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Design World

New frontiers in simulation process automation

October 13, 2015 By Paul Heney Leave a Comment

By Bruce Jenkins, President, Ora Research

Automating the setup and execution of simulation and analysis problems has been a goal of both practitioners and software vendors since almost the beginning of the mechanical CAE software industry. After a long period of gestation and gradual progress, new solutions that benefit analysts, engineers and designers alike are coming to market at an ever-accelerating pace.

First wave: Scripting and custom programming
Early approaches relied heavily on scripting and custom programming. Repetitive, routine processes could be captured and reused in macro languages provided by CAE software vendors as adjuncts to their solvers and pre/post-processors. In addition, engineering organizations employed scripting languages such as Java and Python to build powerful, sophisticated layers of automation on top of their commercial analysis tools.

These approaches were a significant advance over having to set up every simulation problem entirely manually. A common misconception about CAE is that long computer run-times are the chief constraint on the analysis department’s ability to provide answers quickly enough to keep up with the pace of an overall product development project. But in reality, the time and labor required to set up models and input conditions for crash simulation, thermal analysis, and simulation of many other complex physical phenomena can far exceed the solver run-times for such problems. As an aerospace engineering manager once told us, “When it takes six weeks to prepare the input, the six-hour run time is irrelevant.” Automating problem set-up through scripting and programming helped relieve analysts of much of this tedious, time-consuming labor.

However, as powerful as this approach can be, it has significant limitations. Often narrowly case-specific, custom scripts are generally applicable only to the focused range of problems for which they were originally conceived. They tend to be tightly bound to the specific solvers and pre/post-processors for which they were first written, and require substantial rework to incorporate new tools entering the engineering organization. And their value is most often to help expert analysts work more efficiently and productively—they often do little to help make simulation and analysis capabilities available to engineers and designers outside the analysis department.

Second wave: Process automation frameworks
To move beyond these limits, a second wave of simulation process automation has gained momentum over the past decade-plus. This consists of environments and frameworks for simulation workflow capture and automation, often featuring drag-and-drop workflow editors that let analysts readily set up sophisticated process flows that can call functionality from a wide range of modeling, analysis, pre/post-processing and reporting software tools, and control data flows among them.

Once defined and validated by CAE experts, these workflows can often be used safely by non-experts—that is, engineers with expertise in their discipline, but without advanced training in CAE tools. Leading examples include Altair HyperWorks Collaboration Tools, ANSYS Workbench, ESI Virtual Integration Platform, MSC SimManager, Siemens Teamcenter Simulation Process Management, SIMULIA Simulation Lifecycle Management and others.

This approach to automating simulation processes has yielded substantial productivity gains for expert analysts, while at the same time capturing their expertise and making it available to engineers outside the analysis department. However, practitioners report that often enough, these solutions can still suffer from some of the same limitations as custom programming. What we hear most commonly is that when a problem being studied turns out to vary too greatly from the idealized scenario for which the automated workflow was constructed, the system freezes up, breaks down, or requires exactly the kind of manual intervention it was intended to eliminate.

Much of this is because the rules captured in these workflow templates are often based on the physical geometry of the generic product class whose design and analysis a given template is intended to automate. As any design progresses, changes to geometry or topology are frequently found to be necessary. But when these changes go too far afield from the generic model captured in the automation template, the rules fail. Software vendors are well aware of this limitation, and some have devoted substantial effort to remedy it. But we continue to hear from practitioners that more development is needed for this approach to scale across a sufficiently wide range of product families, initial design possibilities, and likely design changes to work in all or even a majority of their real-world use cases.

Third wave: Simulation apps
More recently, a third approach has emerged: simulation apps. These provide sophisticated simulation capabilities packaged as easy-to-use, tightly focused apps that automate the design, analysis and verification of a specific type of product, often tailored to the needs of a specific user company. In this approach, the expertise of an engineering organization’s analysts is captured as rules in a set of templates that automate the design of a specific class of product. In use, the templates call on general-purpose modeling, simulation and analysis software for geometry creation and modification, mesh generation, physics calculations in the various disciplines involved, and results presentation in the form of an optimized, validated design solution.

Ball bearing SmartApp. Source: Front End Analytics and EASA
Ball bearing SmartApp. Source: Front End Analytics and EASA

How simulation apps escape some of the limits of older approaches is by capturing the expert rules based on the functional architecture of the product family, instead of on the geometry or topology of particular designs. This is what can make the templates robust even across significant geometry, topology and configuration changes, and across an entire product family. Automation templates constructed on this basis allow any user, expert or non-expert, to explore alternative architectures, and to swap out entire components to find the best design most effectively. Most important is that these apps, designed and certified by experts, are immediately usable by engineers and designers without requiring specialized training—and make the full power of the underlying simulation and analysis tools available, safely and reliably.

Also important to understand is that, for now, simulation apps are not only solution-specific, but also need to be company-specific to have their greatest impact. Every company that uses simulation in its engineering processes has developed best practices using particular simulation codes. Thus, solution providers need, at the least, to customize a “starter” app to conform exactly to the company’s best practices, in order for the company’s experts to embrace these tools, and for everyone in the organization to trust the results they produce.

Equally important is that simulation apps are not just a vision for the future, but are being deployed and delivering payback today. Products as diverse as automotive drivelines, integrated circuits, space-based optical sensing systems and others have all featured in case-study presentations of where simulation apps have been successfully applied and proven in production situations.

Hydraulic rod design example SimApp. Source: Comet Solutions
Hydraulic rod design example SimApp. Source: Comet Solutions

Pioneering software and service providers and offerings in this area include Comet Solutions SimApps, COMSOL Multiphysics Application Builder, EASA, Front End Analytics SmartApps, Xogeny and others. In short order we expect to see growth of a rich ecosystem of app development tools and frameworks, app development service providers, and off-the-shelf suites of product-specific apps ready for individual end-user companies to customize by capturing and embedding their in-house experts’ knowledge and best practices.

 

Filed Under: CAD Blogs, Design World

New Tools In GrabCAD Workbench Reduce File Management Woes

November 19, 2013 By Barb Schmitz Leave a Comment

A common headache among engineers—especially at small to mid-size companies—is finding the right way to safely and efficiently manage, share and view CAD models. At larger companies, PDM and/or PLM systems are often in place to control the file management process, but a staggering 60% of engineers don’t have access to PDM/PLM systems. The end result can be a chaotic, often inefficient process that can lead to costly errors and a lot of wasted time and rework.

PDM and PLM systems offer file management tools but come with very high upfront and ongoing costs, often putting them beyond the budget reach of smaller companies. Many of these systems also take a long time to install and learn to use. Existing systems are also typically designed for internal use, making it difficult to share CAD files with partners and suppliers outside the firewall.

Another issue with current PDM/PLM systems revolves around the lack of Web-based tools to collaborate with non-CAD users. This is a serious failing of current offerings, considering the fact that 60% of engineers go through the somewhat arduous process of copying and pasting screenshots into a slide deck at least once a month to share product data with non-CAD users.

Bringing collaboration and file management to the cloud

The folks at GrabCAD realized that these pain points weren’t being addressed by current solutions in a cost-effective way and have added CAD file management tools to their Workbench product. Workbench is a cloud-based collaborative product development platform that enables users to manage, share and view CAD models with no upfront—or ongoing—IT investment.

Approximately 15,000 users are already signed up and are using Workbench to collaborate and share CAD models with suppliers, customers and partners. Adding file management capabilities will enable these users to automatically sync their desktop files to cloud projects, track file dependencies, instantly see version differences using a Compare tool and resolve conflicts.


By being cloud-based, Workbench eliminates the cost, hassle and risks of managing a new software and requires no dedicated server, no configuration, no maintenance and no IT hardware or support. As a result, Workbench users can be up and running in minutes with nary a worry about hard disk failures or database backups.

The company will be releasing a Workbench plug-in for SolidWorks 3D mechanical CAD software  in a couple of weeks that will enable these users to access Workbench from within their CAD program. Give Workbench a try; it’s available for free through January 2014. After that it will be offered for a monthly subscription price of $25. Check out more info here http://grabcad.com/workbench.

Barb Schmitz
bschmitz@wtwhmedia.com

Filed Under: CAD Industry News, Design World, News

Taming the Upfront Cost of CAD

October 24, 2013 By 3DCAD Editor Leave a Comment

By Evan Yares, 3DCAD Editor

Taming the upfront cost of CAD
Winner of Design World/Siemens Engineering Design Contest, Steve Triplett, Owner of Trinity Frame & Fabrication in Dallas.

About a year and a half ago, I wrote an article for 3D CAD World, asking the question “Should you buy your CAD software—or rent?”

The thing that piqued my interest in the subject at the time was the release of a version of Solid Edge called Design 1, available only under a monthly subscription plan to members of the Local Motors community.

It was an experiment in social product development. Local Motors is an unusual car manufacturer: they use a co-creation process to design their cars, partnering with community members on their website. They hold periodic challenges, where community members compete to design vehicles.

Putting CAD power in the right hands

The Local Motors community is diverse, and includes industrial designers, engineers, students, mechanics, and hobbyists. The one thing that all members of the community have in common is that they are car nuts. They participate in Local Motors design challenges out of pure passion.

While some Local Motors community members are experienced (and occasionally professional) CAD users, there are many who have more enthusiasm than experience. Yet, enthusiasm can go a long way: When you provide a group of enthusiasts with best-in-class CAD tools, some will rise to the occasion, and create the kind of work that any professional would be proud of.

When Local Motors started working with Siemens PLM on the Solid Edge Design 1 program, their goal was to empower their community; to find a way to put professional CAD tools in the hands of their community members, at an affordable price point.

They realized that the upfront cost of professional level CAD software was simply prohibitive for most of their community members. They needed to find a way to lower the barrier to entry.

Why did they choose to work with Siemens PLM? The simple answer is that they talked to several CAD vendors (you may be able to guess who), and Siemens was the one that responded favorably, and was open to the idea of offering a high-quality CAD tool at a low monthly subscription price point.

Software licensing is hard

For any CAD software vendor, the decisions about how to license their software are a pretty big deal. They’re not things that can be decided with the flip of a coin. Pricing, distribution channels, licensing terms, and more are all interrelated, and have to be thought out carefully, in context.

There are a diverse set of factors that drive licensing decisions, including corporate ownership structure, licensing terms for software components, sales channel structure, regional market differences, and customer expectations.

If a hypothetical vendor selling a mainstream MCAD product in the typical fashion—with an upfront license fee, plus annual maintenance/support fees—wanted to move to a subscription model, where customers pay for the right to use the software for a period of time, what would it take for them to do it?

There are the obvious steps of creating new software license agreements, and setting the terms and pricing. Beyond these, the CAD vendor faces a challenge getting buy-in from all the interested parties who need to be convinced that the change will at least not harm them, if not benefit them. These parties include not just customers, but also suppliers and partners. If the vendor doesn’t get it right, it can be a painful experience for everyone.

Solid Edge Subscription Plans

When Siemens PLM started offering Solid Edge under a monthly subscription license in early 2012, I was impressed. By limiting the offer to the Local Motors community, they’d found an effective way to prove the concept, without potentially alienating their existing customers or their partners. A few factors played into their ability to experiment. Back in 2011, Chuck Grindstaff, Siemens PLM Software president, reorganized the company, making the group that develops and sells Solid Edge an independent business segment. (Solid Edge is sold by a business segment of Siemens PLM Software, which is a business unit of Siemens Industry Automation, which is a division of Siemens AG.) Because their product is not the leader in its market segment, the Solid Edge team are actively looking for new ways to be innovative and displace their competitors.

By all appearances, the experiment was a success, as Siemens PLM is now opening up the Solid Edge subscription option (http://store.plm.automation.siemens.com/store/siplm1/en_US/home/ThemeID.33153000)—first to US and UK users, and later to customers in other regions.

This looks to be a very good program. It is a true month-to-month subscription, and includes both web support and partner (reseller) support. Users can choose between four different levels of Solid Edge—from Design and Drafting, all the way to Premium. These are the full commercial versions of Solid Edge—exactly the same software that users get when they buy perpetual licenses.

This subscription plan will be attractive to a variety of users:

Those working on short-term projects
Those with peak demands for extra seats
Those with short-term demands for advanced features
Those who can’t afford the upfront costs of a permanent license
Those with little or no software budget
Those with delayed software budgets
Those with contract-based projects
Those who are using competitive products, and want to try Solid Edge
Those who need to modify (direct edit) customer or vendor provided CAD files
Those who are not CAD professionals, but who would like the chance to work with “grown-up” CAD software

This is not a sneaky deal, intended to attract you with a low upfront cost, and lock you in with higher costs on the back end. Users can subscribe for a single month, and cancel if they desire. Their CAD files will be completely readable in any commercial copy of Solid Edge. Users can also upgrade and downgrade anytime they want to, depending on their needs at the moment.

The monthly subscription plan is not a replacement for the existing perpetual license plan. It is just an alternative. The monthly subscription plan is priced so that 3 years of subscription is about the same cost as a perpetual license with 3 years of maintenance. For users, the choice between buying a monthly subscription or a perpetual license comes down to cash flow and flexibility.

Too often, I’ve seen license plans for CAD programs that seemed to be more about the vendor making money than serving the customers’ needs. I had a feeling like it was a game of three-card Monte, where the vendor wouldn’t let me see all the cards.

In this case, the Solid Edge people are showing their cards. But I think it’s more due to enlightened self-
interest than altruism.

Because of a combination of business and technical factors (not the least of which is the fact that they own Parasolid, D-Cubed, and most all of the critical technologies used to build Solid Edge), Siemens PLM can afford to offer a monthly subscription program with very attractive terms. They believe that providing more and better purchase and usage options for customers will help drive their long-term business. I think they may be right.

A contest to make an engineering dream come true

Professional CAD has always been relatively expensive and relatively hard to use. Not because that is the intent of CAD vendors, but because it’s the nature of the technology: A professional grade CAD program is probably an order of magnitude more complex than a typical “office” software application (even if you don’t count the advanced 3D mathematics.)

But, what if CAD’s barriers to entry could be lowered? What if the reach of professional CAD tools could be extended, to a larger community of users? What might be possible?

The combination of monthly subscription licensing and direct editing with synchronous technology have definitely lowered the barriers to entry for Solid Edge. Now an engineer with a great product concept can get access to a professional CAD tools that they can actually use, without needing to pony up thousands of dollars in advance.

That’s what gave rise to the recent Design World/Siemens Engineering Design Contest. We asked our readers: Do you have an engineering dream? Something you’ve thought about doing, but blew off, because you couldn’t justify the upfront cost of the CAD software? Possibly an idea for a Kickstarter project, a concept for a Burning Man mutant vehicle, or design to contribute to a non-profit project?

We were blown away, with more than 60 entries—judges from the Design World editorial staff, Siemens and Microsoft whittled the submissions down and finally selected a winner, Steve Triplett, Owner of Trinity Frame & Fabrication in Dallas. The basis of Steve’s idea is a rear engine driven reverse trike—two wheels in front, one in the rear—that is operable from a wheel chair.

In Steve’s concept, the chassis lowers to the ground to facilitate backing the chair into the vehicle from the front and then the steering nacelle closes in front of the rider. The vehicle then returns to normal ride height and the rider enjoys an unobstructed riding experience very similar to a conventional motorcycle. Current trikes for people with disabilities are of the “chariot” style, where the rider is behind the powerplant and enclosed in a box. Steve feels that this idea would benefit many paraplegics, as well as our returning vets, who have been injured and would like to ride.

Steve won a one year subscription to Solid Edge valued at $4,200, to help him make his dream a reality. He also will be receiving a Surface from Microsoft to help get his business up and running, valued at $850.

Siemens
www.siemens.com

Filed Under: CAD Blogs, CAD Industry News, Design World, Evan Yares, Siemens Blogs, Siemens PLM & Events, Simulation Software Tagged With: Siemens

More on Steve Triplett, Design World/Siemens Engineering Design Winner

October 21, 2013 By 3DCAD Editor 1 Comment

By Evan Yares, 3DCAD Editor

Recently, Judges from the Design World editorial staff, Siemens and Microsoft selected Steve Triplett, Owner of Trinity Frame & Fabrication in Dallas, as the winner of the Design World/Siemens Engineering Design Contest. More than 60 submissions were received for this online competition.

We asked our readers: Do you have an engineering dream? Something you’ve thought about doing, but blew off, because you couldn’t justify the upfront cost of the CAD software? Possibly an idea for a Kickstarter project, a concept for a Burning Man mutant vehicle, or design to contribute to a non-profit project?

More on Steve Triplett, Design World/Siemens Engineering Design Winner
Winner of Design World/Siemens Engineering Design Contest, Steve Triplett, Owner of Trinity Frame & Fabrication in Dallas.

The basis of Steve’s idea is a rear engine driven reverse trike—two wheels in front, one in the rear—that is operable from a wheelchair.

Steve said that he built his first engine driven cycle in 1969 at the age of 14.

“As a senior in high school, I built a drag bike chassis in a Vocational Machine Shop class and won a first place trophy at a major custom car show,” he said. “The hook was set!”

“I have been in the motorcycle industry most of my career. I attended Braniff Aviation A&P school in the late 70s to learn mechanical discipline from the best. In the 80s, I apprenticed under a master machinest to learn motorcycle frame building and general machine shop skills. I incorporated all my training into starting a motorcycle shop in 1994,” he said.

His shop specializes in frame repair, fabrication and prototyping. In 2013, the shop received its WMI (World Manufacturer Identifier) and is prototyping a handicapped three wheeler that can be operated from a wheelchair.

In Steve’s reverse trike concept—which was selected as the winning contest entry—the chassis lowers to the ground to facilitate backing the chair into the vehicle from the front and then the steering nacelle closes in front of the rider. The vehicle then returns to normal ride height and the rider enjoys an unobstructed riding experience very similar to a conventional motorcycle. Current trikes for people with disabilities are of the “chariot” style, where the rider is behind the powerplant and enclosed in a box. Steve feels that this idea would benefit many paraplegics, as well as our returning vets, who have been injured and would like to ride.

Steve won a one year subscription of Solid Edge valued at $4,200, to help him make his dream a reality. He also will be receiving a Surface from Microsoft to help get his business up and running, valued at $850.

“It is an honor to receive this prize,” he said. “It will help me to finish a dream project of mine using state-of-the-art technology. I am excited to have Siemens as a team member! I want to thank Design World for bringing me relevant market data and the opportunity to compete in this contest.”

Siemens
www.siemens.com

Filed Under: CAD Blogs, CAD Industry News, Design World, Siemens Blogs, Siemens PLM & Events Tagged With: Siemens

Winner chosen for Design World/Siemens Engineering Design Contest

October 17, 2013 By 3DCAD Editor Leave a Comment

By Paul Heney, Editorial Director

What if CAD’s barriers to entry could be lowered? What if the reach of professional CAD tools could be extended, to a larger community of users? Those questions gave rise to the Design World/Siemens Engineering Design Contest.

We asked our readers: Do you have an engineering dream? Something you’ve thought about doing, but blew off, because you couldn’t justify the upfront cost of the CAD software? Possibly an idea for a Kickstarter project, a concept for a Burning Man mutant vehicle, or design to contribute to a non-profit project?

Winner-chosen-for-Design-WorldSiemens-Engineering-Design-Contest
Winner of Design World/Siemens Engineering Design Contest, Steve Triplett, Owner of Trinity Frame & Fabrication in Dallas.

Judges from the Design World editorial staff, Siemens and Microsoft whittled more than 60 submissions down and finally selected a winner:

Steve Triplett, Owner of Trinity Frame & Fabrication in Dallas.

The basis of Steve’s idea is a rear engine driven reverse trike—two wheels in front, one in the rear—that is operable from a wheelchair. Current trikes for people with disabilities are of the “chariot” style, where the rider is behind the powerplant and enclosed in a box. Steve feels that this idea would benefit many paraplegics, as well as our returning vets, who have been injured and would like to ride.

Steve won a one year subscription Siemens PLM valued at $4,200, to help him make his dream a reality. He also will be receiving a Surface from Microsoft to help get his business up and running, valued at $850.

Siemens
www.siemens.com

Filed Under: CAD Blogs, CAD Industry News, Design World, Siemens Blogs, Siemens PLM & Events Tagged With: Siemens

Leveraging 3D CAD Data

August 13, 2013 By Evan Yares Leave a Comment

by Evan Yares, Senior Editor

In the 2013 State of 3D Collaboration and Interoperability Report, published last May, Chad Jackson, Principal Analyst at Lifecycle Insights, asked the question, “Have we finally realized the vision of fully leveraging the 3D model?”

In the survey on which the report was based, respondents were asked about their use of 3D, both on the critical path (within engineering and manufacturing), and off the critical path (in service, quality, training, technical docs, marketing, sales, and other areas.) The results show that the use of 3D on the critical path is stronger than its use off the critical path. Though the use of 3D in downstream processes is growing, it’s pretty clear that relatively few companies are even close to fully leveraging their 3D CAD models.

3d-models-on-off-critcal-path
When it comes to leveraging the 3D model, the use of this software for critical path applications, like engineering and manufacturing (top), is stronger than with off-the-critical-path applications (bottom), such as training documentation, marketing, sales, and service literature or applications.

To understand why industry is where it is with respect to the use of 3D, it might help to step back a bit, into the history of CAD.

While 3D CAD systems have been around nearly as long as 2D, for the first 25 years of the CAD era, 2D was dominant. It wasn’t until late 1980s, with the introduction of Pro/ENGINEER—the first commercially successful parametric solid modeling CAD system—that 3D really came into its own.

With Pro/E, designers could first create 3D models, then quickly and easily create associative 2D drawings. When they modified the 3D models, the 2D drawings were automatically updated. Pro/E provided the benefits of 3D, without forcing its users to abandon their long entrenched 2D drawing centric product development processes.

Pro/E was incredibly influential, and most competitive CAD systems (with the exception of those designed primarily for aesthetic surface design) adopted a similar approach, coupling feature-based 3D solid modeling with associative 2D drawing creation and annotation.

Throughout the 1990s, it was pretty common for designers to use 3D model data in downstream processes. Yet, it was not convenient, requiring use of 3D models, as well as annotation information from drawings.

As 3D CAD systems matured, their developers started including model annotation tools, so designers could add information needed for manufacturing (such as dimensions, tolerances, assembly notes, and so on) directly to 3D models. CATIA, Unigraphics, I-DES, and Pro/E each had their own proprietary tools of this type. The problem was that they all worked differently, and weren’t compatible with each other. With no recognized standard methods for creating model annotations, most companies continued to use 2D drawings for conveying and maintaining manufacturing information.

In 1997, driven largely by the aerospace and defense industry and the DoD, ASME started work on what would become the Y14.41-2003 standard for Digital Product Definition Data Practices. The objective of the standard was to support the use of either model plus drawing, or model alone, as a complete product specification. Y14.41 was the first of a group of standards that collectively defined what has become known as product and manufacturing information (PMI).

Today, there are at least five different ways that companies can use CAD:

  1. 2D drawing as authority (full definition in drawing, no 3D model)
  2. 2.2D drawing as authority + 3D model (full definition in drawing, model not distributed)
  3. 3.2D drawing + 3D model together as authority (partial definition in both)
  4. 4.2D drawing as authority + 3D model as authority (full definition in model, either full or partial definition in drawing, automatically generated from model)
  5. 5.3D model as authority (full definition in model, no 2D drawing)

The first classification here represents traditional 2D computer-aided drafting. The second represents the lowest level of 3D CAD. The third classification is the most common way datasets are structured in many mainstream manufacturing applications today. The fourth and fifth classifications represent how datasets are structured in organizations pursuing model-based definition (MBD) initiatives—particularly in aerospace enterprises.

2d-authority-model
A 2D authority model, fully defined

MBD
Model-based definition is one of a number of “model-based” initiatives, all of which have as their foundation the concept of using semantically rich models to represent the functional characteristics of a product. (Among the list of interesting model-based initiatives are model-based development and model-based design, both of which share the MBD acronym with model-based definition, but neither of which are related to model-based definition. They are initiatives related to the design of complex software systems and control systems, respectively.)

The concept of MBD grew out of a big vision concept called model-based engineering, and was itself, at one time, a very big vision concept. Fortunately, sane minds prevailed, and people involved with the MBD initiative focused their energies on making it pragmatic rather than aspirational. They focused on smartening-up 3D model data, to enable downstream usability. An MBD product model is not hard to understand:

It’s a combination of 3D geometry and PMI (including explicitly defined dimensions, tolerances, notes, GD&T, welding symbols, surface texture symbols, and associated data.)

3d-authority-model
A 3D authority model, fully defined using PMI

The PMI is semantic (readable by either humans, or computer programs), associative to the 3D geometry, and standards-based. Any number of views of the model can be composed, detailed, and annotated for specific downstream operations.

While MBD is often thought of as mostly being about “getting rid of drawings,” it’s really more about getting rid of the need to use drawings for things they’re not good for. In an MBD context, it’s still possible to create drawings in the traditional way, but MBD offers a better way: it’s exceptionally easy to create drawings that are 2D projections of the views included in the product model. These are generally simpler than traditional drawings, but they have the benefit of being 100% consistent with the model. There is never a question of which document is correct—the drawing or the model.

The process of implementing MBD in an organization starts with one important first step: Getting CAD software that supports PMI. Unfortunately, this first step also introduces one of the issues that’s held the acceptance of MBD back: lack of compatibility. While CATIA, NX, Creo, Solid Edge, SpaceClaim, and SolidWorks all support PMI, they do so in varying and inconsistent ways. And they each use proprietary data formats.

While it’s possible to get past many of the problems with the various implementations of PMI (often by the use of third party software), the experience of implementing MBD is going to be heavily flavored by the CAD vendor whose software you use. Probably.

STEP AP242
When the first standards development was done for PMI, an important piece was missing. Though ASME and ISO standards defined PMI, there was no neutral CAD file format that was capable of representing that information. Rather soon, however, the STEP AP203 format was updated to the “E2” version, which included support for PMI data. But, the support didn’t quite cross the threshold of “good enough.”

STEP-AP242-file-standard
The STEP AP242 neutral file standard will fully support PMI, as well as a diverse number of geometric representations.

Soon—likely in January—ISO will publish the STEP AP242 standard. AP242 is designed for long-term archiving of CAD data—which means that it will certainly get substantial support from CAD vendors. AP242 is also designed to provide close to full support for PMI. (There’s no such thing as absolutely complete support. There are always details that slop through the cracks.)

STEP AP242 may be good enough at representing both PMI data and 3D geometry that it becomes widely used as a primary file format in MBD initiatives on that basis alone. But what makes AP242 really interesting is a separate development, from several years ago: Direct editing CAD.

Historically, CAD systems have been great at editing their native files, and terrible at editing non-native files. Yet, to a direct editing CAD program, a STEP AP242 file is, for all practical purposes, a native file.

3DPDF
Over the last couple of years, with the support of the nonprofit 3DPDF Consortium, the 3DPDF file format has made great strides as a visual communication format for 3D CAD and MBD data.

Earlier this year, the US government updated MIL-STD-31000A, Technical Data Packages, to make it 3D MBD friendly. The new revision has a strong preference that physical product data provided to the government be defined and transmitted as 3D authority datasets. Interestingly, 3D PDF seems to hit a sweet spot, combining openness (PDF is an ISO standard), with the ability to accurately represent both 3D model data and PMI.

To date, 3DPDF has seen the most use in applications that involve human viewing. But the PRC 3D format (the preferred 3D representation for 3DPDF) includes an exact representation, which can be read and converted into NURBS curves by other applications (for example, SpaceClaim). Over time, it probably won’t be surprising if 3D PDF is used as an alternative to more traditional interoperability file formats, such as STEP.

Leveraging 3D
Bryan Fisher, of MBD360, one of the best known consultants in the area of MBD, feels that the time is right for leveraging 3D models. “Standards supporting PMI have been, and continue to be, actively developed. But, even though more work needs to be done, we’re well past the threshold of ‘good enough.’” Fisher stated. “Organizations of all sizes, in a variety of industries, have demonstrated significant cost reductions by implementing 3D model-based business processes.”

With the payoff being proven, and all the bits and pieces coming together to make the process of implementing MBD both less difficult, and less risky, we may actually be getting closer to realizing the vision of fully leveraging 3D models.

Lifecycle Insights
www.lifecycleinsights.com

Model-Based Enterprise
www.model-based-enterprise.org

STEP AP242
www.ap242.org

3DPDF Consortium
www.3dpdfconsortium.org

MBD360
www.mbd360.com

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Filed Under: CAD Blogs, Design World, General Blogs

The Design World dynamic design challenge

July 31, 2013 By Evan Yares Leave a Comment

Win a free dynamic design analysis of your mechanism. Get to market faster. Be a hero to your customers.

When NASA’s JPL landed the Curiosity Rover on Mars, I was impressed. Not just that they’d done it blind (because of the time-delay in communications from Mars), but also that they’d done it by dropping the rover on cables from a rocket-powered sky crane as it descended to the surface.

Think about that for a moment: That would be hard enough to do on Earth, where they’d be able to do full-scale physical testing of prototypes. Doing it on Mars, where the gravity is different from Earth, and where they had only one shot to get it right, took some serious engineering.

My first guess about how they did it was one word: Adams. And, it turns out, I was right. Adams, from MSC software, is possibly the best known multibody dynamics simulation software system, and JPL used it to simulate the process of dropping the rover onto the surface of Mars.

Cable 1

While I’ve known about Adams for years, I’ve generally not paid all that much attention to it, because it’s often used by rocket scientists and advanced dynamicists, not design engineers. It takes a lot of expertise to setup right, and just isn’t the kind of tool that the kind of people who I hang out with would typically feel comfortable using. (OK–I admit that I know a few people who actually are rocket scientists, one of whom uses Adams, but I think you get my point.)

Last year, MSC Software released a special version of Adams (called Adams/Machinery) that was designed for my kind of people. I wouldn’t have been surprised had MSC dumbed-down Adams to make it easier to use, but they did something very different: They developed a series of wizards, that could be used to design and analyze common machine subsystems, such as gears, belts, pulleys, chains, sprockets, bearings, and cables.

Flexible Gearbox

While Adams has long been able to design and analyze these sort of subsystems, the process has required a lot of expertise and work. That’s changed. The wizards in Adams/Machinery not only make the process easier, but they also allow the designer to adjust the level of fidelity of simulation, based on their needs.

Adams/Machinery can help designers solve some otherwise tough problems:

  • Analyze bearing contact force, and predict service life,
  • Predict load and performance of power transmission systems,
  • Predict how gear ratio, friction and backlash impact the overall system performance, like the output torque or the system vibration,
  • Analyze how the contact force between gears could change due to backlash effect,
  • Study how different gear parameters impact the stress distribution of the input shaft,
  • Predict how Bearing clearance affects the gear mesh,
  • Calculate the dynamic loading of the gear, bearing, shaft or any component in the system,
  • Calculate dynamic belt tension and how slippage would affect system performance,
  • And quite a lot more.

Not too long ago, I attended MSC’s 50th anniversary user conference. While there, I got to talking with Leslie Bodnar, MSC’s marketing director, about Adams/Machinery. It occurred to me that many of the engineers who read Design World magazine are involved in designing machinery that incorporates the kind of subsystems for which Adams/Machinery is optimized. It also occurred to me that many of those engineers never do multibody dynamics analysis, because they assume the process is too hard, or too time consuming. Or, perhaps, they might not even know it’s possible.

Serpentine Belt

I had an idea: What if, instead of using boring sample problems to demonstrate the capabilities of Adams/Machinery, MSC was to run an analysis on a really interesting real world problem, from one of our readers? It’s one thing for an engineering software vendor to brag about how good their software is, but it’s another thing entirely to step up and prove it on an actual customer problem.

So, I made Leslie a proposal: Design World would hold a contest with MSC, and ask our readers to submit real-world machine design dynamics problems. We would choose a really interesting one, and MSC would work side-by-side with that reader, to run a full Adams/Machinery analysis on the problem.

For the reader, the “prize” of winning the contest would be an analysis that could help solve a sticky design problem, and get their project done and shipped faster. For MSC, it would be a chance to “put-up or shut-up, ” by showing that not only is their software up to the task of running the analysis, but also that it’s easy enough for a mere mortal (as opposed to a PhD analyst) to learn to use. This wouldn’t be some simplistic sales demo: It would be a intimate customer engagement, where they’d need to deliver a real solution. Surprisingly, she said yes, she would do it.

So, I present to you the Design World Dynamic Design Challenge, sponsored by MSC Software. Choose your stickiest dynamic design challenge (it should include cables, bearings, gears, belts, sprockets, or chains), and visit the contest registration page. There, you can register, and tell us about your design problem. You can even upload pictures or videos. If we choose your problem as the winner, MSC will work with you to nail that problem to the wall, but good.

You might wonder: Will it be worth it?  Is entering this challenge, just to have a chance to win an analysis of your mechanism, really worth the effort? You might ask the folks at JPL. Multibody dynamic analysis has paid off pretty well for them.

 

Filed Under: CAE, Design World, Evan Yares, Featured, Simulation Software Tagged With: Adams, MSC

The failed promise of parametric CAD part 5: A resilient modeling strategy

June 25, 2013 By Evan Yares 3 Comments

bamboo-gardenThe model brittleness problem inherent with parametric feature-based modeling is a really big deal. And it’s something, honestly, that I don’t have a great answer for. I’ve even asked a few power users who I know, and their answers seemed to involve a bit of hand-waving, and a reference to having lots of experience.

While best practices are a potentially good step forward, they need to be straightforward enough that mere mortals (as opposed to power users) can follow them.

Around Christmas last year, I got a call from Richard Gebhard, an engineer’s engineer, who has made his living selling CAD, and training people to use it (including more than his fair share of power users), for longer than he would like me to admit. (I’m pretty sure I’ve been in the CAD industry longer than him, though.) Richard told me he had something he wanted to show me, and if I’d take the time to meet him, he’d buy me lunch.

What Richard showed me was a way of creating and structuring CAD models that made a lot of sense. It not only reduced parent-child dependencies, but it made them more predictable. And, more importantly, it made it a lot easier for a mere mortals to scan through the feature tree, and see if there were any grues (it’s a technical term. Feel free to look it up.)

Over the next several months, we had lunch several times. I made suggestions. He rejected some, accepted some, and thought about others. At the same time, he was bouncing his ideas off several of his best power users (including his son). By a couple of months ago, he had refined his system to the place where it would work impressively well with nearly any parametric feature-based CAD system. So, he went to work finalizing his presentation.

I had mentioned that Delphi, by patenting some of the elements of horizontal modeling, limited the number of people who could benefit from it. (Worse for them, they patented it, then filed bankruptcy. That didn’t help much.) Richard’s goal wasn’t to monetize his process. His goal was to evangelize it. To help CAD users—both power users and mere mortals—to get their jobs done better.

Richard and I had talked, over time, about what he should call this process. At first, I liked the word “robust.” In computer science, it is the ability of a system to cope with errors during execution. In economics, it is the ability of a model to remain valid under different assumptions, parameters and initial conditions. Those are good connotations. But, then I thought of one of my favorite examples of robustness. The first time I visited Russia, I noticed that the apartment buildings were built of thick poured concrete. Very robust. And nearly impossible to remodel.

Richard’s system wasn’t robust. It was resilient. So, he has named it the Resilient Modeling Strategy. RMS.

So far, I’ve written over 2,600 words, to provide some background on the problems of parametric modeling, and some of the solutions that have been offered over the years. But, after all that, I’m not going to tell you anything more about RMS. At least, not yet.

Tomorrow, Wednesday, June 26, Richard will present RMS for the first time ever, at Solid Edge University, in Cincinnati, Ohio. His presentation will start at 9:00AM local time, and will be in room 6 of the convention center. If you’re there, put it on your calendar. If not, you’ll need to wait until Richard gets back to Phoenix, and I publish a follow-up post.

RMS is not anything difficult, or fundamentally new. It’s just an elegant distillation of best practices, designed to work with nearly any parametric CAD system, and simple enough that it doesn’t get in the way.  It’ll help you make better CAD models faster.

Filed Under: Alibre, Autodesk, Creo, Design World, Evan Yares, Featured, Inventor, Pro/Engineer, Siemens PLM, SolidWorks Tagged With: Creo, Inventor, IronCAD, Solid Edge, SolidWorks

The failed promise of parametric CAD part 4: Going horizontal

June 25, 2013 By Evan Yares 12 Comments

In the early 90s, Ron Andrews, a senior product designer at Dephi’s Saginaw Steering Systems Division, became fed-up with the difficulties of editing parametric CAD models. So, he and a team of his colleagues, including Pravin Khurana, Kevin Marseilles, and Diane Landers, took on a challenge of trying to find a solution.

They came up with an interesting concept that they called horizontal modeling. Here’s a description of it from their patent abstract:

“Disclosed is a horizontal structure method of CAD/CAM manufacturing where a base feature is provided and one or more form features added to it to form a model. The form features are added in an associative relationship with the base feature, preferable a parent child relationship, but are added in a way as to have substantially no associative relationships with each other. The result is a horizontally-structured Master Process Model where any one form feature can be altered or deleted without affecting the rest of the model. Extracts are then made of the Master Process Model to show the construction of the model feature by feature over time. These extracts are then used to generate manufacturing instructions that are used to machine a real-world part from a blank shaped like the base feature.”

Here’s a picture that makes it clearer:

Horizontal Modeling

The simplest explanation I can give for it is this: You create a base feature, and bunch of datum (working) planes. You attach all the child features to those datum planes. Viola: no parent-child problems.

I admit that I’m not going to do justice to horizontal modeling in this conversation. There’s actually quite a bit to it, and it makes a lot of sense when coupled with computer-aided process planning (CAPP.)

Horizontal modeling has a handful of problems. First, it does a pretty good job of killing the possibility of having design intent expressed in the feature tree. Next, it works better with some CAD systems than others. (When horizontal modeling was in the news, SolidWorks had a problem managing the normals on datum planes, so it didn’t work too well.) The deadliest problem is that Delphi got a bunch of patents on the process, then licensed it to some training companies. From what I can see (and I may be wrong), none of these training centers offer horizontal modeling classes any more.

While, technically, you can’t use horizontal modeling without a patent license from Delphi, the concepts at its core are fairly similar to things that CAD users have been doing for years. A few years ago, Josh Mings posted on a couple of online forums that “Horizontal Modeling is just one word for it, you may also know it as Skeleton Modeling, Tier modeling, Sketch Assembly modeling, CAD
Neutral Modeling, or Body Modeling.” (It’s actually two words for it, but I get his point.)

Horizontal modeling is not a silver bullet solution for the problems inherent in parametric feature-based CAD. It’s just a best practice—a strategy for getting around the problems. It seems to be headed in the right direction, but it suffers from the complexity that comes from trying to fix too many problems at once.

Next: A Resilient Modeling Strategy

Filed Under: Alibre, Autodesk, Creo, Design World, Evan Yares, Featured, Inventor, Pro/Engineer, Siemens PLM, SolidWorks Tagged With: Creo, Inventor, IronCAD, Solid Edge, SolidWorks

The failed promise of parametric CAD part 3: The direct solution

June 25, 2013 By Evan Yares 5 Comments

Pull-PushDirect modeling—a syncretic melding of concepts pioneered by CoCreate, Trispectives, Kubotek (and many others)–has shown the most promise to cure the parametric curse.

Direct modeling is today’s hot CAD technology. PTC, Autodesk, Siemens PLM, Dassault (CATIA, but not so much SolidWorks), IronCAD, Kubotek, Bricsys, SpaceClaim (and certainly some other companies I’ve forgotten) all have their own unique implementations of it.

The common thread in direct modeling is to use standard construction techniques when modeling, and feature inferencing (or recognition) when editing. It’s easier said than done. It’s taken about 35 years of industry research to get to the place we are today—where you can click on a face of a model, and the system will recognize that you’re pointing to a feature that has some semantic value. And that’s not even considering the tremendous amount of work that has been required by legions of PhD mathematicians to develop the math that lets you push or pull on a model face, and have the system actually edit the geometry it in a useful manner.

For the CAD software, figuring out which way to edit a selection is almost a mind reading trick: A user clicks and drags on a part of a model. What would they like to happen? In some cases it’s easy: Drag once face of a rectangular block, and the system will just make it longer or shorter. But if the block is full of holes, bosses, and blends, it becomes a lot more complicated. What should the system do if you drag a face so far back that it consumes another feature, and then pull it back to where it was? Should the consumed feature be lost forever, or should the system remember it in some way, so it can be restored?

There are no right answers. It seems that no two direct modeling systems handle the decision of what is a “sensible” edit in the same way.

While direct modeling absolutely solves the model brittleness problem inherent with parametrics, it does it by simply not using parametrics. Even with hybrid parametric/direct CAD systems, the answer to the parametric curse is still to not use parametrics when you don’t need to.

The solution of “use direct modeling when you can, and learn to live with parametric hassles when you can’t” just isn’t very satisfying to me.

Next: Going horizontal

Filed Under: Alibre, Autodesk, Creo, Design World, Evan Yares, Featured, Inventor, Pro/Engineer, Siemens PLM, SolidWorks Tagged With: Creo, Inventor, IronCAD, Solid Edge, SolidWorks

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