3D Modeling Debate Spurs New Generation of CAD Tools

In some ways, it's the CAD industry's version of those
age-old debates, like the one over Coke vs. Pepsi, or republican vs. democrat.
As the discourse heats up over the merits of traditional parametric, or
history-based modeling tools compared with a new breed of direct modelers, the
only clear winner may be engineers, many of whom were previously shut out from
using CAD and who are now increasingly being presented with a range of powerful
and flexible options.

Led by the introduction of PTC
more than 20 years ago, parametric or history-based modeling
has dominated the CAD scene with a handful of direct or explicit modelers
hanging out there on the fringes. Parametric modeling leverages a history tree
to bring control and intelligence to the process of building CAD models. The
approach gained traction over the flexible, but functionally-limited, direct
modeling paradigm over the years because it was viewed as a more powerful and
automated way to create complex models, especially for large assemblies that
use families of parts.

Yet in the last several years, parametric CAD modelers lost
some of their luster. Users have run into roadblocks due to the complexity of
the history tree and they often complain about the inflexibility of the tools
for doing conceptual work and last-minute design changes. Their concerns
rekindled the decades-old argument, which has come back with a vengeance this
last year as newcomers like SpaceClaim
rolled out new direct modelers that address many of the shortcomings of the
original class of tools. Following suit, history-based CAD leaders like PTC, Siemens PLM Software and Autodesk have come to market with their own
variations on the technology, including a new hybrid breed that claims to marry
the benefits of both approaches.

In addition to ease-of-use and ease-of-learning, direct
modelers also have an edge when dealing with multi-CAD environments, a
situation made all the more common today due to globalization and the influx of
extended design teams. "Most companies are partnering with companies that have
lots of different technologies and most can't afford to have a seat of NX,
Pro/E, SolidWorks or Inventor sitting around in their design shops," says Monica Schnitger, a market analyst with Schnitger Corp. "By removing the
concept of the history tree, direct modelers function as a common ground

While there is a fair share of marketing hype surrounding
the competing modeling approaches, Evan Yares, a long-time CAD industry
consultant, acknowledges that a CAD revolution has indeed arrived - one that
will make CAD experts far more productive, while opening the door to non-CAD
technicians who have previously been shut out from effectively using the
technology. "All these different approaches are coming at the same problem - making
CAD easier to use," says Yares, who claims only 30 to 40 percent of engineers
currently use CAD effectively. "What is comes down to is the modern CAD program
has become so complex, with so many commands, that a normal person can't run

Separate, But Equal

That was the whole premise behind the introduction of
SpaceClaim Engineer, which was initially released to the market in April 2007
with the fourth
announced last month. The CAD upstart was predicated on taking
advantage of inexpensive PC hardware to unleash a new type of CAD tool that
would have appeal for the enormous untapped pool of designers and engineers for
whom traditional parametric-based tools were overload. "We see direct modeling
as the vehicle to break out of the glass ceiling of 1 million seats of solid
modelers sold and to get an order of magnitude of new growth in the market," says
Blake Courter, co-founder of SpaceClaim.

SpaceClaim Engineer doesn't attempt to unseat traditional
CAD tools, but rather appeal to engineers and designers upstream in the process
who are not traditional users of CAD. In addition, the software - which officials
are quick to point out requires minimal training - is positioned as an adjunct
tool within an engineering organization, optimized for quick conceptualization
of new designs or for preparing CAD models for analysis, according to Chris
Randall, SpaceClaim CEO. "This is 3-D modeling for engineers as opposed to 3-D
modeling for CAD jocks," he says.

PTC also views the market for direct modelers and parametric
CAD tools as mostly a separate audience. The company's flagship program,
Pro/ENGINEER, is ideal for the majority of instances when products are complex
and highly engineered, for example, or when the capture of engineering
constraints and relationships is critical to the success of the design - especially
if the product strategy is family-based or platform-driven. Yet even PTC, which
invented parametric, recognizes the door is open for a different approach. Last
year, PTC acquired
, one of the oldest and more successful direct modelers, along with
, and the company believes there is ample opportunity to grow the
explicit modeling category far beyond where it stands today.

While PTC doesn't rule out the possibility of eventually
bringing the two technologies together, for now, the company believes the two
modeling approaches appeal to distinct needs and audiences, thus are best
addressed as separate products. Engineers should choose between the two disciplines
based on the types of products they create, the time to market forces that
drive them and the types of processes that define their workflow. "If you try
to put two fundamentally different technologies together, it's somewhat of a
risk that you'll end up with the worst of both rather than the best of both," says
Justin Teague, PTC's senior vice president of CoCreate sales. "If you put too
much constraining technology in explicit, you might lose some of the
flexibility, whereas if you add too much freedom to parametric, you don't
really get the big bang for the buck that you're looking for out of that

Even so, PTC has been adding direct modeling capabilities to
Pro/ENGINEER, as well as sprinkling in parametric-like functionality into CoCreate.
Most of the major CAD vendors, including SolidWorks
and Dassault Systemes are doing a lot of the
same cross-pollination, adding direct modeling functionality to their existing
history-based products.

All Together Now

In fact, two of the biggest 3-D CAD providers have taken the
cross-pollination strategy to a new level, blending both modeling technologies
in a single product. Siemens PLM Software launched its strategy last June, with
, which it touts as a history-free, feature-based modeling
approach now offered in both its NX and SolidEdge CAD products. Based on a
proprietary application layer built on top of Siemens D-Cubed and Parasolid
software, Synchronous Technology employs live rules and solver technology to
overcome the order dependencies that have frequently dogged the performance of
history-based CAD tools. Through this technique, Siemens is able to preserve
the controls and automation advantages of a parametric modeling approach while
taking advantage of the flexibility, direct interaction and scalability that
have been the hallmark of direct modelers, according to Dan Staples, director
of SolidEdge product development at Siemens.

Autodesk appears to be taking a similar approach with its Inventor Fusion technology, which it
recently previewed and is slated for a future Inventor release. Fusion technology
will enable engineers to switch between parametric and direct workflows as it
make sense for a particular task and the software will take responsibility for
how to bring the two models together and to track the changes in a single
digital model. "Customers need a two-way street," says Andrew Anagnost, vice
president of CAD/CAE for Autodesk Manufacturing Solutions. "They want to be
able to directly edit a model when they want to and lock it down in parametric
when they want to. They want to keep parametric when they want it and throw it
away when they don't. That's what we've done with Fusion."

It's still too early to tell whether Fusion - or any of these new direct
modeling technologies - will ultimately give engineers that ultimate level of
design freedom. One thing is clear, however; we're finally getting to a point
where engineers may soon benefit from the best of both worlds. "Parametric has
some very good points, but it also has some weaknesses," says Ken Versprille,
PLM research director at CDP Assoc.
, a market research firm specializing in CAD and engineering. "Where we
are today is getting to the point where we can avoid the weaknesses."

That is welcome news for Jonathan Gamble, director of engineering for Magnet-Schultz of America Inc.,
a privately-held manufacturer of electromagnetic devices with headquarters in
Germany. A long-time SolidWorks user, Gamble was getting pressure from the
parent company to switch to the CoCreate SolidDesigner direct modeler, which
was used extensively at the company's German divisions. Yet, Gamble said he had reservations. The
company's FEA tool and PDM system were not compatible with the CoCreate
technology, and Gamble was concerned about how the lack of history-tree
technology would affect the design of families of parts, which was critical to
the Magnet-Schultz product family.

As a result, Gamble opted not to switch and keep both tools in house.
Still, he's pleased by all the recent activity related to bridging the worlds
of direct modeling with history-based CAD. "There's room for both. The trend I
see is that history-based modelers are starting to incorporate direct modeling
features. So in five years time, we'll have the best of both systems," Gamble

All aboard the Direct Modeling Train: See how the new hybrids and direct modeling options stack up. Learn More

Watch the Webcast:

Want to know more about the strengths and weaknesses of
indirect and history-based CAD tools and how you can leverage both technologies
as part of your development organization? Tune into our webcast where a panel
of experts wades in on the developing trend. Watch Now

Comments (0)

Please log in or register to post comments.
By submitting this form, you accept the Mollom privacy policy.
  • Oldest First
  • Newest First
Loading Comments...