Product category:
Rapid Prototyping
News Release from: 3D Scanners | Subject: ModelMaker
Edited by the Engineeringtalk Editorial
Team on 05 July 2002
Laser scanning speeds surface modelling
ModelMaker from 3D Scanners is speeding up the creation of surface models at DaimlerChrysler by providing highly dense, accurate point clouds from which to construct digital surfaces.
The use of ModelMaker from 3D Scanners is speeding up the creation of surface models at DaimlerChrysler by providing highly dense, accurate point clouds from which to construct digital surfaces The company's Vehicle Measurement Lab scans car bodies, interiors, and clay prototypes to support the design process
The resulting co-ordinate data are imported into a CAD system and converted into surfaces.
Previous scanning devices - a co-ordinate measuring machine (CMM) and a mechanical digitiser - captured relatively few co-ordinate locations, making the construction of surfaces very labour-intensive.
By switching to a laser scanner, the lab now captures millions of x-y-z co-ordinates quickly, giving designers a thorough definition of an object's shape and making the job of constructing surfaces go much faster.
Another advantage of the laser scanner is that it captures co-ordinate locations without touching the object.
This makes it possible to scan clay models without marking them, and to scan soft objects such as leather seats more accurately.
The Vehicle Measurement Lab's main role is to provide thorough, quantitative descriptions of competitors' vehicles, including width, height, wheelbase as well as the layout of the interior space, so designers can see how other manufacturers addressed certain market needs.
Donald Misson, Vehicle Measurement Lab supervisor, explained, "We get some design data from the organisations we belong to, but we've found that the most accurate way to evaluate competitors' vehicles is to measure them ourselves".
The lab also measures the clay models used by designers during the conceptual stage of vehicle development.
While DaimlerChrysler uses electronic Catia models as the masters for development of new vehicle designs, clay models are still used extensively, especially early in the design process.
Conceptual designs are modelled in Alias/Wavefront's industrial design software, Studio.
Clay models are then sculpted from the Studio models.
Designers physically fine-tune the clay models until they have the precise shape they want.
That shape must then be captured digitally for import into Catia.
The Lab's third role involves supporting DaimlerChrysler's racing efforts.
Wind tunnel testing is used extensively by the racing group to improve vehicle aerodynamics.
The lab measures the clay models used in the wind tunnel tests.
Similar to the design process for consumer vehicles, racing car designers refine clay models until they have the shape they want.
In this case, they are modifying the models in response to the wind tunnel results to improve aerodynamic performance.
The measurement lab captures the shape of the modified models so the data can be used in Catia.
"The advantage of the laser scanner is that it gives us a greater density of data", says Misson.
"Rather than cross-sections of an object we can provide complete surfaces, so there's much less time required to generate surface models in the CAD system".
For DaimlerChrysler's Vehicle Measurement Lab, a laser scanner is superior to both a CMM and a mechanical digitiser for capturing interior and exterior vehicle shapes.
The noncontact nature of the laser scanner eliminates problems that used to compromise the accuracy of the scanned data.
More importantly, it speeds the work of designers by giving them complete surface data with which to construct CAD surface models.
Since the lab has been using the laser scanner, the job of creating surface models in Catia has been transformed from a very labour-intensive process to an efficient, almost automatic routine.
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