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 The Company:
Direct Dimensions, Inc. (DDI) provides 3D
laser scanning solutions for complex modeling and manufacturing
problems. The company specializes in on-site laser scanning and
conversion of complex three-dimensional data into 3D computer models.
In business for 13 years, the Baltimore, MD-based company has a strong
presence on the East Coast, with businesses shipping parts to them for
scanning and modeling from all over the country. They also frequently
go onsite with portable scanning equipment such as Laser Design’s
Surveyor FA-Series portable scanner and the SLP-2000 probe with the
super-long 8” laser line for larger projects.
Direct Dimensions has customers in
virtually every industry including aerospace/military,
automotive, general industrial, consumer products, medical, and a strong
art and architecture focus. They laser scan parts of all sizes from
small to very large, and shapes from simple to complex, to use in many
applications including reverse engineering, inspection, and design.
DDI’s
customer for this scanning project was a 3D animation company that
specializes in aircraft cockpit ergonomics or human factors analysis.
The customer needed a 3D model of an existing cockpit within a large
commercial aircraft. Special attention was required in showing the
pilots’ positions and range of motion to various controls in order to
create an animation and other analyses. The final model was used to
make an animated 3D visualization of pilot interaction with the aircraft
controls. Arrangements were made so that the specific model aircraft
was available for the project.
The Challenge:
Direct Dimensions was called in to scan the
entire cockpit, providing enough detail to recreate an animation
scenario of the controls and pilot movements during a very tight
pre-specified time period. The two DDI engineers traveled onsite to the
aircraft maintenance facility; due to aircraft scheduling constraints,
they had only 8 hours on the vehicle to complete the scan of the cockpit
for the reverse engineering project. Without Laser Design’s long laser
line scanning technology, such an undertaking might take several days to
accomplish.
Lay public viewers
expect to see 3D animations perfectly replicate reality like they see in
a courtroom animation or as used on the nightly news. But modeling
reality is an inexact science and enormously difficult when dealing with
a real-world scene rather than a fictional locale, as in most video
games. “This was not as much an engineering project,” said the senior
project lead, “as it was a multimedia project, recreating a real-world
scene to be used for 3D animation.”
In addition to the
difficult time constraint for the onsite scanning process, a physical
challenge was the tight size of the cockpit. Within these close
quarters the DDI engineers needed to set up the LDI laser probe on the
Faro arm providing vantage points to the entire cockpit and all the
critical controls.
Also, scanning the dark colors and reflective
surfaces of the controls was a concern. Some laser probes can have
trouble capturing dark or shiny objects. The main control wheel was
especially problematic because it was dark and shiny.
Once the scanning
process was completed, the huge data set was to be reverse engineered
into an accurate 3D model of the cockpit so when it was animated the
scene would look very realistic. Fortunately DDI has the data
processing software, computers, and expertise to work with the extremely
large data sets that were produced from this cockpit scan.
The Solution:
Using the fast and accurate Laser Design
SLP-2000 laser, with an extra-long laser line length of up to 12-inches
and an 8-foot Platinum Faro articulated arm, the engineers planned and
then set up the scan environment in the cockpit. The data collection
phase of the project proceeded very efficiently using the SLP-2000 laser
which captured accurate detail and excellent resolution of
cockpit controls and features.
Scanning free-form
shapes and irregular surfaces, such as those found in a cockpit, is an
application especially well suited to a non-contact laser scanner on an
articulating arm. Because the scanning system projects a line of laser
light onto surfaces while cameras continuously triangulate the changing
distance and profile of the laser line as it sweeps along, the problems
of missing data on an irregularly shaped surface are minimal. The
operator moves the Laser Design SLP-2000 laser line back and forth over
the scan area until the entire surface is captured. The capture
progress is continuously monitored by the operator on the computer
screen. The system measures details and complex free-form geometry so
that the object can be exactly replicated digitally. Laser scanners
measure quickly, picking up over 75,000 coordinate points per second,
and generate huge numbers of data points to accurately describe the
scanned objects without the need for templates or fixtures.
Firstly, since
an aircraft cockpit is a relatively confined environment, the setup was
somewhat cramped. The portability and the ease of use of the
Laser Design SLP-2000 laser on the Faro arm system were essential to
completing the project under the severe time restrictions. The Faro arm
was positioned in the center-back of the cockpit because the laser could
scan most of the geometry from that vantage point. The pilot
and co-pilot controls move in unison when either side is being used, so
to scan the movements of the pilot’s side of the cockpit without
blocking the view, an assistant sat on the co-pilot’s side to work the
controls, and vice versa. The movements of the controls, especially the
rudder, were paramount to document, and by having one seat empty, the
scanner had a clear view of the controls when they were operated from
the other cockpit seat. The customer even brought in a representative
pilot to be scanned and to work the controls to provide a reference for
accurately visualizing the conditions and actions in the cockpit for the
animation.
Secondly, although the cockpit was very small
for setup and performing a scan, it was a relatively large and detailed
space to scan in such a short period of time. The locations of the
flight controls (sticks and pedals), the seats,
and pilots needed to be accurate within a tight tolerance for the
animation to be correct. The DDI engineers had to determine how to
gather enough data at the required accuracies in the required locations
and do it quickly enough to finish within the time constraints.
With the Laser Design SLP-2000, the
industry-leading longest line laser, the engineers initially performed
test scans at a high density, processed the data on the laptop computer
to check its accuracy and validity, then decided that a lower density
would still provide the resolutions required to document the positions
of the controls and the pilots and be much quicker. The SLP laser’s
extra-long line length gathered thousands of 3D point cloud coordinates
at ultra-high speeds. The DDI engineers coordinated the airplane
control locations with the hard geometry of the floor and bulkhead to
provide the important reference points and insure accuracy of the model
created from the 3D digital scan data.
Another scanning challenge was the dark
colors of the controls. The control wheel was especially problematic
because it was dark and also shiny. Laser Design’s SLP laser probe
design utilizes CMOS array technology instead of the older CCD array
used in most competitive probes which allows a wider range of specular
surfaces to be scanned.
However, the DDI engineers also decided to
use one of their experienced-based special scanning methods, blue
painter’s tape, to cover the handle to acquire even better data.
With a scanning strategy in place, the DDI
engineers began the series of scans required to cover the entire
interior of the cockpit. They set up the various scanning passes,
verified the data as they went along, filtered the data at the correct
rate for the application, and completed the onsite portion of the job,
all in the 8-hour timeframe, an amazing achievement which attests to
their expertise and professionalism.
The Results:
After scanning the
entire cockpit and returning to their facility in Baltimore, DDI’s
engineers used point-cloud processing software to process the massive
raw scan files into a highly accurate polygonal model in STL format. By
merging all the scan files together, a digital cockpit emerged that was
an exact replica of the original aircraft cockpit. From that model,
they then created a low-resolution version for use by the customer in 3D
Studio Max to produce the animation sequences.
The senior engineer
explained, “Success meant knowing where key items were within less than
⅛-inch. The customer needed to illustrate the specific positions of
controls and objects, but not the fine details.” With the cockpit
model, the animators could create a timeline and accurately depict a
sequence of events. “From a scanning perspective, the results we
obtained under challenging conditions were very good,” commented the DDI
engineer. “We have been called in again by the same customer to
document other vehicles digitally, so they have joined Direct
Dimensions’ list of satisfied customers.”
About Laser Design:
Laser Design, Inc. has been the leading
supplier of ultra-precise, 3D laser scanning systems and services
for over 20 years. Used for capturing the 3D
shape of objects with complex geometries and free-form surfaces, Laser
Design’s Surveyor line of automated and portable scanning systems are
ideal for 3D scanning applications involving inspection and reverse
engineering of complex shaped plastic and metal parts. The company’s
patented laser line-probe technology dramatically reduces scanning time
by collecting data substantially faster and more accurately than
conventional metrology technologies. Laser Design integrates
Geomagic software with its laser scanners to provide complete solutions
for reverse engineering and inspection applications.
Headquartered in
Minneapolis, the company also has Regional Technical Services and
Support Centers in Seattle and Detroit, and distributors throughout
Europe and Asia. Laser Design also operates GKS Inspection Services (www.gks.com),
an in-house service bureau division offering complete 3D scanning,
reverse engineering, and dimensional inspection services.
For further
information, contact Rick Passek, by phone (952-252-3412), fax
(952-884-9653), via email to
sales@laserdesign.comm or visit Laser Design’s web site at
www.laserdesign.com.
About Direct
Dimensions:
Direct Dimensions,
Inc. (DDI) provides unique solutions to complex modeling and
manufacturing problems. We specialize in the on-site application of
digitizers,
laser
scanners, and the
conversion of complex three-dimensional data into 3D computer models.
For further information,
contact Direct Dimensions by phone, 410-998-0880, fax, 410-998-0887,
email,
info@dirdim.com,
or visit
www.directdimensions.com.
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