Browsing by Author "Bénard, Pierre"

Now showing 1 - 5 of 5
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    Coherent Mark-based Stylization of 3D Scenes at the Compositing Stage
    (The Eurographics Association and John Wiley & Sons Ltd., 2021) Garcia, Maxime; Vergne, Romain; Farhat, Mohamed-Amine; Bénard, Pierre; Noûs, Camille; Thollot, Joëlle; Mitra, Niloy and Viola, Ivan
    We present a novel temporally coherent stylized rendering technique working entirely at the compositing stage. We first generate a distribution of 3D anchor points using an implicit grid based on the local object positions stored in a G-buffer, hence following object motion. We then draw splats in screen space anchored to these points so as to be motion coherent. To increase the perceived flatness of the style, we adjust the anchor points density using a fractalization mechanism. Sudden changes are prevented by controlling the anchor points opacity and introducing a new order-independent blending function. We demonstrate the versatility of our method by showing a large variety of styles thanks to the freedom offered by the splats content and their attributes that can be controlled by any G-buffer.
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    Efficient Interpolation of Rough Line Drawings
    (The Eurographics Association and John Wiley & Sons Ltd., 2023) Chen, Jiazhou; Zhu, Xinding; Even, Melvin; Basset, Jean; Bénard, Pierre; Barla, Pascal; Chaine, Raphaëlle; Deng, Zhigang; Kim, Min H.
    In traditional 2D animation, sketches drawn at distant keyframes are used to design motion, yet it would be far too laborintensive to draw all the inbetween frames to fully visualize that motion. We propose a novel efficient interpolation algorithm that generates these intermediate frames in the artist's drawing style. Starting from a set of registered rough vector drawings, we first generate a large number of candidate strokes during a pre-process, and then, at each intermediate frame, we select the subset of those that appropriately conveys the underlying interpolated motion, interpolates the stroke distributions of the key drawings, and introduces a minimum amount of temporal artifacts. In addition, we propose quantitative error metrics to objectively evaluate different stroke selection strategies. We demonstrate the potential of our method on various animations and drawing styles, and show its superiority over competing raster- and vector-based methods.
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    MNPR: A Framework for Real-Time Expressive Non-Photorealistic Rendering of 3D Computer Graphics
    (ACM, 2018) Montesdeoca, Santiago E.; Seah, Hock Soon; Semmo, Amir; Bénard, Pierre; Vergne, Romain; Thollot, Joëlle; Benvenuti, Davide; Aydın, Tunç and Sýkora, Daniel
    We propose a framework for expressive non-photorealistic rendering of 3D computer graphics: MNPR. Our work focuses on enabling stylization pipelines with a wide range of control, thereby covering the interaction spectrum with real-time feedback. In addition, we introduce control semantics that allow crossstylistic art-direction, which is demonstrated through our implemented watercolor, oil and charcoal stylizations. Our generalized control semantics and their style-specific mappings are designed to be extrapolated to other styles, by adhering to the same control scheme. We then share our implementation details by breaking down our framework and elaborating on its inner workings. Finally, we evaluate the usefulness of each level of control through a user study involving 20 experienced artists and engineers in the industry, who have collectively spent over 245 hours using our system. MNPR is implemented in Autodesk Maya and open-sourced through this publication, to facilitate adoption by artists and further development by the expressive research and development community.
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    Non-linear Rough 2D Animation using Transient Embeddings
    (The Eurographics Association and John Wiley & Sons Ltd., 2023) Even, Melvin; Bénard, Pierre; Barla, Pascal; Myszkowski, Karol; Niessner, Matthias
    Traditional 2D animation requires time and dedication since tens of thousands of frames need to be drawn by hand for a typical production. Many computer-assisted methods have been proposed to automatize the generation of inbetween frames from a set of clean line drawings, but they are all limited by a rigid workflow and a lack of artistic controls, which is in the most part due to the one-to-one stroke matching and interpolation problems they attempt to solve. In this work, we take a novel view on those problems by focusing on an earlier phase of the animation process that uses rough drawings (i.e., sketches). Our key idea is to recast the matching and interpolation problems so that they apply to transient embeddings, which are groups of strokes that only exist for a few keyframes. A transient embedding carries strokes between keyframes both forward and backward in time through a sequence of transformed lattices. Forward and backward strokes are then cross-faded using their thickness to yield rough inbetweens. With our approach, complex topological changes may be introduced while preserving visual motion continuity. As demonstrated on state-of-the-art 2D animation exercises, our system provides unprecedented artistic control through the non-linear exploration of movements and dynamics in real-time.
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    Stroke Synthesis for Inbetweening of Rough Line Animations
    (The Eurographics Association, 2020) Chen, Jiazhou; Zhu, Xinding; Bénard, Pierre; Barla, Pascal; Lee, Sung-hee and Zollmann, Stefanie and Okabe, Makoto and Wuensche, Burkhard
    In this paper, we present a stroke synthesis approach for the inbetweening of rough line animations. In pre-process, keyframe strokes are transformed by local perturbation and sliding to generate a number of candidate strokes, and adjacent keyframes are registered together. During inbetweening, candidate strokes are transferred to the intermediate frames and selected based on the desired spatial distribution and length constraints.