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29 results on '"Stefanie Hahmann"'

1. Feature Lines Modification Based on As-Stiff-As-Needed Surface Deformation

Author

Youna Le Vaou, Matthieu Mika, Jean-Claude Léon, Stéphane Masfrand, Stefanie Hahmann, Authoring and directing story worlds (ANIMA), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Calcul des Variations, Géométrie, Image (CVGI), Laboratoire Jean Kuntzmann (LJK), Université Grenoble Alpes (UGA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Groupe PSA - Centre Technique de Vélizy [Vélizy-Villacoublay]

Subjects
Surface (mathematics), physicalbased deformation, Computer science, Traction (engineering), Boundary (topology), Mechanical engineering, 02 engineering and technology, Deformation (meteorology), [INFO.INFO-CG]Computer Science [cs]/Computational Geometry [cs.CG], 01 natural sciences, Industrial and Manufacturing Engineering, Computer aided design CAD, 0202 electrical engineering, electronic engineering, information engineering, Polygon mesh, ComputingMethodologies_COMPUTERGRAPHICS, 020207 software engineering, aesthetic design, Compression (physics), Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], 0104 chemical sciences, Computer Science Applications, 010404 medicinal & biomolecular chemistry, Feature (computer vision), feature lines, Line (geometry), mesh deformation
Abstract

International audience; Aesthetic surface mesh modification, guided by a deforming feature line, is still a challenging task. Whereas most existing surface deformation methods work well when the new surface is stretched or isometrically deformed, in case of areas subjected to compression, unwanted bulging may appear. This configuration typically appears when a designer slides a feature line along the input surface. In this paper, we present a new approach for feature line modification solving the surface bulging problem. We consider physically-based deformation methods applied to surface meshes and characterize configurations that produce compression loading from a mechanical standpoint. Then, the deformation area is decomposed into two sub-domains with a boundary modification of the one subjected to compression loading. Thus, during a subsequent deformation, this sub-domain no longer undergoes a compression loading but rather a traction loading, which ultimately prevents bulging. This transformation looks like a retraction of this surface area and a corresponding processing pipeline is set up. Our feature line modification method is intuitive to use and runs interactively, making it attractive to be used during design reviews in immersive environments. Industrial examples and comparisons with state-of-theart physically-based deformation methods validate the proposed approach.

Published
2021

2. Fashion Transfer: Dressing 3D Characters from Stylized Fashion Sketches

Author

Marie-Paule Cani, Amélie Fondevilla, Stefanie Hahmann, Damien Rohmer, Adrien Bousseau, Structural Models and Tools in Computer Graphics (IRIT-STORM), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Laboratoire d'informatique de l'École polytechnique [Palaiseau] (LIX), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Authoring and directing story worlds (ANIMA), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), GRAPHics and DEsign with hEterogeneous COntent (GRAPHDECO), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), ANR-19-CE38-0009,Structures,Structures: hierarchical motion representation for stylized rendering(2019), European Project: 714221,H2020 Pilier ERC,ERC-2016-STG-714221,D3(2017), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, and Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)

Subjects
0209 industrial biotechnology, Fashion design, business.industry, Computer science, Character (computing), One-to-many, 020207 software engineering, 02 engineering and technology, Clothing, Computer Graphics and Computer-Aided Design, Sketch, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Style (sociolinguistics), Key (music), Silhouette, 020901 industrial engineering & automation, Human–computer interaction, 0202 electrical engineering, electronic engineering, information engineering, business, ComputingMethodologies_COMPUTERGRAPHICS
Abstract

International audience; Fashion design often starts with hand-drawn, expressive sketches that communicate the essence of a garment over idealized human bodies. We propose an approach to automatically dress virtual characters from such input, previously complemented with user-annotations. In contrast to prior work requiring users to draw garments with accurate proportions over each virtual character to be dressed, our method follows a style transfer strategy : the information extracted from a single, annotated fashion sketch can be used to inform the synthesis of one to many new garment(s) with similar style, yet different proportions. In particular, we define the style of a loose garment from its silhouette and folds, which we extract from the drawing. Key to our method is our strategy to extract both shape and repetitive patterns of folds from the 2D input. As our results show, each input sketch can be used to dress a variety of characters of different morphologies, from virtual humans to cartoon-style characters.

Published
2021
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3. First Person Sketch-based Terrain Editing

Author

Arnaud Emilien, Marie-Paule Cani, Adrien Bernhardt, Stefanie Hahmann, Flora Ponjou Tasse, Computer Laboratory [Cambridge], University of Cambridge [UK] (CAM), Intuitive Modeling and Animation for Interactive Graphics & Narrative Environments (IMAGINE), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Département d'Informatique et de Recherche Opérationnelle [Montreal] (DIRO), Université de Montréal (UdeM), European Project: 291184,EC:FP7:ERC,ERC-2011-ADG_20110209,EXPRESSIVE(2012), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), and Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)

Subjects
business.industry, Computer science, media_common.quotation_subject, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, Terrain, 02 engineering and technology, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], GeneralLiterature_MISCELLANEOUS, Sketch, First person, 020204 information systems, Computer graphics (images), Perception, 0202 electrical engineering, electronic engineering, information engineering, Computer vision, Artificial intelligence, business, ComputingMethodologies_COMPUTERGRAPHICS, media_common
Abstract

International audience; We present a new method for first person sketch-based editing of terrain models. As in usual artistic pictures, the input sketch depicts complex silhouettes with cusps and T-junctions, which typically correspond to non-planar curves in 3D. After analysing depth constraints in the sketch based on perceptual cues, our method best matches the sketched silhouettes with silhouettes or ridges of the input terrain. A specific deformation algorithm is then applied to the terrain, enabling it to exactly match the sketch from the given perspective view, while insuring that none of the user-defined silhouettes is hidden by another part of the terrain. As our results show, this method enables users to easily personalize an existing terrain, while preserving its plausibility and style.

Published
2020

4. Foreword to the Special Section on Shape Modeling International 2018

Author

Stefanie Hahmann, Evangelos Kalogerakis, and Abel J. P. Gomes

Subjects
Human-Computer Interaction, Engineering drawing, Computer science, 0202 electrical engineering, electronic engineering, information engineering, General Engineering, Special section, 020207 software engineering, 020201 artificial intelligence & image processing, 02 engineering and technology, Computer Graphics and Computer-Aided Design
Published
2018

5. As-Stiff-As-Needed Surface DeformationCombining ARAP Energy with an Anisotropic Material

Author

Jean-Claude Léon, Stéphane Masfrand, Matthieu Mika, Youna Le Vaou, Stefanie Hahmann, Intuitive Modeling and Animation for Interactive Graphics & Narrative Environments (IMAGINE), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Groupe PSA - Centre Technique de Vélizy [Vélizy-Villacoublay], and Authoring and directing story worlds (ANIMA)

Subjects
Surface (mathematics), 0209 industrial biotechnology, Computer science, Mechanical engineering, Rigidity (psychology), anisotropy, 02 engineering and technology, Deformation (meteorology), Edge (geometry), [INFO.INFO-CG]Computer Science [cs]/Computational Geometry [cs.CG], Orthotropic material, Industrial and Manufacturing Engineering, stiffness, 020901 industrial engineering & automation, 0202 electrical engineering, electronic engineering, information engineering, medicine, Point (geometry), Structural mechanics, Stiffness, 020207 software engineering, [INFO.INFO-IA]Computer Science [cs]/Computer Aided Engineering, Computer Graphics and Computer-Aided Design, design review, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Computer Science Applications, shape design, shape deformation, medicine.symptom, as-rigid-as-possible
Abstract

International audience; The creation of man-made shapes can be seen as the exploration of designers’ ‘Mental Shape Space’, often supported by design reviews. To improve communication among the designers during these reviews, we introduce a new physically-based method to intuitively deform man-made shapes. This method is based on as-rigid-as possible (ARAP) shape deformation methods, known to offer a direct surface manipulation and to generate visually pleasant shapes by minimizing local deviations from rigidity. However, the organic character of ARAP shape deformations leads to undesired effects, such as surface collapsing or bulging because of an inappropriate stiffness model over the object. In this paper, we first link the designers’ needs to ARAP handle-based variational mesh deformation processes. Then, we study and characterize the ARAP energy and its variants from a structural mechanics point of view. Our insight is that controlling the material stiffness could prevent the undesirable organic effects. Yet, we shed light on the fact that none of the ARAP-based methods offers an appropriate stiffness distribution over the object from a mechanical standpoint. We do so by introducing an appropriate anisotropic material, called orthotropic material, to improve the stiffness distribution over the surface and its deformation behavior for man-made shapes. This material is associated with a membrane-like structural behavior to further improve the stiffness distribution. Thanks to these settings, we derive a robust and intuitive deformation process that produces an anisotropic mesh deformation based on new edge weights in the ARAP formulation. The benefits of our new method are finally illustrated by typical design examples from the automotive industry and other man-made shapes.

Published
2020

6. A Salience Measure for 3D Shape Decomposition and Sub-parts Classification

Author

Axel Carlier, Géraldine Morin, Kathryn Leonard, Stefanie Hahmann, Thibault Blanc-Beyne, Real Expression Artificial Life (IRIT-REVA), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Ecole Nationale Supérieure d'Electrotechnique, d'Electronique, d'Informatique, d'Hydraulique et de Télécommunications (ENSEEIHT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT), Occidental College, Intuitive Modeling and Animation for Interactive Graphics & Narrative Environments (IMAGINE ), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Laboratoire Jean Kuntzmann (LJK ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - INPT (FRANCE), Institut polytechnique de Grenoble (FRANCE), Institut National de la Recherche en Informatique et en Automatique - INRIA (FRANCE), Université Grenoble Alpes - UGA (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université Toulouse - Jean Jaurès - UT2J (FRANCE), Université Toulouse 1 Capitole - UT1 (FRANCE), Occidental College - OXY (USA), Laboratoire Jean Kuntzmann - LJK (Grenoble, France), and Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)

Subjects
Computer science, Computation, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, shape analysis, 02 engineering and technology, [INFO.INFO-CG]Computer Science [cs]/Computational Geometry [cs.CG], medial axis, Piecewise linear function, Medial axis, Salience (neuroscience), 0202 electrical engineering, electronic engineering, information engineering, Salience measure, Synthèse d'image et réalité virtuelle, ComputingMethodologies_COMPUTERGRAPHICS, WEDF, business.industry, 020207 software engineering, Pattern recognition, Perceptual salience, part hierarchy, Computer Graphics and Computer-Aided Design, Hierarchical decomposition, Shape analysis, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Part hierarchy, Modeling and Simulation, 020201 artificial intelligence & image processing, Geometry and Topology, Artificial intelligence, 3D shape decomposition, business, Software, salience measure, Shape analysis (digital geometry)
Abstract

International audience; This paper introduces a measure of significance on a curve skeleton of a 3D piecewise linear shape mesh, allowing the computation of both the shape's parts and their saliency. We begin by reformulating three existing pruning measures into a non-linear PCA along the skeleton. From this PCA, we then derive a volume-based salience measure, the 3D WEDF, that determines the relative importance to the global shape of the shape part associated to a point of the skeleton. First, we provide robust algorithms for computing the 3D WEDF on a curve skeleton, independent on the number of skeleton branches. Then, we cluster the WEDF values to partition the curve skeleton, and coherently map the decomposition to the associated surface mesh. Thus, we develop an unsupervised hierarchical decomposition of the mesh faces into visually meaningful shape regions that are ordered according to their degree of perceptual salience. The shape analysis tools introduced in this paper are important for many applications including shape comparison, editing, and compression.

Published
2018

7. Sketching Folds

Author

Amaury Jung, Marie-Paule Cani, Antoine Begault, Laurence Boissieux, Damien Rohmer, Stefanie Hahmann, Intuitive Modeling and Animation for Interactive Graphics & Narrative Environments (IMAGINE), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), École supérieure de Chimie Physique Electronique de Lyon (CPE), SED [Grenoble], Inria Grenoble - Rhône-Alpes, European Project: 291184,EC:FP7:ERC,ERC-2011-ADG_20110209,EXPRESSIVE(2012), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), École Supérieure de Chimie Physique Électronique de Lyon (CPE), and Service Expérimentation et Développement (SED [Grenoble])

Subjects
Computer science, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 02 engineering and technology, [INFO.INFO-CG]Computer Science [cs]/Computational Geometry [cs.CG], Shape Modeling, Silhouette, Planar, Sketch-based modeling, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, developable surfaces, Computer vision, folds generation, ComputingMethodologies_COMPUTERGRAPHICS, Developable surface, business.industry, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.5: Computational Geometry and Object Modeling, 020207 software engineering, Computer Graphics and Computer-Aided Design, Sketch, non-planar silhouettes, 020201 artificial intelligence & image processing, Artificial intelligence, sketch-based modeling, business, [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA]
Abstract

International audience; We present the first sketch-based modeling method for developable surfaces with pre-designed folds, such as garments or leather products. The main challenge we address for building folded surfaces from sketches is that silhouette strokes on the sketch correspond to discontinuous sets of non-planar curves on the 3D model. We introduce a new zippering algorithm for progressively identifying silhouette edges on the model and tying them to silhouette strokes. Our solution ensures that the strokes are fully covered and optimally sampled by the model. This new method, interleaved with developability optimization steps, is implemented in a multi-view sketching system where the user can sketch the contours of internal folds in addition to the usual silhouettes, borders and seam lines. All strokes are interpreted as hard constraints, while developability is only optimized. The developability error map we provide then enables users to add local seams or darts where needed and progressively improve their design. This makes our method robust even to coarse input, for which no fully developable solution exists.

Published
2015

8. Patterns from Photograph: Reverse-Engineering Developable Products

Author

Damien Rohmer, Stefanie Hahmann, Amélie Fondevilla, Adrien Bousseau, Marie-Paule Cani, Intuitive Modeling and Animation for Interactive Graphics & Narrative Environments (IMAGINE ), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Laboratoire Jean Kuntzmann (LJK ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), GRAPHics and DEsign with hEterogeneous COntent (GRAPHDECO), Inria Sophia Antipolis - Méditerranée (CRISAM), Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), École supérieure de Chimie Physique Electronique de Lyon (CPE), European Project: 291184,EC:FP7:ERC,ERC-2011-ADG_20110209,EXPRESSIVE(2012), and École Supérieure de Chimie Physique Électronique de Lyon (CPE)

Subjects
Reverse engineering, Surface (mathematics), Property (philosophy), Computer science, 02 engineering and technology, computer.software_genre, 01 natural sciences, Projection (mathematics), Sketch-based modeling, image-based modeling, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, Computer vision, developable surfaces, Developable surface, business.industry, General Engineering, 020207 software engineering, Object (computer science), Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], 0104 chemical sciences, Human-Computer Interaction, 010404 medicinal & biomolecular chemistry, Artificial intelligence, sketch-based modeling, business, computer, Normal, single-view 3D reconstruction
Abstract

International audience; Developable materials are ubiquitous in design and manufacturing. Unfortunately, general-purpose modeling tools are not suited to modeling 3D objects composed of developable parts. We propose an interactive tool to model such objects from a photograph. Users of our system load a single picture of the object they wish to model, which they annotate to indicate silhouettes and part boundaries. Assuming that the object is symmetric, we also ask users to provide a few annotations of symmetric correspondences. The object is then automatically reconstructed in 3D. At the core of our method is an algorithm to infer the 2D projection of rulings of a developable surface from the traced silhouettes and boundaries. We impose that the surface normal is constant along each ruling, which is a necessary property for the surface to be developable. We complement these developability constraints with symmetry constraints to lift the curve network in 3D. In addition to a 3D model, we output 2D patterns enabling to fabricate real prototypes of the object on the photo. This makes our method well suited for reverse engineering products made of leather, bent cardboard or metal sheets.

Published
2017

9. Interactive paper tearing

Author

Camille Schreck, Damien Rohmer, Stefanie Hahmann, Intuitive Modeling and Animation for Interactive Graphics & Narrative Environments (IMAGINE ), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Laboratoire Jean Kuntzmann (LJK ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Department of Computer Science [Lyon] (CPE), École supérieure de Chimie Physique Electronique de Lyon (CPE)-Université de Lyon, European Project: 291184,EC:FP7:ERC,ERC-2011-ADG_20110209,EXPRESSIVE(2012), and École Supérieure de Chimie Physique Électronique de Lyon (CPE)-Université de Lyon

Subjects
Three-Dimensional Graphics and Realism, Computer science, Scientific visualization, 020207 software engineering, Context (language use), ComputerApplications_COMPUTERSINOTHERSYSTEMS, 02 engineering and technology, Animation, 01 natural sciences, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Computer graphics, Real-time computer graphics, Physics::Plasma Physics, Computer graphics (images), 0103 physical sciences, Path (graph theory), Tearing, Physics::Space Physics, 0202 electrical engineering, electronic engineering, information engineering, Tears, 010306 general physics, Algorithm, 3D computer graphics
Abstract

International audience; We propose an efficient method to model paper tearing in the context of interactive modeling. The method uses geometrical information to automatically detect potential starting points of tears. We further introduce a new hybrid geometrical and physical-based method to compute the trajectory of tears while procedurally synthesizing high resolution details of the tearing path using a texture based approach. The results obtained are compared with real paper and with previous studies on the expected geometric paths of paper that tears.

Published
2017

10. The 2D shape structure dataset: A user annotated open access database

Author

Axel Carlier, Misha Collins, Stefanie Hahmann, Géraldine Morin, Kathryn Leonard, Centre National de la Recherche Scientifique - CNRS (FRANCE), California State University Channel Islands - CSU-CI (USA), GISHWHES (USA), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Institut polytechnique de Grenoble (FRANCE), Institut National de la Recherche en Informatique et en Automatique - INRIA (FRANCE), Université Grenoble Alpes - UGA (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université Toulouse - Jean Jaurès - UT2J (FRANCE), Université Toulouse 1 Capitole - UT1 (FRANCE), Laboratoire Jean Kuntzmann (Grenoble, France), Real Expression Artificial Life (IRIT-REVA), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Institut National Polytechnique (Toulouse) (Toulouse INP), California State University Channel Islands, Intuitive Modeling and Animation for Interactive Graphics & Narrative Environments (IMAGINE ), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Laboratoire Jean Kuntzmann (LJK ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), GISHWHES, Inc., European Project: 291184,EC:FP7:ERC,ERC-2011-ADG_20110209,EXPRESSIVE(2012), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, and Institut National Polytechnique de Toulouse - INPT (FRANCE)

Subjects
Majority rule, 2d shape hierarchy, Computer science, shape decomposition, 02 engineering and technology, Crowdsourcing, 050105 experimental psychology, medial axis, Traitement des images, 2d shape structure, 0202 electrical engineering, electronic engineering, information engineering, Decomposition (computer science), Traitement du signal et de l'image, Datasets, 0501 psychology and cognitive sciences, Computer vision, Synthèse d'image et réalité virtuelle, 2d shape decomposition, ComputingMethodologies_COMPUTERGRAPHICS, Structure (mathematical logic), Ground truth, Information retrieval, Hierarchy (mathematics), business.industry, datasets, 05 social sciences, General Engineering, 2D shape, [INFO.INFO-CV]Computer Science [cs]/Computer Vision and Pattern Recognition [cs.CV], 020207 software engineering, Vision par ordinateur et reconnaissance de formes, Intelligence artificielle, Computer Graphics and Computer-Aided Design, Outcome (probability), [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Human-Computer Interaction, user study, Index (publishing), shape structure, crowdsourcing, Medial axis, Artificial intelligence, business, shape hierarchy
Abstract

In this paper we present the 2D Shape Structure database, a public, user-generated dataset of 2D shape decompositions into a hierarchy of shape parts with geometric relationships retained. It is the outcome of a large-scale user study obtained by crowdsourcing, involving over 1200 shapes in 70 shape classes, and 2861 participants. A total of 41,953 annotations has been collected with at least 24 annotations per shape. For each shape, user decompositions into main shape, one or more levels of parts, and a level of details are available. This database reinforces a philosophy that understanding shape structure as a whole, rather than in the separated categories of parts decomposition, parts hierarchy, and analysis of relationships between parts, is crucial for full shape understanding. We provide initial statistical explorations of the data to determine representative ("mean") shape annotations and to determine the number of modes in the annotations. The primary goal of the paper is to make this rich and complex database openly available (through the website http://2dshapesstructure.github.io/index.html), providing the shape community with a ground truth of human perception of holistic shape structure. Graphical abstractDisplay Omitted HighlightsOver 1200 shapes were annotated by 2861 users resulting in 41,953 annotated shapes.Each shape is decomposed into a main shape, levels of parts and a level of details.A majority vote shape, and a recommended number of modes for each shape are provided.The data is available at http://2dshapesstructure.github.io/index.html.

Published
2016

11. Real-Time Continuous Self-Replicating Details for Shape Deformation

Author

Damien Rohmer, Stefanie Hahmann, Marie-Paule Cani, École supérieure de Chimie Physique Electronique de Lyon (CPE), Intuitive Modeling and Animation for Interactive Graphics & Narrative Environments (IMAGINE), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), European Project: 291184,EC:FP7:ERC,ERC-2011-ADG_20110209,EXPRESSIVE(2012), École Supérieure de Chimie Physique Électronique de Lyon (CPE), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), and Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)

Subjects
Computer science, Bent molecular geometry, Deformation (meteorology), Time coherency, Self-similar Details, [INFO.INFO-CG]Computer Science [cs]/Computational Geometry [cs.CG], Shape Modeling, Effective solution, Set (abstract data type), Simple (abstract algebra), Computer vision, [INFO]Computer Science [cs], Details, ComputingMethodologies_COMPUTERGRAPHICS, business.industry, General Engineering, Replication of Details, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS/I.3.5: Computational Geometry and Object Modeling, Computer Graphics and Computer-Aided Design, Deformation, Human-Computer Interaction, Distribution (mathematics), Artificial intelligence, business, Coherence (physics), Gesture
Abstract

We address continuous free-form sculpting of 3D models that carry self-similar geometric details. In addition to being maintained when the model is bent or twisted, repetitive details should be duplicated rather than deformed in stretched regions, so that their distribution and appearance are preserved. Doing so in a temporally coherent way is essential in applications where the user sculpts through continuous deformation gestures. We propose a simple, yet effective solution for achieving such temporal coherence while enabling duplication of details. Our method maintains the set of existing details during stretch but seamlessly grows new ones in between. Similarly, some of the details progressively fade out when a region shrinks. Our solution is example-based: it uses the triangles of the initial support surface as exemplars to be selected and re-used in deformed regions. As our results show, our method achieves continuous free-form deformation of complex models while best preserving, at each time step, the properties and appearance of their initial distribution of details. Graphical abstractDisplay Omitted HighlightsWe propose a method for continuous self-replicating details for shape deformation.This method ensures temporal coherence during mesh deformation.It preserves the distribution of self-similar geometric details at any time step.The method is applicable in real-time and thus proving visually smooth feedback.

Published
2015

12. Replaceable Substructures for Efficient Part-Based Modeling

Author

Damien Rohmer, Michael Wand, Ulysse Vimont, Stefanie Hahmann, Han Liu, Marie-Paule Cani, Niloy J. Mitra, King Abdullah University of Science and Technology (KAUST), Intuitive Modeling and Animation for Interactive Graphics & Narrative Environments (IMAGINE), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Utrecht University [Utrecht], École supérieure de Chimie Physique Electronique de Lyon (CPE), Department Computer Science [London] (UCL-CS), University College of London [London] (UCL), European Project: 291184,EC:FP7:ERC,ERC-2011-ADG_20110209,EXPRESSIVE(2012), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), and École Supérieure de Chimie Physique Électronique de Lyon (CPE)

Subjects
Matching (graph theory), Computer science, Boundary (topology), 020207 software engineering, 02 engineering and technology, Topology, Computer Graphics and Computer-Aided Design, Graph, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Range (mathematics), Consistency (database systems), 0202 electrical engineering, electronic engineering, information engineering, Local consistency, Graph (abstract data type), 020201 artificial intelligence & image processing, Algorithm, Time complexity, Mixing (physics)
Abstract

International audience; A popular mode of shape synthesis involves mixing and matching parts from different objects to form a coherent whole. The key challenge is to efficiently synthesize shape variations that are plausible, both locally and globally. A major obstacle is to assemble the objects with local consistency, i.e., all the connections between parts are valid with no dangling open connections. The combinatorial complexity of this problem limits existing methods in geometric and/or topological variations of the synthesized models. In this work, we introduce replaceable substructures as arrangements of parts that can be interchanged while ensuring boundary consistency. The consistency information is extracted from part labels and connections in the original source models. We present a polynomial time algorithm that discovers such substructures by working on a dual of the original shape graph that encodes inter-part connectivity. We demonstrate the algorithm on a range of test examples producing plausible shape variations, both from a geometric and from a topological viewpoint.

Published
2015

13. Feature-based terrain editing from complex sketches

Author

Marie-Paule Cani, Arnaud Emilien, Neil A. Dodgson, Stefanie Hahmann, Flora Ponjou Tasse, Dodgson, Neil [0000-0001-7649-8528], Apollo - University of Cambridge Repository, Computer Laboratory [Cambridge], University of Cambridge [UK] (CAM), Intuitive Modeling and Animation for Interactive Graphics & Narrative Environments (IMAGINE), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Département d'Informatique et de Recherche Opérationnelle [Montreal] (DIRO), Université de Montréal (UdeM), European Project: 291184,EC:FP7:ERC,ERC-2011-ADG_20110209,EXPRESSIVE(2012), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes, and Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)

Subjects
Matching (graph theory), Computer science, 3d terrain, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Silhouettes, Terrain, GeneralLiterature_MISCELLANEOUS, Sketch-based modeling, Computer graphics (images), Sketch-based modelling, Feature based, Computer vision, ComputingMethodologies_COMPUTERGRAPHICS, First person editing, business.industry, General Engineering, Terrain rendering, Computer Graphics and Computer-Aided Design, Sketch, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Human-Computer Interaction, First person, Artificial intelligence, business
Abstract

We present a new method for first person sketch-based editing of terrain models. As in usual artistic pictures, the input sketch depicts complex silhouettes with cusps and T-junctions, which typically correspond to non-planar curves in 3D. After analysing depth constraints in the sketch based on perceptual cues, our method best matches the sketched silhouettes with silhouettes or ridges of the input terrain. A deformation algorithm is then applied to the terrain, enabling it to exactly match the sketch from the given perspective view, while insuring that none of the user-defined silhouettes is hidden by another part of the terrain. We extend this sketch-based terrain editing framework to handle a collection of multi-view sketches. As our results show, this method enables users to easily personalize an existing terrain, while preserving its plausibility and style. Graphical abstractWe present a new method for first person sketch-based editing of terrain models. As our results show, our method enables users to easily personalize an existing terrain, while preserving its plausibility and style.Display Omitted HighlightsAn algorithm for ordering strokes in a 2D complex sketch.A method for matching 3D terrain features with 2D user-specified silhouettes.A method for editing terrain with a collection of multi-view sketches.

Published
2014

14. An Analysis of the Transformation Requirements for Digital Mock-Ups of Structural Assembly Simulations

Author

Flavien Boussuge, Jean-Claude Léon, Lionel Fine, and Stefanie Hahmann

Subjects
0209 industrial biotechnology, Computer science, Process (engineering), Simulation modeling, 020207 software engineering, Shape transformation, 02 engineering and technology, Industrial engineering, Set (abstract data type), 020901 industrial engineering & automation, Transformation (function), Component (UML), 0202 electrical engineering, electronic engineering, information engineering, Idealization, Key (cryptography)
Abstract

In order to set up a framework dedicated to the transformation of Digital Mock-Ups (DMUs) into simulation models, this paper exposes the problematic of simulation assembly model preparation. It analyses the differences between standalone component and assembly preparations to justify the reasons of time consuming tasks specific to assemblies. To this end, the content of a DMU is analyzed to explain why information about interfaces between components is missing in DMUs and how to derive the shape idealization of industrial assembly models, resulting in categories of DMU transformations. There, repetitive configurations emerge as a key issue to process large assembly models and the use of functional data appears to be critical to automate assembly transformations. Then, starting from the concepts of simulation objectives, user-specified hypotheses, connections between them and shape transformation categories are analyzed to extract dependencies. As a result of these dependencies, a model preparation methodology is derived that address the shape transformation categories specific to assemblies. This methodology is already a means to improve the efficiency of an assembly simulation preparation process.

Published
2012

15. Volume Preserving FFD for Programmable Graphics Hardware

Author

Sébastien Barbier, Georges-Pierre Bonneau, Stefanie Hahmann, Hans Hagen, Gershon Elber, Intuitive Modeling and Animation for Interactive Graphics & Narrative Environments (IMAGINE), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Models and Algorithms for Visualization and Rendering (MAVERICK), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Center for Graphics and Geometric Computing (CGGC), Technion - Israel Institute of Technology [Haifa], Department of Computer Science [Kaiserslautern], Technische Universität Kaiserslautern (TU Kaiserslautern), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Inria Grenoble - Rhône-Alpes, and Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)

Subjects
Computer science, Graphics hardware, OpenGL, Constraint (computer-aided design), Direct manipulation, 020207 software engineering, Free form deformations (FFD), 02 engineering and technology, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Nonlinear programming, Computer graphics, CUDA, Volume preservation, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Computer Vision and Pattern Recognition, Geometric modeling, Algorithm, Software, Computer animation, ComputingMethodologies_COMPUTERGRAPHICS
Abstract

International audience; Free Form Deformation (FFD) is a well established technique for deforming arbitrary object shapes in space. Although more recent deformation techniques have been introduced, amongst them skeleton-based deformation and cage based deformation, the simple and versatile nature of FFD is a strong advantage, and justifies its presence in nowadays leading commercial geometric modeling and animation software systems. Since its introduction in the late 80's, many improvements have been proposed to the FFD paradigm, including control lattices of arbitrary topology, direct shape manipulation and GPU implementation. Several authors have addressed the problem of volume preserving FFD. These previous approaches either make use of expensive non-linear optimization techniques, or resort to first order approximation suitable only for small-scale deformations. In this paper we take advantage from the multi-linear nature of the volume constraint in order to derive a simple, exact and explicit solution to the problem of volume preserving FFD. Two variants of the algorithm are given, without and with direct shape manipulation. Moreover, the linearity of our solution enables to implement it efficiently on GPU.

Published
2012

16. Active Geometry for Game Characters

Author

Marie-Paule Cani, Damien Rohmer, Stefanie Hahmann, Virtual environments for animation and image synthesis of natural objects (EVASION), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Modélisation Géométrique & Multirésolution pour l'Image (MGMI), Laboratoire Jean Kuntzmann (LJK), Ronan Boulic, Yiorgos Chrysanthou, and and Taku Komura

Subjects
Procedural model, Current (mathematics), Computer science, Computation, Volume (computing), Geometry, 020207 software engineering, 02 engineering and technology, Animation, GeneralLiterature_MISCELLANEOUS, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Skinning, Character (mathematics), Wrinkles, Computer graphics (images), Constant volume, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Layer (object-oriented design), Constant (mathematics), ComputingMethodologies_COMPUTERGRAPHICS
Abstract

International audience; Animating the geometry of a real-time character is typically done using fast methods such as smooth skinning or coarse physically- based animation. These methods are not able to capture realistic be- haviors such as flesh and muscles bulging with constant volume or fine wrinkling of animated garments. This paper advocates the use of ac- tive geometric models, applied on top of the current geometric layer, to mimic these behaviors without requiring any expensive computation. Our models fit into the standard animation pipe-line and can be tuned in an intuitive way thanks to their geometric nature.

Published
2010

17. Exact volume preserving skinning with shape control

Author

Damien Rohmer, Marie-Paule Cani, Stefanie Hahmann, Virtual environments for animation and image synthesis of natural objects (EVASION), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Modélisation Géométrique & Multirésolution pour l'Image (MGMI), and Laboratoire Jean Kuntzmann (LJK)

Subjects
Computer science, Locality, Constraint (computer-aided design), Skinning, 020207 software engineering, 02 engineering and technology, Animation, USable, Object (computer science), [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Constant Volume, Compression (functional analysis), Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Algorithm, Volume (compression), ComputingMethodologies_COMPUTERGRAPHICS
Abstract

International audience; In the real world, most objects do not loose volume when they deform: they may for instance compensate a local compression by inflating in the orthogonal direction, or, in the case of a character, preserve volume through specific bulges and folds. This paper presents a novel extension to smooth skinning, which not only offers an exact control of the object volume, but also enables the user to specify the shape of volume-preserving deformations through intuitive 1D profile curves. The method, a geometric post-processing to standard smooth skinning, perfectly fits into the usual production pipeline. It can be used whatever the desired locality of volume correction and does not bring any constraint on the original mesh. Several behaviors mimicking the way rubber-like materials and organic shapes respectively deform can be modeled. An improved algorithm for robustly computing skinning weights is also provided, making the method directly usable on complex characters, even for non-experts.

Published
2009

18. Local volume preservation for skinned characters

Author

Stefanie Hahmann, Damien Rohmer, Marie-Paule Cani, Virtual environments for animation and image synthesis of natural objects (EVASION), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Modélisation Géométrique & Multirésolution pour l'Image (MGMI), and Laboratoire Jean Kuntzmann (LJK)

Subjects
character animation, Computer science, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 02 engineering and technology, Set (abstract data type), Skinning, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, Computer vision, ComputingMethodologies_COMPUTERGRAPHICS, SSD, Rest (physics), volume preservation, business.industry, deformation, 020207 software engineering, Animation, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Character (mathematics), Character animation, 020201 artificial intelligence & image processing, I.3.7 [Computer Graphics]: Three-Dimensional, Artificial intelligence, skinning, Constant (mathematics), business, Volume (compression)
Abstract

Special Isuue: Proceedings of Pacific Graphics 2008, Tokyo Japan; International audience; Generating plausible deformations of a character skin within the standard production pipeline is a challenge. This paper presents a volume preservation method dedicated to skinned characters. As usual, the character is defined by a skin mesh at some rest pose and an animation skeleton. At each animation step, skin deformations are first computed using standard SSD. Our method then corrects the result using a set of local deformations which model the fold-over-free, constant volume behavior of soft tissues. This is done geometrically, without the need of any physically-based simulation. To make the method easily applicable, we also provide automatic ways to extract the local regions where volume is to be preserved and to compute adequate skinning weights, both based on the character's morphology.

Published
2008

19. Volume preservation of multiresolution meshes

Author

Georges-Pierre Bonneau, Stefanie Hahmann, Basile Sauvage, Laboratoire des Sciences de l'Image, de l'Informatique et de la Télédétection (LSIIT), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Modélisation Géométrique & Multirésolution pour l'Image (MGMI), Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Virtual environments for animation and image synthesis of natural objects (EVASION), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut National Polytechnique de Grenoble (INPG), NoE AIM@SHAPE, and Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)

Subjects
Theoretical computer science, Computer science, 02 engineering and technology, Volume mesh, [INFO.INFO-CG]Computer Science [cs]/Computational Geometry [cs.CG], 01 natural sciences, wavelets, 0202 electrical engineering, electronic engineering, information engineering, Polygon mesh, 0101 mathematics, ComputingMethodologies_COMPUTERGRAPHICS, multiresolution meshes, lifting scheme, deformation, 020207 software engineering, Animation, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Loop subdivision, 010101 applied mathematics, Geometric Modeling, I.3.5 [Computer Graphics]: Curve, surface, solid, Geometric modeling, volume constraint, Algorithm, Volume (compression)
Abstract

Proceedings of Eurographics'2007; International audience; Geometric constraints have proved to be efficient for improving the realism of shape animation. The present paper addresses the computation and the preservation of the volume enclosed by multiresolution meshes. A wavelet based representation allows the mesh to be handled at any level of resolution. The key contribution is the calculation of the volume as a trilinear form with respect to the multiresolution coefficients. Efficiency is reached thanks to the pre-processing of a sparse 3D data structure involving the transposition of the filters while represented as a lifting scheme. A versatile and interactive method for preserving the volume during a deformation process is then proposed. It is based on a quadratic minimization subject to a linearization of the volume constraint.

Published
2007

20. Constraint Modeling for Curves and Surfaces in CAGD: A Survey

Author

Robert Maculet, Jean-Claude Léon, Marc Daniel, Basile Sauvage, Stefanie Hahmann, Raphaël La Greca, David Ménegaux, Vincent Cheutet, Laboratoire des Sciences de l'Information et des Systèmes (LSIS), Centre National de la Recherche Scientifique (CNRS)-Arts et Métiers Paristech ENSAM Aix-en-Provence-Université de Toulon (UTLN)-Aix Marseille Université (AMU), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria), Istituto di Matematica Applicata e Tecnologie Informatiche ( IMATI ), Consiglio Nazionale delle Ricerche [Roma] ( CNR ), Laboratoire sols, solides, structures - risques [Grenoble] ( 3S-R ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut National Polytechnique de Grenoble ( INPG ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ), Laboratoire des Sciences de l'Information et des Systèmes ( LSIS ), Aix Marseille Université ( AMU ) -Université de Toulon ( UTLN ) -Arts et Métiers Paristech ENSAM Aix-en-Provence-Centre National de la Recherche Scientifique ( CNRS ), Modélisation Géométrique & Multirésolution pour l'Image ( MGMI ), Laboratoire Jean Kuntzmann ( LJK ), Université Pierre Mendès France - Grenoble 2 ( UPMF ) -Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ) -Université Pierre Mendès France - Grenoble 2 ( UPMF ) -Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ), Laboratoire Electronique, Informatique et Image ( Le2i ), Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire des Sciences de l'Image, de l'Informatique et de la Télédétection ( LSIIT ), Centre National de la Recherche Scientifique ( CNRS ), AS Contraintes en Modélisation Géométrique, Istituto di Matematica Applicata e Tecnologie Informatiche (IMATI), Consiglio Nazionale delle Ricerche [Roma] (CNR), Laboratoire sols, solides, structures - risques [Grenoble] (3SR), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS), Modélisation Géométrique & Multirésolution pour l'Image (MGMI), Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Laboratoire Electronique, Informatique et Image [UMR6306] (Le2i), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Arts et Métiers (ENSAM), Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM)-Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Laboratoire des Sciences de l'Image, de l'Informatique et de la Télédétection (LSIIT), Centre National de la Recherche Scientifique (CNRS), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Arts et Métiers Paristech ENSAM Aix-en-Provence-Centre National de la Recherche Scientifique (CNRS), Université de Bourgogne (UB)-École Nationale Supérieure d'Arts et Métiers (ENSAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Arts et Métiers Sciences et Technologies, and HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique (CNRS)

Subjects
curves, Engineering drawing, Computer science, Constraint (computer-aided design), [INFO.INFO-OH]Computer Science [cs]/Other [cs.OH], Constraint classification, Context (language use), 010103 numerical & computational mathematics, 02 engineering and technology, surfaces, [INFO.INFO-CG]Computer Science [cs]/Computational Geometry [cs.CG], 01 natural sciences, CAD/CAM, Constraint modeling, Software, Design objective, Industrial design, 0202 electrical engineering, electronic engineering, information engineering, industrial design, 0101 mathematics, business.industry, Applied Mathematics, 020207 software engineering, I.3.5 Computational Geometry and Object Modeling, [ INFO.INFO-GR ] Computer Science [cs]/Graphics [cs.GR], [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Computer Science Applications, Geometric design, Geometric Modeling, Modeling and Simulation, CAGD, [ INFO.INFO-CG ] Computer Science [cs]/Computational Geometry [cs.CG], [ INFO.INFO-OH ] Computer Science [cs]/Other [cs.OH], Geometry and Topology, Computer Vision and Pattern Recognition, Free-form curves and surfaces, Engineering design process, business, Geometric modeling, constraints
Abstract

International audience; Computer-Aided Geometric Design modelers are now based on powerful mathematical curve and surface models, but there is still a considerable need for efficient tools to handle, analyze and modify these objects. Designing product shapes using geometric operations on free-form curves and surfaces is still a tedious task. Moreover, designers would prefer to use meaningful tools to concentrate on design objectives expressed in terms of functionalities and constraints related to engineering topics and technical matters. This explains why constraint modeling in CAGD is an important challenge for the forthcoming years and the paper aims at setting up some of its foundations. The corresponding global modeling approaches already proposed in CAD are first exposed. The specific existing techniques for handling constraints on curves and surfaces are then surveyed. A synthesis of these techniques and our current studies allows us to suggest a classification of the different constraints which ought to be taken into account in a constraint based modeling CAGD software. Open issues in the context of engineering design are finally emphasized.

Published
2007

21. Constrained Multiresolution Geometric Modelling

Author

Gershon Elber, Stefanie Hahmann, Laboratoire de Modélisation et Calcul (LMC - IMAG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS), Center for Graphics and Geometric Computing (CGGC), Technion - Israel Institute of Technology [Haifa], Neil A. Dodgson, Michael S. Floater, and Malcolm A. Sabin

Subjects
Surface (mathematics), Theoretical computer science, Computer science, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Solid modelling, I.3.5 Computational Geometry and Object Modeling, 020207 software engineering, 02 engineering and technology, Solid modeling, Geometric modeling kernel, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Computational science, Geometric design, Control point, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Subdivision surface, ComputingMethodologies_COMPUTERGRAPHICS
Abstract

International audience; This paper surveys the state-of-the-art of geometric modeling techniques that integrate constraints, including direct shape manipulation, physics-based modeling, solid modeling and freeform deformations as well as implicit surface modeling. In particular, it focuses on recent advances of multiresolution modeling of shapes under constraints.

Published
2005

22. Editorial: Special issue on geometric modeling (Dagstuhl 2008)

Author

Gerald Farin, Stefanie Hahmann, Jörg Peters, and Wenping Wang

Subjects
Computational Mathematics, Numerical Analysis, Engineering drawing, Computational Theory and Mathematics, Computer science, Representation (systemics), Geometric modeling, Computer communication networks, Software, Field (computer science), Computer Science Applications, Theoretical Computer Science
Abstract

The 7th Dagstuhl seminar on Geometric Modeling was held in May 2008 at the Leibniz-Zentrum fur Informatik at Schloss Dagstuhl in Germany. The participants came from 4 continents and 19 countries. There were a total of 46 technical presentations. The seminar was also the setting for the John Gregory Award. The award, named after a pioneer of the field, honored the long-term innovative contributions to field of Hartmut Prautzsch, Helmut Pottmann and Tom Sederberg. The seminar succeeded in bringing together leading researchers to present and discuss radically different approaches to the challenge of modeling complex geometric phenomena on the computer. Acquisition, representation and analysis of 3-dimensional geometry call for the combination of technically complex and often

Published
2009

23. Special issue on constrained design of curves and surfaces

Author

Panagiotis Kaklis, Paolo Costantini, Tom Lyche, and Stefanie Hahmann

Subjects
Computer science, Computer Graphics and Computer-Aided Design, Industrial and Manufacturing Engineering, Computer Science Applications
Published
2008

25. Curve and Surface Interrogation

Author

Burkard Wördenweber, Hans Hagen, Yasuo Nakajima, Thomas Schreiber, Ernst Gschwind, and Stefanie Hahmann

Subjects
Surface (mathematics), Computer science, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Process (computing), Mechanical engineering, CAD, symbols.namesake, Geometric design, Quality (physics), Gaussian curvature, symbols, Focal surface, Interrogation, ComputingMethodologies_COMPUTERGRAPHICS
Abstract

Free-form curves and surfaces are very important for sophisticated CAD/CAM Systems. Apart from the geometric modelling aspect of these curves and surfaces, the analysis of their quality is a necessary tool in the design and construction process. The purpose of this paper is to give a critical survey on curve and surface interrogation methods and to present generalized focal surfaces as a new surface interrogation tool.

Published
1993

26. Variational Surface Design and Surface Interrogation

Author

Stefanie Hahmann, Georges-Pierre Bonneau, Hans Hagen, and Technische Universität Kaiserslautern (TU Kaiserslautern)

Subjects
Surface (mathematics), 0209 industrial biotechnology, Operations research, Computer science, media_common.quotation_subject, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Mechanical engineering, 020207 software engineering, 02 engineering and technology, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], 020901 industrial engineering & automation, Data point, Geometric design, 0202 electrical engineering, electronic engineering, information engineering, Quality (business), Interrogation, media_common, ComputingMethodologies_COMPUTERGRAPHICS
Abstract

International audience; The generation of technical smooth surfaces from a mesh of three-dimensional data points is an important problem in geometric modelling. In this publication we give a survey of some new techniques based on a calculus of variation approach. Apart from the pure construction of these surfaces, the analysis of their quality is equally important in the design and manufacturing process. Generalized focal surfaces are presented here as a new surface interrogation tool.

Published
1993

27. Adaptive modeling and distribution of large natural scenes

Author

Géraldine Morin, Wei Tsang Ooi, Romulus Grigoras, Eckehard Steinbach, Mathias Paulin, Stefanie Hahmann, and Sebastien Mondet

Subjects
Interactivity, Multimedia, Distribution (number theory), Computer science, Materials Chemistry, Software walkthrough, computer.software_genre, computer, Natural (archaeology), ComputingMethodologies_COMPUTERGRAPHICS
Abstract

This thesis deals with the modeling and the interactive streaming of large natural 3D scenes. We aim at providing techniques to allow the remote walkthrough of users in a natural 3D scene ensuring botanical coherency and interactivity.

Published
2009

28. Editorial: Special issue on Geometric Modeling (Dagstuhl 2005)

Author

Stefanie Hahmann, Gerald Farin, Guido Brunnett, and Ron Goldman

Subjects
Reverse engineering, Numerical Analysis, Computer science, Scientific visualization, Point cloud, computer.software_genre, Computer Science Applications, Theoretical Computer Science, Computer graphics, Computational Mathematics, Computer Science::Graphics, Computational Theory and Mathematics, Computer graphics (images), Computer Aided Design, Polygon mesh, Subdivision surface, Geometric modeling, computer, Software, ComputingMethodologies_COMPUTERGRAPHICS
Abstract

Geometric modeling is the branch of Computer Science concerned with the efficient acquisition, representation, manipulation, reconstruction and analysis of threedimensional geometry on a computer. Models and shapes in three dimensions can be represented as splines or subdivision surfaces, as well as by polygonal meshes or point clouds. Applications of geometric modeling cover a wide collection of areas from classical computer aided design, reverse engineering and simulation, to computer graphics, scientific visualization, medical imaging, multimedia and entertainment.

Published
2007

29. Editorial: Geometric Modelling

Author

Ron Goldman, Gerald Farin, Guido Brunnett, and Stefanie Hahmann

Subjects
Computational Mathematics, Numerical Analysis, Engineering drawing, Geometric design, Computational Theory and Mathematics, Computer science, Software, Computer Science Applications, Theoretical Computer Science
Published
2004

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