Rendu expressif : communication visuelle et abstraction

communication oralecommunication oraleNational audienceno abstrac

Comprendre et améliorer la relation entre simplicité d’interaction et expressivité pour la production d’illustrations

National audienceThis thesis is interested in the relationship between expres- sivity and simplicity in the context of illustrations production. More precisely, it focuses on the design of systems and workflows allowing novice users to produce illustrations in an easier and faster way with a high level of expressivity while still allowing experts users to boost their production performance.Cette thèse s’intéresse à la relation entre expressivité et simplicité dans un contexte de production d’illustrations. Plus précisément, elle se concentre sur le design de sys- tèmes et techniques permettant aux utilisateurs novices de facilement et rapidement produire des illustrations avec un haut niveau d’expression tout en permettant aux utilisateurs experts d’augmenter leur performance

Interactive non-photorealistic rendering

Due to increasing demands of artistic style with Interactive Rate, we propose this review paper as a starting point for any person interested in researching of interactive non-photorealistic rendering. As a simple yet effective means of visual communication, interactive non-photorealistic rendering generates images that are closer to human-drawn than are created by traditional computer graphics techniques with more expressing meaningful visual information. This paper presents taxonomy of interactive non-photorealistic rendering techniques which developed over the past two decades, structured according to the design characteristics and behavior of each technique. Also, it covers the most important algorithms in interactive stylized shade and line drawing, and separately discussing their advantages and disadvantages. The review then concludes with a discussion of the main issues and technical challenges for Interactive Non-Photorealistic Rendering techniques. In addition, this paper discusses the effect of modified phong shading model in order to create toon shading appearance

CAD2Sketch: Generating Concept Sketches from CAD Sequences

International audienceConcept sketches are ubiquitous in industrial design, as they allow designers to quickly depict imaginary 3D objects. To construct their sketches with accurate perspective, designers rely on longstanding drawing techniques, including the use of auxiliary construction lines to identify midpoints of perspective planes, to align points vertically and horizontally, and to project planar curves from one perspective plane to another. We present a method to synthesize such construction lines from CAD sequences. Importantly, our method balances the presence of construction lines with overall clutter, such that the resulting sketch is both well-constructed and readable, as professional designers are trained to do. In addition to generating sketches that are visually similar to real ones, we apply our method to synthesize a large quantity of paired sketches and normal maps, and show that the resulting dataset can be used to train a neural network to infer normals from concept sketches

Programmable style for NPR line-drawing

Jury: Georges-Pierre Bonneau [président](UJF) Victor Ostromoukhov [rapporteur](Universite de Montreal) Thomas Strothotte [rapporteur](Université de Magdeburg) Fredo Durand [examinateur](MIT)This dissertation deals with the rendering of ``non-photorealistic'' illustrations (imitating drawings or paintings for instance) from 3D scenes. Abstraction or stylization enhance this type of rendering with communicative, aesthetic and expressive qualities that distinguish it from usual image synthesis. Our goals is to provide the user with a flexible control over the style of the non-photorealistic rendering and, also, to propose a style formulation that allows the reuse of the same style to render different 3D scenes. We chose a programmable approach that relies on the assumption that style attributes (color, thickness, ...) are chosen depending on generic information from the scene (line charasteristics, depth discontinuity, ...), and takes inspiration from procedural approaches (such as Pixar Renderman). The idea consists in expressing a style as a set of procedures specifying the relations between attributes and information: The user ``programs'' a style sheet that can be used to render several different 3D scenes or several images from an animated sequence. This approach is the first one to offer both flexible control over the style of the rendering and a reusable formulation of that style.Cette thèse s'intéresse à la génération d'illustrations "non-photoréalistes" (imitant par exemple des dessins ou des peintures) à partir de scènes 3D. L'abstraction ou la stylisation apportent à ce type de rendu des qualités communicatives, esthétiques et expressives qui le distinguent de la synthèse d'images classique. Les objectifs sont, d'une part, de fournir à l'utilisateur un contrôle flexible sur le style du rendu non-photoréaliste et, d'autre part, de proposer une formulation du style qui en permette la réutilisation pour le rendu de différentes scènes 3D. Nous avons choisi d'adopter une approche programmable qui s'appuie sur le postulat selon lequel les attributs de style (couleur, épaisseur, ...) sont choisis en fonction d'informations génériques de la scène (nature des lignes, discontinuité en profondeur, ...), et s'inspire des approches procédurales (telles que Pixar Renderman). L'idée consiste à exprimer un style comme un ensemble de procédures spécifiant les relations attributs/informations : l'utilisateur "programme" une feuille de style qui peut ensuite être utilisée pour le rendu de plusieurs scènes 3D différentes ou de plusieurs images d'une séquence animée. Cette approche est la première à offrir à la fois un contrôle flexible sur le style du rendu et une formulation réutilisable de ce style

Programmable style for NPR line-drawing

Jury: Georges-Pierre Bonneau [président](UJF) Victor Ostromoukhov [rapporteur](Universite de Montreal) Thomas Strothotte [rapporteur](Université de Magdeburg) Fredo Durand [examinateur](MIT)This dissertation deals with the rendering of ``non-photorealistic'' illustrations (imitating drawings or paintings for instance) from 3D scenes. Abstraction or stylization enhance this type of rendering with communicative, aesthetic and expressive qualities that distinguish it from usual image synthesis. Our goals is to provide the user with a flexible control over the style of the non-photorealistic rendering and, also, to propose a style formulation that allows the reuse of the same style to render different 3D scenes. We chose a programmable approach that relies on the assumption that style attributes (color, thickness, ...) are chosen depending on generic information from the scene (line charasteristics, depth discontinuity, ...), and takes inspiration from procedural approaches (such as Pixar Renderman). The idea consists in expressing a style as a set of procedures specifying the relations between attributes and information: The user ``programs'' a style sheet that can be used to render several different 3D scenes or several images from an animated sequence. This approach is the first one to offer both flexible control over the style of the rendering and a reusable formulation of that style.Cette thèse s'intéresse à la génération d'illustrations "non-photoréalistes" (imitant par exemple des dessins ou des peintures) à partir de scènes 3D. L'abstraction ou la stylisation apportent à ce type de rendu des qualités communicatives, esthétiques et expressives qui le distinguent de la synthèse d'images classique. Les objectifs sont, d'une part, de fournir à l'utilisateur un contrôle flexible sur le style du rendu non-photoréaliste et, d'autre part, de proposer une formulation du style qui en permette la réutilisation pour le rendu de différentes scènes 3D. Nous avons choisi d'adopter une approche programmable qui s'appuie sur le postulat selon lequel les attributs de style (couleur, épaisseur, ...) sont choisis en fonction d'informations génériques de la scène (nature des lignes, discontinuité en profondeur, ...), et s'inspire des approches procédurales (telles que Pixar Renderman). L'idée consiste à exprimer un style comme un ensemble de procédures spécifiant les relations attributs/informations : l'utilisateur "programme" une feuille de style qui peut ensuite être utilisée pour le rendu de plusieurs scènes 3D différentes ou de plusieurs images d'une séquence animée. Cette approche est la première à offrir à la fois un contrôle flexible sur le style du rendu et une formulation réutilisable de ce style

Programmable Style for NPR Line Drawing

International audienceThis paper introduces a programmable approach to non-photorealistic line drawing from 3D models, inspired by programmable shaders in traditional rendering. We propose a new image creation model where all operations are controlled through user-defined procedures. A view map describing all relevant support lines in the drawing and their topological arrangement is first created from the 3D model; a number of style modules operate on this map, by procedurally selecting, chaining or splitting lines, before creating strokes and assigning drawing attributes. The resulting drawing system permits flexible control of all elements of drawing style: first, different style modules can be applied to different types of lines in a view; second, the topology and geometry of strokes are entirely controlled from the programmable modules; and third, stroke attributes are assigned procedurally and can be correlated at will with various scene or view properties. Finally, we propose new density control strategies where strokes can be adapted or omitted to avoid visual clutter. We illustrate the components of our system and show how style modules successfully capture stylized visual characteristics that can be applied across a wide range of models