Portuguese Meeting on Computer Graphics 2003
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Browsing Portuguese Meeting on Computer Graphics 2003 by Author "Fonseca, Manuel"
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Item Polygon Detection from a Set of Lines(The Eurographics Association, 2021) Jr., Alfredo Ferreira; Fonseca, Manuel; Jorge, Joaquim; Marcos, Adérito and Mendonça, Ana and Leitão, Miguel and Costa, António and Jorge, JoaquimDetecting polygons defined by a set of line segments in a plane is an important step in the analysis of vectorial drawings. This paper presents an approach that combines several algorithms to detect basic polygons from a set of arbitrary line segments. The resulting algorithm runs in polynomial time and space, with complexities of O((N + M)4) and O((N + M)2) respectively, where N is the number of line segments and M is the number of intersections between line segments. Our choice of algorithms was made to strike a good compromise between efficiency and ease of implementation. The result is a simple and efficient solution to detect polygons from lines.Item Task Analysis and Scenario-Based Design of Calligraphic Interfaces(The Eurographics Association, 2021) Dias, Filipe; Fonseca, Manuel; Jorge, Joaquim; Marcos, Adérito and Mendonça, Ana and Leitão, Miguel and Costa, António and Jorge, JoaquimThe great functionality of today's CAD systems enables the manufacturing of very complex models. Yet, great part of this power is unusable, early in the design process. As well, we have found two different approaches in two different car designers that surprisingly lead to the same long time in development. In this paper we identify the reasons for these problems, and propose a solution that bridges the different worlds of conceptual and geometric models, using the affordability of the calligraphic interface. Creating a prototype by drawing it allows impossible situations to be immediately identified and corrected, without further communication overheads, certifying that emotional drawing ideas correspond to the designer's intents.