authors 
Medjdoub, Benachir 
year 
1999 
title 
Interactive 2D ConstraintBased Geometric Construction System 
source 
Proceedings of the Eighth International Conference on Computer Aided Architectural Design Futures [ISBN 0792385365] Atlanta, 78 June 1999, pp. 197212 
summary 
This paper presents a 2D ConstraintBased Geometric Construction System where positioning and manipulating geometry is very precise. An unusually simple interface makes this system particularly interactive and easy to use. In our approach, the geometry types supported are: points, lines, circles, ellipses, circular arcs and bspline curves. All the fundamental topologic constraints, i.e. tangent, parallel, perpendicular, coincident and concentric, are provided. Metric constraints, i.e. dividing the shapes into equal parts or fixing the geometric parameters, are also provided. These constraints are automatically applied by the application in response to the implied intentions of the end user. Dynamic modifications of partially dimensioned models are supported, whereby the design is modified while enforcing the constraints. A graphconstructive approach is used to solve the model. As we are dealing with partial modifications, this resolution technique is quite sufficient, and makes our system stable and flexible. Our approach focuses highly on interactivity. Positioning a shape constrained to another is made directly through the graphic interface. Constraint relaxation is also done by direct manipulations. Modifications are made by dragging the geometry, or by typing into a numerical panel displaying the free shape parameters. Again, existing constraints are maintained as those numbers are applied. Well constrained and underconstrained problems are discussed. This approach was developed in Java, JDK 3.0.1 of SGI's Java software. 
keywords 
Sketching, Geometric Constraints, Interactivity, Geometric construction, Dynamic Modifications 
series 
CAAD Futures 
email 
Benachir.Medjdoub@nottingham.ac.uk 
full text 
file.pdf (1,595,416 bytes) 
references 
Contenttype: text/plain

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last changed 
2006/11/07 06:22 
