Term Paper on Using a case
study or project you have previously undertaken, describe the factors
underpinning the effectiveness or otherwise of an IS within an organizational
setting.
Too many proprietary CAD systems make
interoperability impossible. But the situation is about to change.
It wasn't long ago the only way to get a CAD model from one system
to another was to first translate it into the IGES format and then
translate it into the system at hand. But just as translating spoken
languages sometimes mangles the original messages, this so-called
neutral-file format could deliver geometry that only resembled the
original model. Passing geometry through IGES is likely to separate
surfaces at edges, erase essential text, and give blends the heave
ho. In the parlance of CAD gurus, the neutral file format does not
encourage interoperability.
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The IGES format was supposed to provide a conduit for moving
geometry built in one system to almost any other. In a perfect
world, for example, a designer should be able to create geometry,
send it to an analyst for strength studies, and eventually to
manufacturing for production without needing cleanup or
modification.
But talk to people on the shop floor, and you'll find that cleaning
or fixing models is not the exception - it's the rule. Mold shops in
particular get models from almost every available CAD system. They
come in IGES, the widely used DXF format, the international STEP
format, and the ACISŪSAT format. And when manufacturing people don't
have a nearly identical CAD system on the receiving side, they have
to tweak and adjust models until they have geometry for good tool
paths. “Logica launches MMS interoperability solution Logica, the
supplier of mobile messaging and mobile payments, has announced that
has become the first company to deploy a proven MMS intercarrier
messaging solution with a unnamed mobile operator.” (Logica launches
MMS 2002)
Flawed files are so pervasive that a few automakers solve the
problem heavy handedly by insisting that suppliers use only their
approved brand of software. Smaller companies dealing with several
automakers must then maintain at least one of every approved CAD
system. The method might solve interoperability or translation
problems for the big boys, but for third and fourth tier suppliers,
maintaining several CAD systems produce a heavy support burden that
consumes many thousands of dollars.
There is a light at the end of the tunnel because one company is
delivering solutions to this interoperability problem - Spatial
Technology Inc. Spatial's ACIS 3D modeling kernel, the de facto
modeling standard, delivers solid, surface, and wire-frame modeling
to developers of CAD software, NC packages, analysis programs, and
dozens of other products. Departments using ACIS-enabled
applications can import SAT models from any of the over 180 ACIS-enabled
applications, such as Autodesk's Mechanical Desktop, Applicon's
Bravo, Baystate's CADKEY, Ashlar's Vellum Solids, VDS's IronCAD, or
Knowledge Revolution's Working Model 3D, and read them flawlessly.
The SAT interoperability works. The good news is about to get
better. Spatial's ultimate goal is to let anyone using an ACIS-enabled
CAD system bring in a design, regardless of where it was created,
and automatically turn it into usable geometry - watertight models,
good enough for finite-element analysis, manufacturing, or other
engineering functions.
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With the upcoming ACIS 5.0 release,
the "interoperability release, " this goal is becoming a reality. A
peek at ACIS 5.0 provides a look at impressive and growing
capabilities available from no other single source. For the first
time ever, engineers can use any model, regardless of where it's
generated. “A more viable approach is to achieve large-scale
interoperability via a network-based solution, using similar
principles as communications networks used by Internet providers and
voice carriers. Such a network would connect existing systems into
regional, statewide or national systems to create a private Intranet
for multi-agency interoperability without requiring the purchase of
new end-user equipment. ” (Herther 2002)
Users of ACIS-enabled applications can successfully read SAT files
from other ACIS-enabled systems and immediately use them. But model
flaws can creep into SAT files coming from either legacy or
proprietary non-ACIS based applications. Flaws show up in many
forms, such as gaps in geometry or surfaces that don't meet at
edges. In Spatial' s vocabulary, the model fidelity is low and
suffers from a lack of precision. Even for this geometry, Spatial
now has a few tricks up its sleeves.
The soon-to-be-released ACIS 5.0 is
Spatial's "interoperability release." For the first time ever,
technology will be in place to let engineers turn a wider range of
flawed geometry into `watertight' models for almost any downstream
operation. ACIS 5.0 will include enhancements to the company's
groundbreaking ACIS Healing Husk, which turns low- fidelity models
into high-fidelity SAT models. And for those models that just can't
be fixed, ACIS 5.0 has capabilities for working with low tolerance
models. The result? Interoperability between all applications -
either ACIS-enabled or proprietary non-ACIS based. A review of the
unique blend of technologies will provide a glimpse at how Spatial's
new interoperability solution works. Key features include:
* The high fidelity (precision) of ACIS
* Data translation
* Healing
* Tolerant modeling
* Viewing
Interoperability between ACIS-enabled
and non-ACIS systems is made possible by the ACIS kernel's
high-fidelity modeling. So what does this high-fidelity mean? If all
geometry could be described by classic, closed equations, such as
lines, arcs, conics, spheres, cubes, etc., then solid models could
provide an exact representation of real-world parts. But some
geomesuch as lines, arcs, conics, spheres, cubes, etc., then solid
models could provide an exact representation of real-world parts.
But some geometry, such as free-form surfaces, can't be defined by
these classic, closed equations. For these elements, kernel modelers
use mathematical representations, such as B-splines. And different
kernel modelers may have different algorithms for capturing these
elements.
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The degree to which these different algorithms accurately represent
real-world parts is a measure of "fidelity." In addition, the
precision of the representation, mathematical operations, and
storage of models contributes to the total "fidelity" of a solid
model.
* ACIS is the standard for high-fidelity modeling in terms of both
precision and topology richness for representing real-world parts:
* ACIS performs mathematical operations and stores models to a
precision of 10-6, which is a precision greater than any other 3D
solid modeling kernels.
ACIS also has the richest set of
topology (wire frame, surface, solid, hybrid, non-manifold) and the
broadest geometry coverage (analytic, NURBS, procedural) for
representing the original intent of a design.
Once geometry is raised to the accuracy of the high fidelity ACIS
SAT file, it can go anywhere. The precision of ACIS has impressed
many others. Data translation begins the process of changing
low-fidelity non-ACIS models into high-fidelity ACIS SAT models.
ACIS-enabled applications use Spatial's Translators Husks or other
third-party data translators to turn models stored in different file
formats, such as VDA-FS or IGES, into ACIS SAT files. (An ACIS Husk
is an optional library of task-specific functions that software
developers can plug into their ACIS-enabled applications).
The German Automobile Manufacturers Association wrote VDA-FS, a
European standard for the transfer of surface data between
dissimilar CAD/CAM systems. The neutral file format allows
exchanging geometry, topology, and annotation data. Spatial
partnered with GSSL of India to produce the ACIS VDA-FS Translator
Husk to work with the German standard. Spatial also worked with GSSL
to produce the ACIS IGES Translator Husk to work with IGES files. In
1999, Spatial plans to introduce a STEP Translator Husk.
Both the VDA-FS and IGES Husks perform limited cleanup and repair of
models, and compensate for some subtle differences between VDA- FS
or IGES implementations by various CAD applications. The Husks also
provide user-controlled options to tune the accuracy of imported and
exported files.
Once a model is translated into a SAT file, and if the file is in
need of repair, an ACIS-enabled application can fix the model using
the ACIS Healing Husk, the first widely available technology for
correcting model flaws. Spatial first released the Healing Husk in
March 1998. This month, with ACIS 5.0, Spatial introduces enhanced
capabilities for its ACIS Healing Husk. Here's a glimpse at how the
Husk works. The Husk's analysis software first checks that trimming
curves are in tolerance of the surface, and that two faces sharing
an edge are within the edge's tolerance. Other checks by the Husk
include looking for faces that should be adjacent to one another.
“The SunPCi co-processor card is the latest addition to Sun's family
of PC interoperability solutions which enables Sun workstation
customers to work in the same e-mail, spreadsheet and other office
productivity applications as their colleagues in different
departments.” (NEW SUN CARD 1998)
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Next, the Husk checks to see whether
the surfaces can be simplified. ACIS can recognize the NURBS as
spheres, cylinders, and cones and translates them into primitives to
simplify the geometry. Then the Healing Husk provides information
back to users about where problems are in the body. Users can decide
whether to fix the models automatically or manually in a process
called stitching. Stitching is a bit of a misnomer because it
doesn’t' t exactly bring edges together. Instead it adds topology to
a surface model that would allow turning surfaces into a solid.
After stitching, the Husk repairs
inaccuracies in the model. It performs a series of geometric
operations to improve the precision of face, edge, and vertex data.
Finally, the Husk corrects face normal, removes duplicate vertices
and faces no longer associated with geometry, and delivers a high
fidelity, "healed" ACIS SAT model.
The ACIS Healing Husk provides functions to either automatically
heal the entire body or manually heal individual parts of the body.
In the manual mode, users can attach attributes to poorly formed
model faces that might cause trouble for downstream users. These
attributes or notes can be stored for later examination. When the
flawed area does not affect users, they may wish to remove the
attributes and ignore the problematic geometry.
The ACIS 5.0 release introduces new
tolerant modeling capabilities in the kernel. Tolerant modeling will
let ACIS 5.0-enabled applications work with low-tolerance models
when geometry just can't be fixed through healing. The philosophy
chosen by Spatial is to work with tolerances on edges and vertices
rather than trying to turn poor geometry into perfection. The
approach is to tolerate imperfections and work around them Ž let the
software heal as much as possible and then attach tolerance
information to uncorrectable areas. Tolerant modeling is the
technology that will make ACIS 5.0-enabled applications essential to
every engineering department.
New tolerant edge and vertex
capabilities will let the software attach tolerance values to them.
So even when edges do not exactly intersect, they're brought close
enough to be useful. Some CAD systems put out models so flawed users
might import only a set of surfaces that should be a solid. Two
edges might be stitched to one tolerance and another two edges to a
different tolerance. Tolerant edge technology will let users work
with these flaws. The last component of Spatial's new
interoperability solution is its viewing technology. Spatial has
recognized that not everyone needs to modify geometry. Just
examining it might be enough.
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The ACIS 3D Open Viewer makes ACIS SAT models conveniently and
widely available to an entire organization by letting its staff view
models in Microsoft Office applications, like Word, PowerPoint, and
Internet Explorer. Professionals in sales, marketing, finance,
publications, engineering, and support can create information-rich
3D multimedia presentations, documents, and proposals using models
developed in any of the over 180 ACIS-enabled applications. Users
can rotate, pan, or zoom these models, and control their background
and colors.
“Businesses also should address interoperability issues such as
encryption (in individual stores and across transport), access
control, replication, conflict resolution, content preservation,
mapping (threads and links), data consistency and large text
searches across environments. In addition, they may have to provide
many simultaneous users with optimum performance and handle multiple
data types such as image, voice, video and binary files.” (Cox 1997)
The ACIS kernel is established as a de facto modeling standard. ACIS
5.0 will cement the standard. Improved model interoperability
combined with tolerant modeling and healing technology are the best
reasons yet to take advantage of applications based on ACIS 5.0. And
there are others. For example, Spatial's top- notch development team
has delivered more impressive features with ACIS 5.0 - all at an
industry-leading pace - including new selective Booleans, enhanced
blending capabilities, new bending functionality, and additional
error-feedback features. New selective Booleans allow combining two
or more bodies with greater flexibility and speed by letting users
keep or discard a portion of these combined bodies. Users can pick,
color, and highlight portions of the model they wish to keep or
discard.
In ACIS 5.0 bending has been repackaged for far easier use. A user
can now bend a part of a body by specifying where to bend it and
between which limits, saving incredible amounts of time. For
example, users can take a straight metal cylinder and bend it
quickly and easily into a bicycle handlebar. Moreover, the speed of
bending has been greatly improved and intelligence has been added to
automatically determine which connected parts of a body also have to
be bent.
The new spray system boosts the helicopter's productivity by
increasing the pesticide-tank capacity so the aircraft stays
airborne longer. Previous systems used rectangular metal tanks
attached to the underside of the aircraft. The tank volume was
limited by the need to clear the landing gear and communications
equipment on the helicopter. Vellum Solids made the design task more
manageable because it's based on the ACIS 3D modeling kernel which
allows designing with wire frame, surfaces, and solids in one model.
Most midrange solid-modeling programs make it necessary to model the
tank only in solids because they do not offer surface modeling.
Several are just beginning to include rudimentary surfacing
functions. Such programs would require creating many different solid
primitives representing various pieces of the tank. The designer
would have had to position them correctly in relation to each other
and then use Boolean commands to join them or subtract them out.
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The open-hardware architecture of the
PC bus often gets credit for fueling the personal computer
revolution. In a similar way, the open- software architecture of the
ACIS 3D modeling kemel works as a geometry bus, driving
"plug-and-play" compatibility and freedom of choice in
solid-modeling systems. The kernel is a foundation on which over 180
companies have written applications for special engineering
functions. Models move seamlessly among these applications via the
ACIS Geometry Bus by using the industry standard ACIS SAT file
format. This means a wide range of engineers can use a single model
throughout the product development process, from concept to
manufacturing, using applications from multiple vendors without the
hazard and burden of translating data. There is no need to suffer
the drudgery and time wasted in fixing broken models. Such essential
repair is the most time consuming problem for shops and facilities
using high-cost closed proprietary design and manufacturing systems.
The ACIS 3D modeling kemel provides a clear route around that
roadblock.
References
Cox, Nancy, “Bridging The Interoperability Gap”, Network Computing,
03-01-1997, pp p. 112
Herther, Jay, “The interoperability
quandary”, Mobile Radio Technology, 08-01-2002
“Logica launches MMS interoperability
solution”, Europemedia, 11-21-2002
“New Sun Card Provides Workstation
With Pc Compatibility” Vol. 11, Computer Workstations, 10-01-1998,
pp. 4-5
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