SBM04: Sketch Based Interfaces and Modeling 2004

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https://diglib.eg.org/handle/10.2312/422

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Constraint Stroke-Based Oversketching for 3D Curves.
(The Eurographics Association, 2004) Fleisch, Timo; Rechel, Florian; Santos, Pedro; Stork, André; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
In this paper we present an extended approach for stroke oversketching. The stroke oversketching technique changes a curve by redrawing parts of it. Finding the part to replace and smoothing the transition is done automatically. Our extension to oversketching constraints the change of the curve to one single side profile leaving the other side profiles of the curve unchanged. Additionally we present the advantage of using this approach in car design following the classic four-side-view drawing approach.
Process Improvement Impacts on the Styling Workflow of an Industrial Design Company
(The Eurographics Association, 2004) Barone, Mirko; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
The renovation of the process represents a must for an industrial company involved in the design field. The process is moving from an entirely manual to a digital workflow, so much that sometimes users find many difficulties in the approach to the new tools. In particular, analyzing the methodologies of work it is easy to find out a big gap between the styling phase and the creation of the 3D model. One question to investigate is how much the style of a model starts to be influenced by the technological tools designed to construct it. Starting from an accurate study of the Italdesign-Giugiaro process we present the efforts made to overcome the issues and define a more designer-oriented workflow, with the aim of the European Research Project SmartSketches.
A Cameraphone-Based Approach for the Generation of 3D Models from Paper Sketches .
(The Eurographics Association, 2004) Farrugia, Philip J.; Borg, Jonathan C.; Camilleri, Kenneth P.; Spiteri, Christopher; Bartolo, Alexandra; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
Due to the advantages it offers, a sketch-based user-interface (UI) has been utilised in various domains, such as 3D modelling, 'graphical user-interface' design, 3D animation of cartoon characters, etc. However, its benefits have not yet been adequately exploited with those of a mobile phone, despite that the latter is nowadays a widely used wireless handheld device for mobile communication. Given this scenario, this paper discloses a novel approach of using a paper sketch-based UI, which combines the benefits of paper sketching and those of a cameraphone (a mobile phone with an integrated camera), in the domain of early form design modelling. More specifically, the framework disclosed and evaluated in this paper, enables users to remotely obtain visual representations of 3D geometric models from freehand sketches by combining the portability of paper with that of cameraphones. Based on this framework, a prototype tool has been implemented and evaluated. Despite the limitations of the current prototype tool, the evaluation results of the framework s underlying concepts and of the prototype tool collectively indicate that the idea disclosed in this paper contributes in providing users with a mobile sketch-based interface, which can also be used in other domains, beyond early form design modelling.
Adaptation of Brensen s Thresholding Algorithm for Sketched Line Drawings
(The Eurographics Association, 2004) Bartolo, Alexandra; Camilleri, Kenneth P.; Farrugia, Philip J.; Borg, Jonathan C.; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
Image binarisation is one of the first image processing techniques within a sketched line drawing interpretation system. In order to achieve an automated system, it is necessary to have a single algorithmwhich may be used for all image types. This is difficult to obtain if the parameters required by an algorithm are set manually, however, the adaptive evaluation of parameters form image properties is a step towards this goal. This paper discusses the methods by which the parameters required for Brensen s Algorithm may be evaluated adaptively form the image properties.
A Multi-Agent System for the Interpretation of Architectural Sketches
(The Eurographics Association, 2004) Juchmes, Roland; Leclercq, Pierre; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
Architects widely resort to sketch during their early phase of design, because sketching appears to be the most adapted mean to express and to manipulate creative ideas. In order to assist the designers during this inventive phase of work we have developed EsQUIsE-SMA, an on-line system for capturing and interpreting architectural sketches. This prototype is based on a MAS, MultiAgent System, which enables real time management of recognition scenarios. This paper describes the basic mechanisms involved by EsQUIsE-SMA to interpret free hand architectural drawings : the sketch as an evolutive environment, the agent types for stroke analysis and the collaboration modes between agents. The conclusions deduce the salient characteristics for a MAS dedicated to sketch analysis.
A Sketch-Based Interface for Collaborative Design .
(The Eurographics Association, 2004) Fan, Zhe; Chi, Ma; Kaufman, Arie; Oliveira, Manuel M.; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
We present an interface for collaborative conceptual design that combines sketch elements, direct manipulation of 3D objects and non-photorealistic rendering. Such a combination results in a simple and intuitive 2D-sketch-to- 3D modeling system suitable for novice users. It allows users potentially located in geographically distant areas to cooperate by sketching, exploring and modifying their ideas interactively, with immediate visual feedback. Our system prototype supports several modeling primitives and can be extended to handle user-defined objects. Potential applications of our system include early stages of urban and landscape design, rapid prototype of virtual environments, animation, education and recreational use.
Sketching Garments for Virtual Characters .
(The Eurographics Association, 2004) Turquin, Emmanuel; Cani, Marie-Paule; Hughes, John F.; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
We present a method for simply and interactively creating basic garments for dressing virtual characters in applications like video games. The user draws an outline of the front or back of the garment, and the system makes reasonable geometric inferences about the overall shape of the garment (ignoring constraints arising from physics and from the material of the garment). Thus both the garment s shape and the way the character is wearing it are determined at once. We use the distance from the 2D garment silhouette to the character model to infer the variations of the distance between the remainder of the garment and the character in 3D. The garment surface is generated from the silhouette and border lines and this varying distance information, thanks to a data-structure that stores the distance field to the character s body. This method is integrated in an interactive system in which the user sketches the garment over the 3D model of the character. Our results show that the system can be used to create both standard clothes (skirts, shirts) and other garments that may be worn in a variety of ways (scarves, panchos). Key words; Sketch-based interfaces, virtual garment, shape modelling.
A Two-Stage Approach for Interpreting Line Drawings of Curved Objects
(The Eurographics Association, 2004) Varley, P. A. C.; Takahashi, Y.; Mitani, J.; Suzuki, H.; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
We describe a two-stage approach for interpreting line drawings of curved objects. In the first stage, the user enters a natu-ral line drawing of a polyhedral template; this is automatically interpreted as the corresponding polyhedral object. In the second stage, the user enters freehand curves; by relating these to the template, a curved object can be constructed
Towards 3DModeling using Sketches and Retrieval
(The Eurographics Association, 2004) Fonseca, Manuel J.; Ferreira, Alfredo; Jorge, Joaquim A.; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
Retrieving 2D and 3D drawings by content is not an easy task. Automatic feature extraction, indexing and matching are some of the problems raised by these approaches. We have developed a generic method to classify, index and retrieve drawings using sketches, based on spatial relationships, shape geometry and high-dimensional indexing mechanisms. This approach has been applied with success to retrieving clip-art and complex technical drawings from large databases. In this paper we give a brief overview of our approach for content-based retrieval and describe two prototypes for retrieving 2D drawings. We also present a preliminary study that combines retrieval of 3D objects and expectation lists to define a new interaction paradigm based on suggestions. 3D objects are described using their face and edge graphs, which are then mapped into multidimensional descriptors through graph spectra. Preliminary results show that the combination of these two descriptors (faces and edges) provide a good novel method to describe and retrieve similar 3D objects. Finally, rather than developing a system to specify and display 3D queries and results, we integrated the retrieval system into a 3D modeling tool, through the use of expectation lists. This way, results from the query are presented as suggestions to the user, in what constitutes a new interaction paradigm, which is more flexible then present approaches.
From raw 3D-Sketches to exact CAD product models Concept for an assistant-system
(The Eurographics Association, 2004) Diehl, Holger; Müller, Franz; Lindemann, Udo; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
As we try to develop new 3D-Sketching devices we come across the problem of how to transfer 3D-Sketches into exact product models to gain an integrated design system. There are some promising approaches for the retrieving of 3D-geometries out of 2D-Sketches, but nearly none supports the concretization of 3D-Sketches. We are developing an intelligent assistant that supports the designer in the task of concretization. Our higher level goal is a system that uses a cad-kernel and supports the designer from the early stages of sketching up to the modelling of exact product representations.
3D Sketching with Fully Free Form Deformation Features (d-F4) for Aesthetic Design
(The Eurographics Association, 2004) Cheutet, V.; Catalano, C. E.; Pernot, J. P.; Falcidieno, B.; Giannini, F.; Leon, C.; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
This paper addresses the designers activity and in particular the way designers express an object shape in 2D sketches through character lines. The tools currently available in commercial CAS/CAD systems to manipulate the digital models are still not sufficiently suited to support design. In this paper, we introduce the so-called Fully Free Form Deformation Features (d-F4), able to take into account the curve-oriented stylists way of working. Both the advantages of a free form surfaces deformation method and a feature-based approach are merged to define highlevel modelling entities allowing for a direct manipulation of surfaces through a restricted number of intuitive parameters. In addition, a d-F4 classification is proposed to permit a fast access to the desired shape according to its semantics. The proposed approach is illustrated with some examples.
Can Machines Interpret Line Drawings?
(The Eurographics Association, 2004) Varley, P. A. C.; Suzuki, H.; Martin, R. R.; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
Engineering design would be easier if a computer could interpret initial concept drawings. We outline an approach for automated interpretation of line drawings of polyhedra, and summarise what is already possible, what developments can be expected in the near future, and which areas remain problematic. We illustrate this with particular reference to our own system, RIBALD, summarising the published state of the art, and discussing recent unpublished improvements to RIBALD. In general, successful interpretation depends on two factors: the number of lines, and whether or not the drawing can be classified as a member of special shape class (e.g. an extrusion or normalon). The state-of-the-art achieves correct interpretation of extrusions of any size and most normalons of 20 30 lines, but drawings of only 10 20 lines can be problematic for unclassified objects.Despite successes, there are caseswhere the desired interpretation is obvious to a human but cannot be determined by currently-available algorithms. We give examples both of our successes and of typical caseswhere human skill cannot be replicated.
Cascading Recognizers for Ambiguous Calligraphic Interaction .
(The Eurographics Association, 2004) Pereira, João P.; Branco, Vasco A.; Jorge, Joaquim A.; Silva, Nelson F.; Cardoso, Tiago D.; Ferreira, F. Nunes; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
Throughout the last decade many approaches have been made to the problem of developing CAD systems that are usable in the early stages of product ideation. Although most of these approaches rely on some kind of drawing paradigm and on the paper-and-pencil metaphor, only a few of them deal with the ambiguity that is inherent to natural languages in general and to sketching in particular. Also the paper-and-pencil metaphor has not in most cases been fully accomplished, since many gesture-based interfaces resort to secondary buttons and modifier keys in order to make command strokes easier to differentiate from their geometry instantiating counterparts. In this paper we describe the architecture of GIDeS++, a sketch-based 3D modeling system that approaches these problems in three different ways: by dealing with ambiguity and exploring it to the user s benefit; by reducing the command set and thus minimizing the cognitive load on the user; and by cascading different types of gesture recognizers, which allows interaction to resort only to the button located on the tip of an electronic stylus.
On the Evolution of Geometrical Reconstruction as a Core Technology to Sketch-Based Modeling
(The Eurographics Association, 2004) Company, Pedro; Piquer, Ana; Contero, Manuel; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
In this work, the background and evolution of three-dimensional reconstruction of line drawing over the last thirty years is discussed. A new general taxonomy is proposed to describe and discuss the historical evolution of geometrical reconstruction and its challenges. The evolution of geometrical reconstruction from recovering know-how stored in engineering drawings to sketch-based modeling for helping in the first steps of conceptual design purposes, and the current challenges of geometrical reconstruction are also discussed.
Pen Stroke Extraction and Refinement using Learned Models
(The Eurographics Association, 2004) Simhon, Saul; Dudek, Gregory; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
This paper presents a smart interface that automatically extracts and refines pen strokes from images of hand drawn sketches. The interface allows users to digitize hand-drawn material such sketches of flowcharts, cartoons or other pen based drawings and automatically isolate and refine the individual strokes making up the sketch. First, we present a method for extracting pen strokes based on learned constraints on curves. The approach consists of using a training set that shows good examples of curves and how a user would draw them. Given an image of a hand-drawn sketch, the system selects the pen stroke that is most statistically consistent with the examples in the training set and ranks the others based on their likelihood. Users can keep the selected candidate or they may scroll through the other top candidates to select a preferred solution. Second, we present an overview of our refinement procedure and its application on the extracted pen strokes. Using the same database of examples, the extracted pen stroke is refined to make it 'look' more like those in the database.
Pen-to-mime: A Pen-Based Interface for Interactive Control of A Human Figure
(The Eurographics Association, 2004) Oshita, Masaki; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
This paper presents a pen-based intuitive interface to control a virtual human figure interactively. Recent commercial pen devices can detect not only the pen positions but also the pressure and tilt of the pen. We utilize such information to make a human figure perform various types of motions in response to the pen movements manipulated by the user. A figure walks, runs, turns and steps along the trajectory and speed of the pen. The figure also bends, stretches and tilts in response to the tilt of the pen. Moreover, it ducks and jumps in response to the pen pressure. Using this interface, the user controls a virtual human figure intuitively as if he or she were holding a virtual puppet and playing with it. In addition to the interface design, this paper describes a motion generation engine to produce various motions based on the parameters that are given by the pen interface. We take a motion blending approach and construct motion blending modules with a set of small number of motion capture data for each type of motions. Finally, we discuss about the effectiveness and limitations of the interface based on some preliminary experiments.
Sketching in Early Conceptual Phases of Product Design: Guidelines and Tools
(The Eurographics Association, 2004) Ponn, Josef; Lindemann, Udo; Diehl, Holger; Müller, Franz; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
The early phases of product development play a significant role for the success of a product and the prevention of time and money consuming changes in late phases. This paper describes a new methodological approach for the genereration of principle solutions in the form of sketches in early phases of product development. A guideline has been developed for a target-oriented and efficient progression from working principles to principle solutions. In particular, the linkage between physical effects and form parameters (geometry, materials etc.) has been investigated. A computer system including physical effects as features which can be used for the generation of digital principle sketches is described as a vision. Such a system offers the potential of facilitating routine work and supporting the engineer in defining solution concepts at early stages of product design.
Spatial Recognition and Grouping of Text and Graphics
(The Eurographics Association, 2004) Shilman, Michael; Viola, Paul; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
We present a framework for simultaneous grouping and recognition of shapes and symbols in free-form ink diagrams. The approach is completely spatial, that is it does not require any ordering on the strokes. It also does not place any constraint on the relative placement of the shapes or symbols. Initially each of the strokes on the page is linked in a proximity graph. A discriminative classifier is used to classify connected subgraphs as either making up one of the known symbols or perhaps as an invalid combination of strokes (e.g. including strokes from two different symbols). This classifier combines the rendered image of the strokes with stroke features such as curvature and endpoints. A small subset of very efficient features is selected, yielding an extremely fast classifier. An A-star search algorithm over connected subsets of the proximity graph is used to simultaneously find the optimal segmentation and recognition of all the strokes on the page. Experiments demonstrate that the system can achieve 97% segmentation/recognition accuracy on a cross-validated shape dataset from 19 different writers.
Epipolar Methods for Multi-View Sketching .
(The Eurographics Association, 2004) Karpenko, Olga; Hughes, John F.; Raskar, Ramesh; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
Single view sketch-based modelers like SKETCH and Teddy can be powerful tools, but sometimes their inferences are inadequate: in Teddy, for example, if one draws an animal shape, the centerline of the tail will always lie in a plane rather than being curved in 3D. In these cases, multiple-view sketching seems like a reasonable solution: a single sketch gets viewed from a new direction, in which further sketching modifies the shape in a way that's consistent with the original sketch. This paper describes a testbed implementation of such a multi-view sketching approach, based on epipolar lines, which is used for multi-view editing of the "backbone" lines for generalized cylinders. The method works well on many objects, particularly those where precise geometry is not important, but general shape and form must be richer than those with planar symmetry, but is difficult to use in other cases; some difficulties may be related to implementation choices, but we believe that the main problems are tied to the underlying approach, which while mathematically sound proves to be cognitively difficult. We analyze the limitations, and suggest approaches for future work in multi-view sketch-based modeling. Key words: Sketch-based interfaces, shape modeling.
Relief: A Modeling by Drawing Tool
(The Eurographics Association, 2004) Bourguignon, David; Chaine, Raphaelle; Cani, Marie-Paule; Drettakis, George; Joaquim Armando Pires Jorge and Eric Galin and John F. Hughes
This paper presents a modeling system which takes advantage of two-dimensional drawing knowledge to design three-dimensional free-form shapes. A set of mouse or tablet strokes is interpreted by the system as defining both a two-dimensional shape boundary and a displacement map. This information is used for pushing or pulling vertices of existing surfaces, or for creating vertices of new surface patches. To relieve the burden of 3D manipulation from the user, patches are automatically positioned in space. The iterative design process alternates a modeling by drawing sequence and a viewpoint change. To stay as close as possible to the traditional drawing experience, the system imposes the minimum number of constraints on the topology of either the strokes set or the resulting surface.

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