A system which allows the computer to capture sketches
made by a mechanical designer is described. The system not
only recognizes basic features as they are sketched, but it
also reasons the spatial relationships between features and
builds a high level abstract representation (feature model)
of the artifact. The temporal nature of the capture, one
feature at a time, serves to form a feature graph that
allows for parametric design. The system is composed of
three subsystems: a two-dimensional freehand sketching
subsystem¹ , a three-dimensional features recognition
subsystem, and a spatial reasoning subsystem.
The freehand sketching subsystem takes the user's
input sketching actions and interprets them as simple, two-dimensional
geometric elements, such as line segments,
circles, and ellipses, etc. The features recognition
subsystem interprets the collection of two-dimensional
geometric elements to extract three-dimensional information
from them and creates high level abstract representations,
features. The spatial reasoning subsystem finds
relationships between a new feature and existing features
and integrates features to form a single part.
The work of the Design Capture System is aimed at
capturing sketches of a specific application domain:
injected molding plastic parts. Twenty injected molding
plastic parts were collected and analyzed to understand the
distribution of features.
Isometric sketching is selected as the basic
constructing method for the system. The processes of
freehand sketching and computer-aided drafting were studied
to find a better scheme for computer-aided sketching.
Conclusions are also presented.
¹The Freehand Sketching Subsystem was accomplished by
Roger Fang as a Master project in 1987 at the Department of
Mechanical Engineering, Oregon State University, Corvallis,
Oregon. / Graduation date: 1991
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37152 |
| Date | 16 July 1990 |
| Creators | Hwang, Teng-shang |
| Contributors | Ullman, David G. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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