@article{cybenko:3dcad,
    author = {George Cybenko and Aditya Bhasin and Kurt D. Cohen},
    title = {Pattern Recognition of {3D CAD} Objects: Towards an Electronic
Yellow Pages of Mechanical Parts},
    journal = {Smart Engineering Systems Design},
    year = {1997},
    volume = {1},
    pages = {1--13},
    group = {agents},
    url = {http://agent.cs.dartmouth.edu/papers/cybenko:3dcad.ps.gz},
    keyword = {mobile agents, pattern recognition, information retrieval},
    abstract = {Industry estimates show that aggressive reuse of existing
inventory could reduce the delivered cost of large, complex manufactured
systems by as much as 20\%. In most cases these savings are not captured,
principally because the current technology to locate reusable designs and
inventory, which uses taxonomies and other artificial indices, is too
cumbersome. Furthermore, current systems do not address the design phase -
where opportunities for reuse first arise. This paper describes a
computer-based technology that will be an important step towards solving this
problem. \par For mechanical parts, the modern design phase starts with
computer aided design (CAD) packages. Given a prototype design of a solid
object, the design engineer should be able to determine whether the part
under consideration is already designed or in manufacture. Our system does
this by using physical shape as a direct index to existing designs and
manufactured components, eliminating time-consuming and error-prone searches
of the taxonomy. Other applications of this technology include identification
of warehoused parts according to scanned shape and efficient management of
3-dimensional objects in computer animation and virtual reality systems. \par
Our system takes a standard digital representation of a solid object, such as
in IGES form, and produces a surface triangular mesh representing the
boundary of the object. The surface mesh allows a voxel approximation
representation of the solid which is computed by flood filling. Zeroth, first
and second order geometrical moments are used to normalize the orientation of
the solid. Then a variety of volumetric invariants are computed and used as
features. These features determine a hash function which maps similar shapes
to closely related feature vectors. Nearby feature vectors identify a small
subset of objects which are compared using symmetric differencing on a voxel
by voxel basis. This voxel symmetric difference gives a rank ordering of
similarity between 3-dimensional shapes in the database and the object under
consideration. Using this small subset of like-shaped objects, the design
engineer can browse a reasonable subset of parts from the complete database.
\par The described research has significant applications in industries which
seek to reuse existing designs and inventory thereby reducing manufacturing
costs. Applications in aerospace, automobile and machine tool industries are
most promising and urgent. We expect that this research will lead to the
commercial development of software that will enhance existing CAD and
database systems.},
}