Reverse Engineering is the honorable process of measuring a part or object and then creating a CAD model of the part/object that reflects how it was to be designed originally.  The most common way to conduct the measurement is through digital scanning.  So a firm that specializes in scanning, such as Direct Dimensions Inc. (DDI), of Baltimore, winds up being involved in many interesting reverse engineering projects.

Such a project was the re-creation of the original wood propellers from the 1903 Wright airplane that flew at Kitty Hawk, NC in 1903.  As part of a historical re-enactment, DDI measured, modeled, and reproduced the original Wright Brothers Airplane propellers.

This involved reviewing the original flight and plans, then laser scanning the existing propellers in a museum. Several other original propellers produced as late as 1912 were also measured at various museums. 

Laser scanning is the process of shining a structured laser light over the surface of an object to collect 3-dimensional data. The surface data is captured by a camera sensor mounted in the laser scanner, which records accurate dense 3D points in space. After the scanning is complete, points and a wireframe are prepared, the CAD model completed, and a model of the propeller rendered.  Finally, the new propellers are milled from solid mahogany.

Another aircraft project of quite a different nature involved reverse engineering the exterior surfaces of an F-15b fighter plane.  The objective of that project was to develop a solid model of the plane that then could be used for subsequent engineering analysis such as a computational fluid dynamics review of the craft.

Reverse engineering of the 1903 Wright propeller started with the original plans, then a careful scan, a 3D model of the propeller, and finally milling it from mahogany. 

The project started with an original F-15b aircraft.  Using a Faro laser scanner, DDI captured a point cloud scan of the entire aircraft.  The point cloud data were aligned, cleaned, and a complete solid model made of the aircraft.  With that model, a CFD analysis could be performed on the aircraft.

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Direct Dimensions Inc.
www.directdimensions.com

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