AutoCAD

If You Can Dream It, They Can Build It

17 Feb, 2011 By: David Cohn

Dynamic Structures uses AutoCAD to design really cool stuff — from telescopes to theme-park rides.


Editor's note: Through a sponsorship by Autodesk, Cadalyst editors bring you this feature, part of a special series of articles that highlight the role of AutoCAD and 2D design in today's demanding CAD work flows. Watch for the next installment in March.

Some of the coolest things in the world are designed using AutoCAD. Like what? How about the world's largest telescope, virtually every major theme-park ride built in the past 20 years, the ski jumps for the 2010 Winter Olympics, and an award-winning pedestrian bridge shaped like a DNA molecule. And what do all these projects have in common besides AutoCAD? They were all the work of Dynamic Structures, an 85-year old company based in a suburb of Vancouver, British Columbia, that has developed an international reputation for its extensive experience in the design, fabrication, and construction of elaborate steel structures.

Founded in 1926 as a manufacturer of wrought iron and subsequently merging with an even older company that made horseshoes, Dynamic Structures began building telescopes in the 1970s. Its first telescope enclosure, for the Canada France Hawaii Telescope, was the first to be built at the 14,000-foot summit of Mauna Kea in Hawaii. Since then, the company has provided detailed designs, manufacturing, and on-site construction of enclosures and telescopes ranging from 3.5 meters to 10 meters. Projects have included Keck I and II on Mauna Kea (currently the largest ground-based telescopes in the world), the twin Gemini Observatories in Hawaii and Chile, and the William Herschel and Isaac Newton telescopes at the Roque de los Muchachos Observatory in the Canary Islands.

The enclosure for the William Herschel Telescope presented Dynamic Structures with numerous challenges, including remote-site construction on the island of La Palma in the Canary Islands. (Image courtesy of Dynamic Structures.)
The enclosure for the William Herschel Telescope presented Dynamic Structures with numerous challenges, including remote-site construction on the island of La Palma in the Canary Islands. (Image courtesy of Dynamic Structures.)
 

From the Stars to Fantasy Lands

When the Keck telescope project manager left that job and went to work at a major theme park, he approached Dynamic Structures and asked if the company would be interested in building a new ride that was under development. The answer was yes.

Dynamic Structures' senior designer Craig Breckenridge remembered that day very well. "We started to look at this ride and told them that they needed to take fatigue into account. And they honestly hadn't thought about it. Nobody had," he recalled. Until then, parks simply took a brute force approach, overdesigning every component. That ride became the first ever to take fatigue into account, and Dynamic Structures quickly established itself at the forefront of the multibillion dollar international amusement ride industry, designing, manufacturing, and assembling the ride's complex structural and mechanical systems.

Dynamic Structures built its first theme-park ride in 1997, modeling all of the track sections in 3D using AutoCAD. (Image courtesy of Dynamic Structures.)
Dynamic Structures built its first theme-park ride in 1997, modeling all of the track sections in 3D using AutoCAD. (Image courtesy of Dynamic Structures.)
 

Today, the company typically works on designing or building something astronomy-related while simultaneously developing several theme-park projects. But Breckenridge notes, "A telescope generally takes 7 to 12 years," while a ride is typically completed in two. Today, the major theme-park operators as well as other amusement parks come to Dynamic Structures on a regular basis.

"A client will come to us with a ride that they want to build," said Breckenridge. They may have a theme in mind or just want a ride to fit into a specified space. "Sometimes they have a bare room and ask what they can fit in there. Other times, they have an existing ride that we're going to refurbish."

What happens next depends largely on how much money the park is willing to spend. "We can't give them much for $5 million. If they've got $50 million, you can get a pretty cool ride." The most expensive ride Dynamic Structures has built to date cost close to $100 million and has broken attendance records since it opened in June 2010. (Confidentiality requirements limit identifying specific projects.)

The first step is to determine what type of ride to build: a RoboCoaster, in which articulated robot arms mounted to the ride vehicle lift, rotate, and tilt passengers as the vehicles move along coaster tracks; a motion theater in which seats pitch and heave while audiences watch movies on a large screen; or a trackless ride using automatically guided vehicles (AGVs). Dynamic Structures specializes in all three types. Regardless of which the customer chooses, the next step begins with AutoCAD.

Dynamic Structures' latest RoboCoaster uses programmable robot units mounted to ride vehicles. The robots lift, rotate, and tilt passengers as the vehicles move along coaster tracks. (Image courtesy of Dynamic Structures.)
Dynamic Structures' latest RoboCoaster uses programmable robot units mounted to ride vehicles. The robots lift, rotate, and tilt passengers as the vehicles move along coaster tracks. (Image courtesy of Dynamic Structures.)
 

It All Starts in AutoCAD

Dynamic Structures' engineers begin by creating concept drawings and coming up with ideas that meet the client's demands and are buildable. If it's a coaster, the next step is to lay out a track's centerline in AutoCAD. From there, some components — particularly those that move, such as the ride vehicle or track switches — will be modeled in Autodesk Inventor. In many situations, the AutoCAD and Inventor models will be brought into Autodesk 3ds Max or Autodesk Maya to create animated simulations that clients can view as a proof of concept.

At some point, the fabrication staff will become involved to figure out practical methods of building the ride. The drafting staff will begin work on the actual fabrication drawings. Components such as track sections are manufactured on site from steel cut by machines that run directly from DXF files exported from AutoCAD. Intricate, machined parts are produced by outside suppliers. But in most instances, the suppliers' computer numerical control (CNC) machines are programmed directly from AutoCAD and Inventor files created and provided by Dynamic Structures.

Parts are cut directly from AutoCAD models and components such as track sections are manufactured in the fabrication shop at Dynamic Structures' headquarters near Vancouver, British Columbia. (Images courtesy of Dynamic Structures.)
Parts are cut directly from AutoCAD models and components such as track sections are manufactured in the fabrication shop at Dynamic Structures' headquarters near Vancouver, British Columbia. (Images courtesy of Dynamic Structures.)
 

The company likes the cross-platform compatibility of the Autodesk software products. Breckenridge noted that engineers can model a part or assembly just once and then bring it into any of the Autodesk products. When projects involve models from vendors who use other software products, Dynamic Structures uses Autodesk Navisworks to bring everything together. The company also uses Vault to keep track of the CAD files as well as the thousands of other documents generated throughout the course of a typical project.

Much of the initial design work involves laying out geometry and figuring out what will work. Breckenridge has found that this often is easier to do in AutoCAD, because he can draw and erase objects easily, whereas in Inventor, he must first create a sketch and then extrude it into a solid. "In a 40-foot section of track, there are probably 300 parts," said Breckenridge. "We've got sections of track in Inventor, but we don't have the whole track in Inventor."

Dynamic Structures uses AutoCAD to lay out the track centerline for a roller coaster and then develops complete models using either AutoCAD or Autodesk Inventor. Cross-platform compatibility means the engineers can move easily between various Autodesk products. (Images courtesy of Dynamic Structures.)
Dynamic Structures uses AutoCAD to lay out the track centerline for a roller coaster and then develops complete models using either AutoCAD or Autodesk Inventor. Cross-platform compatibility means the engineers can move easily between various Autodesk products. (Images courtesy of Dynamic Structures.)
 

Spreadsheets Drive CAD

Dynamic Structures began using AutoCAD with release 9, and did its first 3D modeling in release 12. "By the time we were in release 14," noted Breckenridge, "we were doing a lot of 3D modeling. The telescope enclosures lend themselves to some pretty complicated 3D models right away to make sure that we understand how connections work."

"We can do two million solids in AutoCAD, no problem." said Breckenridge. Dynamic Structures' engineers can model the entire structure in AutoCAD using dummy solids that don't have any materials associated with them, then quickly manipulate the model in 3D.

But the engineers don't just start drawing in 3D. Although they can create helical curves in AutoCAD — "if you get the math right" — they start instead with a Microsoft Excel spreadsheet. "There's a pattern to it," said Breckenridge. "It doesn't matter whether you're doing a ride or a telescope. There's always a pattern to the geometry." After defining those patterns and using subroutines in Excel to define the track centerline coordinates mathematically, the spreadsheet automatically draws lines or curves between those points in AutoCAD, then extrudes shapes along those paths.

The engineers also can use the same spreadsheet to create models in Inventor or in ANSYS, which the company uses to calculate the structural loading on the track. With numerous PhDs on staff, Dynamic Structures has customized its ANSYS software and written its own custom software. In the past, the company used Adams from MSC Software for mechanical simulation, but it now is moving toward Autodesk's Algor simulation software.

Testing, Testing

At Dynamic Structures, unique engineering solutions are the norm, so testing is critical to the development process. Today, the company depends primarily on digital prototyping using Autodesk Inventor, wherein users rely on the software to provide feedback about design accuracy, integrity, and suitability for manufacturing. Digital prototyping can eliminate the need for many, if not most, physical prototypes.

For the Olympic ski jumps, Dynamic Structures faced the challenge of building 95- and 125-meter long trusses, each 8 meters wide and 4 meters high. Not only did the trusses have to meet similar tolerances, they also had to be transported to a remote mountainside and assembled in time for several international events held two full years before the opening of the 2010 Vancouver Olympic Games. Dynamic Structure's comprehensive design process ensures this level of accuracy.

Dynamic Structures was responsible for detailing, fabricating, and erecting the steel superstructure of a unique helix-shaped pedestrian overpass in Seattle for the world's largest biotechnology company, Amgen. (Image courtesy of Dynamic Structures.)
Dynamic Structures was responsible for detailing, fabricating, and erecting the steel superstructure of a unique helix-shaped pedestrian overpass in Seattle for the world's largest biotechnology company, Amgen. (Image courtesy of Dynamic Structures.)


For the Olympic ski jumps, Dynamic Structures faced the challenge of building 95- and 125-meter long trusses, each 8 meters wide and 4 meters high. Not only did the trusses have to meet similar tolerances, they also had to be transported to a remote mountainside and assembled in time for several international events held two full years before the opening of the 2010 Vancouver Olympic Games. Dynamic Structure's comprehensive design process ensures this level of accuracy.

The massive trusses for the 95- and 125-meter ski jumps for the 2010 Winter Olympics were shipped first using wide-berth barges and specially built vehicles before being assembled on the side of a mountain. (Image courtesy of Dynamic Structures.) The massive trusses for the 95- and 125-meter ski jumps for the 2010 Winter Olympics were shipped first using wide-berth barges and specially built vehicles before being assembled on the side of a mountain. (Image courtesy of Dynamic Structures.)
 

Before digital prototyping came on the scene, the company built full-size prototypes of complex structures and even assembled parts of rides on its 10-acre lot to ensure that components would fit together properly when delivered to the site. The entire Atacama Cosmology Telescope was assembled at the Dynamic Structures plant and put through a series of tests to ensure it met specifications before being shipped to Cerro Toco mountain in Chile.

Although digital prototyping now enables Dynamic Structures to forego having to build full-scale prototypes, it's still common to see parts of popular rides take shape in the company's fabrication yard before they're shipped to well-known theme parks. (Images courtesy of Dynamic Structures and David Cohn.)
Although digital prototyping now enables Dynamic Structures to forego having to build full-scale prototypes, it's still common to see parts of popular rides take shape in the company's fabrication yard before they're shipped to well-known theme parks. (Images courtesy of Dynamic Structures and David Cohn.)
 

As a result of using Autodesk software for digital prototyping, Dynamic Structures no longer has to build full-size mock-ups for any of its projects; however, some real-world factors such as weathering cannot be modeled or tested digitally. Dynamic Structures' current telescope project is the incredible Thirty Meter Telescope, which has a segmented mirror that is 30 meters (98 feet) in diameter and will enable observations with 10 times the spatial resolution of the Hubble Space Telescope. A full-scale mock-up of a portion of the telescope enclosure currently inhabits a corner of the Dynamic Structures storage yard. "We're testing connection methods for the insulation, seeing what happens when it's out in the weather for a while," said Breckenridge. "We have a similar mock-up sitting at 14,000 feet on top of Mauna Kea, because that's something you can't test in a digital prototype."

Every component of the Thirty Meter Telescope and its enclosure will be built digitally by Dynamic Structures using a combination of Autodesk software before the actual telescope is erected at the top of Mauna Kea in Hawaii. (Image courtesy of Dynamic Structures.)
Every component of the Thirty Meter Telescope and its enclosure will be built digitally by Dynamic Structures using a combination of Autodesk software before the actual telescope is erected at the top of Mauna Kea in Hawaii. (Image courtesy of Dynamic Structures.)
 

But every bit of the Thirty Meter Telescope — a 300,000-part model for the enclosure and a 300,000-part model for the telescope — will be built digitally by Dynamic Structures. By the time the design phase is completed, Breckenridge plans to deliver a complete digital model, including all the steel, concrete, cables, and piping. Design of the telescope should be completed in 2012, and the massive instrument should operational at the Mauna Kea observatory in 2018.

Dynamic Structures' company motto is "Anything you can dream, we can build." AutoCAD and the Autodesk family of products help the company deliver on that promise — in some pretty cool ways.


About the Author: David Cohn


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