Browse Prior Art Database

Solid Model Construction from Orthographic Views having "Simplified" Edges

IP.com Disclosure Number: IPCOM000116181D
Original Publication Date: 1995-Aug-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Inoue, K: AUTHOR [+3]

Abstract

Disclosed is a method for constructing a solid model from simplified orthographic views. The solid construction method in (1) expects perfect orthographic projections of a shape as an input. But in actual drawings line segments and arcs are also used in place of other type of curves just for simplicity. Such drawings are good enough or even better for actual purpose, but are not understandable by approaches like (1).

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Solid Model Construction from Orthographic Views having "Simplified"
Edges

      Disclosed is a method for constructing a solid model from
simplified orthographic views.  The solid construction method in (1)
expects perfect orthographic projections of a shape as an input.  But
in actual drawings line segments and arcs are also used in place of
other type of curves just for simplicity.  Such drawings are good
enough or even better for actual purpose, but are not understandable
by approaches like (1).

      Simplified edges are used mostly when 3D curve's projections
onto two views are either straight line or arc (elliptic arc), but
the third projection is not (i.e., intersection of two perpendicular
cylinders).  General assumption about simplified edge is that a
simplified edge is geometrically exact at each end, but curve
connecting is not accurate.

      In the early stage of a solid model construction, a wireframe
model is necessary.  Usually each 3D edge in a wireframe model is
generated on condition that three edges in different views are exact
projections of the 3D edge, that means three curves and six vertices
on drawings conform to the single 3D edge.  In proposed method, even
when they don't conform, a possible 3D edge is generated from two out
of three curves.  The third curve, different from the original, is
derived from the resultant 3D edge.

      Therefore, at maximum, three possible 3D edges are generated
from one combination.  The f...