SBM: Sketch Based Interfaces and Modeling

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2D Sketch Based Recognition of 3D freeform Shape by Using the RBF Neural Network
(The Eurographics Association, 2005) Qin, S. F.; Sun, Guangmin; Wright, D. K.; Lim, S.; Khan, U.; Mao, C.; Joaquim Armando Pires Jorge and Takeo Igarashi
This paper presents a novel free-form surface recognition method from 2D freehand sketching. The approach is based on the Radial basis function (RBF), an artificial intelligence technique. A simple three-layered network has been designed and constructed. After training and testing with two types of surfaces (four sided boundary surfaces and four close section surfaces), it has been shown that the method is useful in freeform surface recognition. The testing results are very satisfactory.
3D Geological Modeling using Sketches and Annotations from Geologic Maps
(ACM, 2014) Amorim, Ronan; Brazil, Emilio Vital; Samavati, Faramarz; Sousa, Mario Costa; Metin Sezgin
Constructing 3D geological models is a fundamental task in oil/gas exploration and production. A critical stage in the existing 3D geological modeling workflow is moving from a geological interpretation (usually 2D) to a 3D geological model. The construction of 3D geological models can be a cumbersome task mainly because of the models' complexity, and inconsistencies between the interpretation and modeling tasks. To narrow the gap between interpretation and modeling tasks, we propose a sketched based approach. Our main goal is to mimic how domain experts interpret geological structures and allow the creation of models directly from the interpretation task, therefore avoiding the drawbacks of a separate modeling stage. Our sketch-based modeler is based on standard annotations of 2D geological maps and on geologists' interpretation sketches. Specific geological rules and constraints are applied and evaluated during the sketch-based modeling process to guarantee the construction of a valid 3D geologic model.
3D Geological Modeling using Sketches and Annotations from Geologic Maps
(ACM, 2014) Amorim, Ronan; Brazil, Emilio Vital; Samavati, Faramarz; Sousa, Mario Costa; Metin Sezgin
Constructing 3D geological models is a fundamental task in oil/gas exploration and production. A critical stage in the existing 3D geological modeling workflow is moving from a geological interpretation (usually 2D) to a 3D geological model. The construction of 3D geological models can be a cumbersome task mainly because of the models' complexity, and inconsistencies between the interpretation and modeling tasks. To narrow the gap between interpretation and modeling tasks, we propose a sketched based approach. Our main goal is to mimic how domain experts interpret geological structures and allow the creation of models directly from the interpretation task, therefore avoiding the drawbacks of a separate modeling stage. Our sketch-based modeler is based on standard annotations of 2D geological maps and on geologists' interpretation sketches. Specific geological rules and constraints are applied and evaluated during the sketch-based modeling process to guarantee the construction of a valid 3D geologic model.
3D Modeling with a Symmetric Sketch
(The Eurographics Association, 2011) Öztireli, A. C.; Uyumaz, U.; Popa, T.; Sheffer, A.; Gross, M.; Tracy Hammond and Andy Nealen
We propose a method that allows geometric operations such as view change, deformation, simulation, or symmetrization on a single off-line sketch via a proxy geometry reconstructed directly from the sketch. The reconstruction captures the overall shape of the object depicted by making use of the global relationships of the curvesand the assumption that the sketched object is bilaterally symmetric. After cleaning the sketch and extracting the curves, topological and geometric properties of a set of identified points are used to derive robust correspondence and pairwise constraints. These constraints are considered all at once in a spectral algorithm to get the optimummatching of the curves. Depths of points on the matched curves are extracted by utilizing the symmetry assumption. They are then used to reconstruct a smooth geometry. The whole process is automatic except for a few seconds of user interaction.
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.
3D6B Editor: Projective 3D Sketching with Line-Based Rendering
(The Eurographics Association, 2005) Kallio, Kiia; Joaquim Armando Pires Jorge and Takeo Igarashi
In this work, a system for 3D sketching is presented. Instead of trying to process 3D data as geometric models constructed of surfaces or solids, the data is stored as 3D lines, preserving their form exactly as entered by the user. The 3D input of the system works by projecting 2D input from a single viewpoint to a grid surface that can be manipulated in real time. This enables creation of sketches with complex non-planar 3D strokes while still retaining the essence of pen and paper based sketching.
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.
Adding Dynamics to Sketch-based Character Animations
(The Eurographics Association, 2015) Guay, Martin; Ronfard, Rémi; Gleicher, Michael; Cani, Marie-Paule; Ergun Akleman
Cartoonists and animators often use lines of action to emphasize dynamics in character poses. In this paper, we propose a physically-based model to simulate the line of action's motion, leading to rich motion from simple drawings. Our proposed method is decomposed into three steps. Based on user-provided strokes, we forward simulate 2D elastic motion. To ensure continuity across keyframes, we re-target the forward simulations to the drawn strokes. Finally, we synthesize a 3D character motion matching the dynamic line. The fact that the line can move freely like an elastic band raises new questions about its relationship to the body over time. The line may move faster and leave body parts behind, or the line may slide slowly towards other body parts for support. We conjecture that the artist seeks to maximize the filling of the line (with the character's body)-while respecting basic realism constraints such as balance. Based on these insights, we provide a method that synthesizes 3D character motion, given discontinuously constrained body parts that are specified by the user at key moments.
Addressing Class Distribution Issues of the Drawing vs Writing Classification in an Ink Stroke Sequence
(The Eurographics Association, 2007) Wang, Xin; Biswas, Manoj; Raghupathy, Sashi; Michiel van de Panne and Eric Saund
Complicated by temporal correlations among the strokes and varying distributions of the underlying classes, the drawing/writing classification of ink strokes in a digital ink file poses interesting challenges. In this paper, we present our efforts in addressing some of the issues. First, we describe how we adjust the outputs of the neural network to a priori probabilities of new observations to produce more accurate estimates of the posterior probabilities. Second, we describe how to adapt the parameters of the HMM to new data sets. Albeit the fact that the emission probabilities of the HMM are computed indirectly from the outputs of the neural network, our modified Baum-Welch algorithm still finds the correct estimates for the HMM's parameters. We also present experimental results of our new algorithms on 6 real world data sets. The results show that our methods increase the F Measures of both the drawing and the writing classes on the more ''drawing intensive'' data sets which have stronger temporal correlations. But they do not perform well on the more ''writing intensive'' data sets.
AlgoSketch: Algorithm Sketching and Interactive Computation
(The Eurographics Association, 2008) Li, Chuanjun; Miller, Timothy S.; Zeleznik, Robert C.; Jr., Joseph J. LaViola; Christine Alvarado and Marie-Paule Cani
We present AlgoSketch, a pen-based algorithm sketching prototype with supporting interactive computation. AlgoSketch lets users fluidly enter and edit 2D handwritten mathematical expressions in the form of pseudocode-like descriptions to support the algorithm design and development process. By utilizing a novel 2D algorithmic description language and a pen-based interface, AlgoSketch users need not work with traditional, yet complex 1D programming languages in the early parts of algorithm development. In this paper, we present the details behind AlgoSketch including the design of our 2D algorithmic description language, support for iteration and flow of control constructs and a simple debugging trace tool. We also provide some examples of how AlgoSketch might be used in the context of image analysis and number-theoretic calculation problems found. Based on preliminary user feedback, we believe AlgoSketch has the potential to be used to design and test new algorithms before more efficient code is implemented. In addition, it can support users who may not be familiar with any advanced programming languages.
Applying Scenarios in User-Centred Design to Develop a Sketching Interface for Human Modelling and Animation
(The Eurographics Association, 2006) Mao, Chen; Qin, Seng Feng; Wright, David K.; Peng, Jun; Thomas Stahovich and Mario Costa Sousa
This paper presents our user and usability studies for applying scenarios in user-centred design to develop a sketching interface for virtual human modelling and animation. In this approach, we utilise the User Centred System Design (UCSD) strategy and spiral lifecycles to ensure system usability and functionalities. A series of usability techniques were employed. After the initial conceptual design, a preliminary user study (including questionnaires and sketching observations) was undertaken to establish the formal interface design. Second, an informal user test was conducted on the first prototype: a sketch-based 3D stick figure animation interface . Finally, a formal user evaluation (including performance tests, sketching observations, and interviews) was carried out on the latest version: a sketch-based virtual human builder . During this iterative process, various paper-based and electronic-based sketching scenarios were created, which were acted-out by users to help designers evoke and verify design ideas, identify users needs, and test the prototype interfaces in real contexts. Benefiting from applying the UCSD strategy and scenario-based design to develop a natural and supportive sketching interface, our investigation can be a useful instantiation for the design of other sketching interfaces where these techniques have not been widely acknowledged and utilised in the past.
Assisted Multitouch Image-Based Reconstruction
(The Eurographics Association, 2010) Bauer, Frank; Stamminger, Marc; Marc Alexa and Ellen Yi-Luen Do
We present an image-based reconstruction approach for mobile, multitouch enabled devices. A novel scene description based on a multi-agent system is used to allow a real-time reconstruction workflow even on devices with relatively low processing speeds. Using the built in camera along with data from an accelerometer, compass and GPS module allows us to easily add new camera objects to our reconstruction world with an initial estimation for position and orientation. Our multi-agent scene description proved to be flexible enough to perform modelling tasks beyond image-based reconstruction using multitouch gestures only.
Automated Labeling of Ink Stroke Data
(The Eurographics Association, 2012) Zhen, Jacky (Shunjie); Blagojevic, Rachel; Plimmer, Beryl; Karan Singh and Levent Burak Kara
Labeled ink stroke data is essential to the development and evaluation of sketch recognizers. Manually labeling strokes is a tedious, time-consuming, and error prone task; and very few tools are available to facilitate this. We propose a new and intuitive method of automatic labeling for single stroke primitives. This involves building a recognizer from a partially labeled dataset. This recognizer is then used to identify and automatically label the remaining data, therefore reducing the amount of manual labeling required by researchers. An evaluation comparing manual labeling against our new auto labeling method shows that users are able to label significantly faster and produce less errors using auto labeling. Furthermore, users found auto labeling easier and more preferable.
Automatic Evaluation of Sketch Recognizers
(The Eurographics Association, 2009) Schmieder, Paul; Plimmer, Beryl; Blagojevic, Rachel; Cindy Grimm and Joseph J. LaViola, Jr.
We present our toolkit to automatically evaluate recognition algorithms. There are few published comparative evaluations of sketch recognition algorithms and those that exist do not provide benchmarking or direct comparisons because standardised data and an evaluation platform is not available. By unifying data collection, labelling and evaluation in one tool, fair, flexible and comprehensive evaluations are possible. Currently we have 6 existing recognizers integrated into this tool. With our initial evaluations of these recognizers we have observed that the context from which training data is taken has an effect on recognition success rates. These results suggest that an evaluation platform such as this is a powerful adjunct for sketch recognition research.
Automatic Interpretation of Depiction Conventions in Sketched Diagrams
(The Eurographics Association, 2008) Lockwood, Kate; Lovett, Andrew; Forbus, Ken; Dehghani, Morteza; Usher, Jeff; Christine Alvarado and Marie-Paule Cani
Diagrams are used in many educational settings to convey physical and spatial information. Sketching is used, in turn, to test students' understanding of course concepts. The availability of Tablet PCs offer an exciting opportunity to create intelligent tutoring systems which automatically provide students with feedback on sketched work, and to create systems which can capture knowledge via interaction with people. However, for such systems to provide useful and relevant feedback, the software must be able to interpret diagrams that students have drawn. Interpreting diagrams correctly requires an understanding of some basic depiction conventions common in diagrammatic representation. Here we describe how to combine general semantic information about objects in sketched diagrams with geometric information from the sketch to aid in the interpretation of regions and edges. This system is implemented as an extension to the CogSketch sketch understanding system.
Automatic Interpretation of Proofreading Sketches
(The Eurographics Association, 2006) Rodríguez, Jose A.; Sánchez, Gemma; Lladós, Josep; Thomas Stahovich and Mario Costa Sousa
We present a sketch-based system for proofreading documents. The gestures and words drawn by the proofreader on a document view are translated into high-level actions that represent editions such as replace, insert, delete and others. Our particular system is not restricted to a predefined alphabet of gestures. Instead, any symbol can be employed for striking out words or drawing inserts. This provides more flexibility and adaptability to the user. In contrast to other similar works, our interface integrates interpretation and recognition of handwritten words. The described system has been implemented for proofreading digital documents on screen but also for paper documents printed on Anoto paper and annotated using a digital pen.
Automatic Learning of Symbol Descriptions Avoiding Topological Ambiguities
(The Eurographics Association, 2006) Mas, Juan; Lamiroy, Bart; Sanchez, Gemma; Llados, Josep; Thomas Stahovich and Mario Costa Sousa
In this paper we address both automatic recognition of sketched symbols and the construction of the corresponding models from user drawn examples. Our approach is based on a two stage process. In a first phase we use an Adjacency Grammar to express topological properties of the symbol. In order to be able to further disambiguate topologically similar configurations on the rules of the grammar that are triggered by the recognition process produce a set of local geometric invariants is defined. The combination of both steps results in an efficient recognition method for user drawn sketches. Furthermore, we show that the same approach can easily be adapted for the generation of Adjacency Grammars from user provided and hand drawn examples.
Automatic Single-View Character Model Reconstruction
(ACM, 2013) Buchanan, Philip; Mukundany, R.; Doggett, Michael; Levent Burak Kara and Cindy Grimm
In this paper we present a new method for automatically constructing 3D meshes from a single input image. With the increasing content demands of modern digital entertainment and the expectation of involvement from users, automatic artist-free systems are an important step in allowing user generated content and rapid game prototyping. Our system proposes a novel heuristic for the creation of a 3D mesh from a single piece of non-occluding 2D concept art. By extracting a skeleton structure, approximating the 3D orientation and analysing line curvature properties, appropriate centrepoints can be found around which to create the cross-sectional slices used to build a final triangle mesh. Our results show that a single 2D input image can be used to generate a rigged 3D lowpolygon model suitable for use in realtime applications.
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.
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.

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