1,720,962 research outputs found
A functional skeleton transfer
No full textThe animation community has spent significant effort trying to ease rigging procedures. This is necessitated because the increasing availability of 3D data makes manual rigging infeasible. However, object animations involve understanding elaborate geometry and dynamics, and such knowledge is hard to infuse even with modern data-driven techniques. Automatic rigging methods do not provide adequate control and cannot generalize in the presence of unseen artifacts. As an alternative, one can design a system for one shape and then transfer it to other objects. In previous work, this has been implemented by solving the dense point-to-point correspondence problem. Such an approach requires a significant amount of supervision, often placing hundreds of landmarks by hand. This paper proposes a functional approach for skeleton transfer that uses limited information and does not require a complete match between the geometries. To do so, we suggest a novel representation for the skeleton properties, namely the functional regressor, which is compact and invariant to different discretizations and poses. We consider our functional regressor a new operator to adopt in intrinsic geometry pipelines for encoding the pose information, paving the way for several new applications. We numerically stress our method on a large set of different shapes and object classes, providing qualitative and numerical evaluations of precision and computational efficiency. Finally, we show a preliminar transfer of the complete rigging scheme, introducing a promising direction for future explorations
GIM3D plus: A labeled 3D dataset to design data-driven solutions for dressed humans
Full text linkSegmentation and classification of clothes in real 3D data are particularly challenging due to the extreme variation of their shapes, even among the same cloth category, induced by the underlying human subject. Several data-driven methods try to cope with this problem. Still, they must face the lack of available data to generalize to various real-world instances. For this reason, we present GIM3D plus (Garments In Motion 3D plus), a synthetic dataset of clothed 3D human characters in different poses. A physical simulation of clothes generates the over 5000 3D models in this dataset with different fabrics, sizes, and tightness, using animated human avatars representing different subjects in diverse poses. Our dataset comprises single meshes created to simulate 3D scans, with labels for the separate clothes and the visible body parts. We also provide an evaluation of the use of GIM3D plus as a training set on garment segmentation and classification tasks using state-of-the-art data-driven methods for both meshes and point clouds
Intrinsic/extrinsic embedding for functional remeshing of 3D shapes
No full text3D acquisition pipeline delivers 3D digital models accurately representing real-world objects, improving the geometric accuracy and realism of virtual reconstructions. However, even after intensive clean-up, the captured models fall short of many of the requirements imposed by the downstream application, such as video-games, virtual reality, digital movies, etc. Often, the captured 3D model can only serve as a starting point for a cascade of subsequent phases, by either digital artists or geometry processing algorithms, such as a complete remeshing (or retopology), surface parameterization, and skinning for animation. In contrast, we propose a novel remeshing-by-matching approach, where we automatically combine the accurate 3D geometry of the captured model with the tessellation of a target pre-existing template which already satisfies all the professional requirements. At the core of this process, there is a matching strategy based on the functional mapping framework. To this end, we introduce a new set of basis functions designed for this context: termed Coordinates Manifold Harmonics (CMH). We evaluate this strategy (quantitatively and qualitatively) over models of different classes, obtaining a favourable comparison with existing methods
A Modeling-by-matching approach for clothed human animation
No full textThe realization of animated 3D characters has always been expensive in terms of resources and time. Animators spend months in the creation of realistic 3D shapes to be animated. Obtaining an automatic method for building a high-quality shape with the desired characteristics for the animation is a challenging problem. In the last decade, the availability of 3D scanning devices, though, is highly increased, and the cost is progressively decreased. Acquiring a 3D model from the real world has become within everyone's reach. The most significant disadvantage of these methods is the noise and the irregularity of the 3d meshes obtained from the acquisition, so the interest by researchers in algorithms to handle and clean this type of data has grown highly. In this thesis, I present a complete pipeline to combine realistic geometries acquired from the real world and the desired properties to create an animation-ready 3D model using a modeling-by-matching technique. The idea is to provide a robust matching to transfer all the information we need for a proper animation from an artist-defined 3D model to a 3D scan of a clothed human. First, we present a new 3D dataset for clothed human segmentation and garment classification. This step of the pipeline divides the separate layers of the input 3D scans and classifies the typology of the outfit of the model, facilitating the following passages of the pipeline. Then, we explore a new method for skeleton transfer from one shape to another by using a novel approach that lets us transfer the position of the joints composing the skeleton building a spectral regressor. In addition, by using the transferred skeleton, we solve an optimization problem to find the 3D rotations of the pose of the input model, which is fundamental for the transfer of an animation sequence. Finally, we will show a robust method based to obtain a correspondence between shapes that led us to perform a tessellation transfer on both humans and garments. All these three passages are based on the functional maps framework, the process of finding matches on functions defined on the surfaces. This matching approach is efficient and flexible and lets us be independent by the discretization, the details on the surfaces, and the pose of the shapes involved. With such fundamental steps, we obtain a fully automatic pipeline to provide an animated 3D setup starting from a single 3D scan, providing new approaches to modeling and animation. All the data and the code we produced are freely available for research purposes
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A Modeling-by-matching approach for clothed human animation
No full textThe realization of animated 3D characters has always been expensive in terms of resources and time. Animators spend months in the creation of realistic 3D shapes to be animated. Obtaining an automatic method for building a high-quality shape with the desired characteristics for the animation is a challenging problem. In the last decade, the availability of 3D scanning devices, though, is highly increased, and the cost is progressively decreased. Acquiring a 3D model from the real world has become within everyone’s reach. The most significant disadvantage of these methods is the noise and the irregularity of the 3d meshes obtained from the acquisition, so the interest by researchers in algorithms to handle and clean this type of data has grown highly. In this thesis, I present a complete pipeline to combine realistic geometries acquired from the real world and the desired properties to create an animation-ready 3D model using a modeling-bymatching technique. The idea is to provide a robust matching to transfer all the information we need for a proper animation from an artist-defined 3D model to a 3D scan of a clothed human. First, we present a new 3D dataset for clothed human segmentation and garment classification. This step of the pipeline divides the separate layers of the input 3D scans and classifies the typology of the outfit of the model, facilitating the following passages of the pipeline. Then, we explore a new method for skeleton transfer from one shape to another by using a novel approach that lets us transfer the position of the joints composing the skeleton building a spectral regressor. In addition, by using the transferred skeleton, we solve an optimization problem to find the 3D rotations of the pose of the input model, which is fundamental for the transfer of an animation sequence. Finally, we will show a robust method based to obtain a correspondence between shapes that led us to performa tessellation transfer on both humans and garments. All these three passages are based on the functional maps framework, the process of finding matches on functions defined on the surfaces. This matching approach is efficient and flexible and lets us be independent by the discretization, the details on the surfaces, and the pose of the shapes involved. With such fundamental steps, we obtain a fully automatic pipeline to provide an animated 3D setup starting from a single 3D scan, providing new approaches to modeling and animation. All the data and the code we produced are freely available for research purposes
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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