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Method for Understanding Drawing Attributes for 3D Models

IP.com Disclosure Number: IPCOM000113058D
Original Publication Date: 1994-Jul-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 6 page(s) / 148K

Publishing Venue

IBM

Related People

Masuda, H: AUTHOR [+3]

Abstract

This article describes a method for generating a solid model from orthographic views, and adding constraints and attributes to the solid model.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Method for Understanding Drawing Attributes for 3D Models

      This article describes a method for generating a solid model
from orthographic views, and adding constraints and attributes to the
solid model.

      Solid models are useful for design and process planing, but
most existing data are 2D drawings.  Solid models can be generated
from two or three orthographic views [*], but this technology
generates only geometric data, and discards constraints and
attributes such as dimensions, tolerances, or symbols for machining.
Since such constraints and attributes are indispensable for process
planning, they must be manually added to solid models in conventional
methods.

      This invention aims to extract attributes from orthographic
views, and to add them to solid models generated from orthographic
views.

      This invention consists of the following modules: a) the module
for extracting geometric data, constraints and attributes from
orthographic views, b) the module for keeping relationships between
orthographic views and the generated solid model, c) the module for
translating dimensions as parameters of solid models, d) the module
for translating attributes of drawings as attributes of topological
entities in solid models.  Fig. 1 shows the above process.

      a) The module for extracting the geometric data, constraints
and attributes from orthographic views.

      Module a) extracts geometric data from orthographic views.
Fig. 2 shows geometric data extracted from a view.  As shown in Fig.
2, extracted data are classified into Point, Line, Circle, or
Center-Point, and stored them in the database.

      Next, the system extracts dimensions among points and segments
in drawings.  Fig. 3 shows dimensions that can be extracted from
views.  lt c gt , which is a constraint between line lt a gt   and lt
a prime gt , means that the distance between segment e1 and e2 is 20.
lt k gt   means that the radius of the circle pointed by an arrow is
20.  Such dimensions are stored in the database as relationships
between points or segments.

      Finally, the system extracts dimensional tolerances,
geometrical tolerances, surface textures, note, and other attributes.
In Fig. 4, for example, max=0 and min=-0.1 shown by  lt p gt  can be
extracted as a dimensional tolerance.

      b) The module for keeping the relationship between orthographic
views and a solid model.

      In 2D-3D translation methods, such as [*], vertices and edges
of solid models are created using corresponding points or segments in
each view.  Next, pl...