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Parts Classification from Assembly Drawings

IP.com Disclosure Number: IPCOM000116165D
Original Publication Date: 1995-Aug-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Masuda, H: AUTHOR [+3]

Abstract

Disclosed is a method for identification of the parts from assembly drawings that are represented by the orthographic projections. The methods defines the Boolean equations which interprets the 3D cell decomposition model that is constructed from the projections. The variables in the equations are equivalent relations between the cells. By solving the Boolean equations, the cells are classified by equivalent class, and cells in a certain quotient set constructs an individual part.

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Parts Classification from Assembly Drawings

      Disclosed is a method for identification of the parts from
assembly drawings that are represented by the orthographic
projections.  The methods defines the Boolean equations which
interprets the 3D cell decomposition model that is constructed from
the projections.  The variables in the equations are equivalent
relations between the cells.  By solving the Boolean equations, the
cells are classified by equivalent class, and cells in a certain
quotient set constructs an individual part.

      Fig. 1 shows the example of assembly drawing.  Fig. 2 shows the
cell decomposition model constructed from the drawing.  The model
consists of 5 cells including the atmosphere cell (C0) which
surrounds the entire parts.

      The equivalent relation variable Rij represents that Ci and Cj
are in the same part.

      There are three conditions that formulate Boolean equations of
R: (1) visible edge condition, (2) non-manifold edge condition, and
(3)
transitive law condition.

      Fig. 3 shows the cells around the edge e1 in the Fig. 2.  The
three conditions described above forms the following equations.
  (1) R01 R23 = 0, R02 R13 = 0, ...
  (2) R03 &tilde.R01 &tilde.R02 = 0
  (3) R01 R13 R23 &tilde.R02 = 0, ...

      By solving the equations formulated with regarding to all the
edges, following solutions are obtained: (&tilde.R01 &tilde.R13
&tilde.R02 &tilde.R04 &tilde.R03), ..

      This means that...