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| By Paolo
Velcich, Industrial Designer, Korum Design
It was a crazy schedule from the
start
SORA's goal was to have a new line of
mid-sized tour buses ready in time for the annual trade show in
Verona. Designed for operating on the tight mountain roads of the
Italian Riviera, smaller buses also appeal to other European tour
operators since many cities no longer allow large buses in the city
center.
After much discussion during January and
February 1998, the decision to develop the new buses was finally made.
A development team was formed and tasks assigned. That left us only
six months for the entire design and development process,
including the August vacation (yes, everything stops in Italy during
August).
Since I knew the first models would be
based on MAN 8.0 and 9.0 meter frames, I started working on some ideas
in Rhino. But the rest of the team didn’t start until April,
when the SDRC IDEAS systems were added to the two existing AutoCAD
drafting seats.
By the end of April, my first
preliminary sketches were proposed, and some basic shapes were passed
to the engineering team to develop the steel frame.
Integrating the development
process
To save time and avoid errors, we knew
we had to integrate the development process. The project designs had
to be updated at each step to integrate the experience of skilled
prototypers, metalworkers, and coach builders with the sophisticated
computer tools we were using for modeling and analysis.
Rhino's easy file exchage key
to the project's
success
It was Rhino's
ability to share 3-D models among
applications that let the
designers and the engineers to share models, parts, and data. This
allowed for quick and accurate translation of the conceptual ideas
into engineering, detailing, analysis, manufacturing, and marketing
information.
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The Project
Europa, a new
line of mid-sized buses designed for tour operators on the tight
roads in the mountains of the Italian Riviera.
The
Designer
Paolo Velcich
Korum Design
Viale
Tricesimo 5/6
33100, Udine,
Italy
The Company
Carrozziera SORA
srl., Osoppo, Italy, a small highly qualified Italian coach builder
who also specializes in customizing vehicles for disabled people.
The Team
The internal team
included the project director, a CAD operator, and a couple of
assistants in charge of purchasing and planning.
The external
team included an industrial designer (Paolo Velcich), an engineering
team, and a prototyping shop.
The
Software
Rhino for
conceptual design, surfacing, detailing, and model translation.
I-DEAS for
mechanical design.
ADAMS for
simulation.
AlphaCam for CAM.
The
Hardware
Modeling was
performed on various ordinary Pentium/NT machines, ranging from 200
Pro to PII/300, nothing special.
SGI
workstations were used mainly for analysis and simulation.
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Concept
development
Since we were in a rush, I had to make some
quick decisions and let the engineers go with the frame design. I soon
found myself with some very rigid constraints. For example, we didn’t have
time for a new windshield mold, so we had to design everything around the
dimensions of an available windshield.
I had played with some early designs on
Rhino as it's very quick and easy for manipulating surfaces. I was a
little skeptical about the quality of Rhino surfaces, so I planned to use
I-DEAS for modeling most of the surface skin.
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In I-DEAS, I modeled parametric solids
that perfectly matched the underlying frame. I sketched and verified
curves on cross sections that crossed the cabin at different levels,
then lofted and swept some surfaces (all under parametric control).
Finally, I cut the final shape out of the solid.
It was at that point that I switched
back to Rhino, because it was unnecessarily complicated and
time consuming to add cuts and details to the skin in I-DEAS. I
exported the whole model including the frame, wheels, seats to Rhino
via IGES without any problem.
Working in Rhino, I first removed
all the unnecessary curves and points. Then I joined the surfaces
together and divided
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them by layer to keep the work as clean
as possible.
I soon discovered Rhino is really
exceptional for quick but accurate conceptual work. The interface and
its user friendliness are really important and make the difference
when you're in a hurry. I think I'm able to "sketch" ideas in Rhino
almost as fast as I can on paper.
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Details
added
During the development of some parts of the
coach, especially the front and details on the back, I had to test several
different air vents, light housings, bumper curvatures, and other small
but important details.
Rhino let me place hand
drawings/sketches as bitmaps in the viewports and scale them to fit the
model. I used my design sketches and the scanned images from the real
front lights to design curves that I used to cut holes, trim surfaces, and
make window openings.
Rhino is a great tool when you need
to sketch on surfaces and add details, holes, and bends. You can project
curves on surfaces, draw normal to surfaces, blend between surfaces,
split, trim, and stretch. You can do almost everything, and you do it
intuitively, easily, and quickly.
Rhino was surprisingly fast even with
very large models on an ordinary PC.
At the end of this task I was very happy to
see that I was able to re-import the model to I-DEAS keeping the surfaces
consistent and watertight. When you transfer models via IGES, you lose the
parametric properties, but I-DEAS accepted the surfaces I modeled in
Rhino and was able to work on them.
Simulation studies
The detailed Rhino model was essential for
the interior design process, where advanced composites techniques were
used for cabinets and other parts. Virtual mannequins were also used for
human factors in the interior design process. The same model was also used
in advanced simulation for the noise reduction.
CNC milling
IGES exchange of 3-D data allowed for
successful interfacing with CNC tooling. I had to do some undercuts on the
rear light housing that turned out to be much easier in Rhino. Then
I was able to export the model both to I-DEAS and to the CNC machine. We
tested the Rhino model on both Mastercam and AlphaCam and actually
manufactured on a five-axis CNC milling machine via AlphaCam.
Show Time
The first bus was finished just in time for
the annual trade show in Verona. But it wasn’t finished early enough to
take photographs and have literature printed for the show.
The 3-D models helped again. All the
pictures for the communication and promotion were produced using raytraced
photorealistic renderings of the Rhino models.
Next
Thanks to the 3-D models and the great
tools, we were able to finish the next Europa design only a few weeks
after the first one was released.
Used again and again
Since SORA specializes in customization,
we’ll be using the Rhino models and the detailed library of
accessories again and again, to provide better and faster service to
SORA’s customers.
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