From on-line sketching to 2D and 3D geometry: A fuzzy knowledge based system

The paper describes the development of a fuzzy knowledge based prototype system for conceptual design. This real time system is designed to infer user’s sketching intentions, to segment sketched input and generate corresponding geometric primitives: straight lines, circles, arcs, ellipses, elliptical arcs, and B-spline curves. Topology information (connectivity, unitary constraints and pairwise constraints) is received dynamically from 2D sketched input and primitives. From the 2D topology information, a more accurate 2D geometry can be built up by applying a 2D geometric constraint solver. Subsequently, 3D geometry can be received feature by feature incrementally. Each feature can be recognised by inference knowledge in terms of matching its 2D primitive configurations and connection relationships. The system accepts not only sketched input, working as an automatic design tools, but also accepts user’s interactive input of both 2D primitives and special positional 3D primitives. This makes it easy and friendly to use. The system has been tested with a number of sketched inputs of 2D and 3D geometry

Algorithmic Perception of Vertices in Sketched Drawings of Polyhedral Shapes

In this article, visual perception principles were used to build an artificial perception model aimed at developing an algorithm for detecting junctions in line drawings of polyhedral objects that are vectorized from hand-drawn sketches. The detection is performed in two dimensions (2D), before any 3D model is available and minimal information about the shape depicted by the sketch is used. The goal of this approach is to not only detect junctions in careful sketches created by skilled engineers and designers but also detect junctions when skilled people draw casually to quickly convey rough ideas. Current approaches for extracting junctions from digital images are mostly incomplete, as they simply merge endpoints that are near each other, thus ignoring the fact that different vertices may be represented by different (but close) junctions and that the endpoints of lines that depict edges that share a common vertex may not necessarily be close to each other, particularly in quickly sketched drawings. We describe and validate a new algorithm that uses these perceptual findings to merge tips of line segments into 2D junctions that are assumed to depict 3D vertices

Exploring perceptions and attitudes towards teaching and learning manual technical drawing in a digital age

This paper examines the place of manual technical drawing in the 21st century by discussing the perceived value and relevance of teaching school students how to draw using traditional instruments, in a world of computer aided drafting (CAD). Views were obtained through an e-survey, questionnaires and structured interviews. The sample groups represent professional CAD users (e.g. engineers, architects); university lecturers; Technology Education teachers and student teachers; and school students taking Scottish Qualification Authority (SQA) Graphic Communication courses. An analysis of these personal views and attitudes indicates some common values between the various groups canvassed of what instruction in traditional manual technical drafting contributes towards learning. Themes emerge such as problem solving, visualisation, accuracy, co-ordination, use of standard conventions, personal discipline and artistry. In contrast to the assumptions of Prensky's thesis (2001a&b) of digital natives, the study reported in this paper indicate that the school students apparently appreciate the experience of traditional drafting. In conclusion, the paper illustrates the perceived value of such learning in terms of transferable skills, personal achievement and enjoyment

Tolerance Zone-Based Grouping Method for Online Multiple Overtracing Freehand Sketches

Multiple overtracing strokes are common drawing behaviors in freehand sketching; that is, additional strokes are often drawn repeatedly over the existing ones to add more details. This paper proposes a method based on stroke-tolerance zones to group multiple overtraced strokes which are drawn to express a 2D primitive, aiming to convert online freehand sketches into 2D line drawings, which is a base for further 3D reconstruction. Firstly, after the user inputs a new stroke, a tolerance zone around the stroke is constructed by reference to its polygonal approximation points obtained from the stroke preprocessing. Then, the input strokes are divided into stroke groups, each representing a primitive through the stroke grouping process based on the overtraced ratio of two strokes. At last, each stroke group is fitted into one or more 2D geometric primitives including line segments, polylines, ellipses, and arcs. The proposed method groups two strokes together based on their screen-space proximity directly instead of classifying and fitting them firstly, so that it can group strokes of arbitrary shapes. A sketch-recognition prototype system has been implemented to test the effectiveness of the proposed method. The results showed that the proposed method could support online multiple overtracing freehand sketching with no limitation on drawing sequence, but it only deals with strokes with relatively high overtraced ratio

A framework of web-based conceptual design

A web-based conceptual design prototype system is presented. The system consists of four parts which interpret on-line sketches as 2D and 3D geometry, extract 3D hierarchical configurations, allow editing of component behaviours, and produce VRML-based behavioural simulations for design verification and web-based application. In the first part, on-line freehand sketched input is interpreted as 2D and 3D geometry, which geometrically represents conceptual design. The system then infers 3D configuration by analysing 3D modelling history. The configuration is described by a parent–child hierarchical relationship and relative positions between two geometric components. The positioning information is computed with respect to the VRML97 specification. In order to verify the conceptual design of a product, the behaviours can be specified interactively on different components. Finally, the system creates VRML97 formatted files for behavioural simulation and collaborative design application over the Internet. The paper gives examples of web-based applications. This work forms a part of a research project into the design and establishing of modular machines for automation manufacture. A consortium of leading automotive companies is collaborating on the research project

Uključivanje 3D modeliranja tijela u kolegij inženjerske grafike

The increasing use of solid modelling has had considerable impact on changes in the design process, which has resulted in a stronger relation between design and engineering graphics. These attempts can be followed shifting from modest changes, by inserting 2D and 3D CAD models into introductory engineering graphics course to the approach of implementing parametric, feature-based and constraint-based modelling, which have led towards the development of 3D model centred engineering curriculum. This paper presents some characteristic approaches chosen from numerous contributions dealing with the introduction of new topics and technology in engineering graphics education, as well as the example of 3D model- centred engineering curriculum. A review of topics that are the most common proposal for an introductory engineering graphics course are extracted, regardless of different approaches that should accomplish the link between 3D modelling, engineering design and applications. A short description of engineering graphics courses and the topics covered at the University of Rijeka, Faculty of Engineering, as a result of revision that has emphasized 3D modelling and its role in the concurrent engineering design process is also presented.Na promjene u procesu konstruiranja znatno je utjecala povećana upo- raba modeliranja tijela, što je rezultiralo snažnijim odnosom između kon- struiranja i inženjerske grafike. Mogu se pratiti nastojanja, od stidljivih promjena uključivanjem 2D i 3D modela u uvodni kolegij inženjerske grafike, do pristupa upotpunjavanja parametarskim modeliranjem na os- novi značajke i ograničenja, što dovodi do razvitka inženjerskog nastavnog programa s 3D modelom u središtu. Ovaj rad predstavlja neke karakteristične pristupe izabrane iz brojnih doprinosa koji obrađuju uvođenje novih tema i tehnologija u obrazovanje inženjerske grafike, kao i primjer inženjerskog nastavnog programa s 3D modelom u središtu. Izdvojen je pregled tema koje su najčešći prijedlog za uvodni kolegij inženjerske grafike, bez obzira na različite pristupe koji trebaju ostvariti vezu između 3D modeliranja, inženjerskog konstruiranja i aplikacija. Također je predstavljen kratki opis kolegija inženjerske grafike i obuhvaćenih tema na Tehničkom fakultetu u Rijeci, kao rezultat dorada koje daju naglasak na 3D modeliranje i njegovu ulogu u procesu istodobnog inženjerskog konstruiranja

IDATER online conference: graphicacy and modelling 2010

IDATER online conference: graphicacy and modelling 201

Old School Catalog 1916-17, The Department of Engineering

https://scholar.valpo.edu/oldschoolcatalogs/1106/thumbnail.jp