Modeling Symmetric Developable Surfaces from a Single Photo

National audienceWe propose a method to reconstruct 3D developable surfaces from a single 2D drawing traced and annotatedover a side-view photo of a partially symmetrical object. Our reconstruction algorithm combines symmetry andorthogonality shapes cues within a unified optimization framework that solves for the 3D position of the Beziercontrol points of the drawn curves while being tolerant to drawing inaccuracy and perspective distortions. We thenrely on existing surface optimization methods to produce a developable surface that interpolates our 3D curves.Our method is particularly well suited for the modeling and fabrication of fashion items as it converts the inputdrawing into flattened developable patterns ready for sewing

Interactive procedural simulation of paper tearing with sound

International audienceWe present a phenomenological model for the real-time simulation of paper tearing and sound. The model uses as input rotations of the hand along with the index and thumb of left and right hands to drive the position and orientation of two regions of a sheet of paper. The motion of the hands produces a cone shaped deformation of the paper and guides the formation and growth of the tear. We create a model for the direction of the tear based on empirical observation, and add detail to the tear with a directed noise model. Furthermore, we present a procedural sound synthesis method to produce tearing sounds during interaction. We show a variety of paper tearing examples and discuss applications and limitations

Towards a visual language for animated paintings

Groupe de travail "Rendu" du GdR IG-RVNational audienc

Automatic Intermediate Frames for Stroke-based Animation

National audienceCreating a 2D animation with visible strokes is a tedious and time consuming task for an artist. Computer aided animation usually focus on cartoon stylized rendering, or is built from an automatic process as 3D animations stylization, loosing the painterly look and feel of hand made animation. We propose to simplify the creation of stroke-based animations: from a set of key frames, our methods automatically generates intermediate frames with coherent motion. Each intermediate frame looks as it could have been drawn by an artist, using the same high level stroke based representation as key frame, and in succession they display the subtle temporal incoherence usually found in hand-made animations

Stroke based Painterly Inbetweening

International audienceCreating a 2D animation with visible strokes is a tedious and time consuming task for an artist. Computer aided animation usually focus on cartoon stylized rendering, or is built from an automatic process as 3D animations stylization, loosing the painterly look and feel of hand made animation. We propose to simplify the creation of stroke-based animations: from a set of key frames, our methods automatically generates intermediate frames to depict the animation. Each intermediate frame looks as it could have been drawn by an artist, using the same high level stroke based representation as key frame, and in succession they display the subtle temporal incoherence usually found in handmade animations

Towards developable products from a sketch

International audienceDevelopable surfaces are surfaces that can be unfolded onto a plane, without distortion, and are widely used in industry We propose an end-to-end system for the interactive modeling of developable objects from a single annotated photo, restricted to the case of symmetrical objects made by assemblies of planes and generalized cylinders. Our method is in two parts : we first analyze the 2D annotated photo to extract the location of symmetric points and the rulings of the cylindrical regions. Then we use this 2D information in a global system to lift the shape of the object in 3D

Fashion Transfer: Dressing 3D Characters from Stylized Fashion Sketches

International audienceFashion 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

Patterns from Photograph: Reverse-Engineering Developable Products

International audienceDevelopable 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