development, design automation, 3D design, CFD and FEA.