Volume 43 (2024)

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Browsing Volume 43 (2024) by Subject "Applied computing"

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    Entropy-driven Progressive Compression of 3D Point Clouds
    (The Eurographics Association and John Wiley & Sons Ltd., 2024) Zampieri, Armand; Delarue, Guillaume; Bakr, Nachwa Abou; Alliez, Pierre; Hu, Ruizhen; Lefebvre, Sylvain
    3D point clouds stand as one of the prevalent representations for 3D data, offering the advantage of closely aligning with sensing technologies and providing an unbiased representation of a measured physical scene. Progressive compression is required for real-world applications operating on networked infrastructures with restricted or variable bandwidth. We contribute a novel approach that leverages a recursive binary space partition, where the partitioning planes are not necessarily axis-aligned and optimized via an entropy criterion. The planes are encoded via a novel adaptive quantization method combined with prediction. The input 3D point cloud is encoded as an interlaced stream of partitioning planes and number of points in the cells of the partition. Compared to previous work, the added value is an improved rate-distortion performance, especially for very low bitrates. The latter are critical for interactive navigation of large 3D point clouds on heterogeneous networked infrastructures.
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    Freeform Shape Fabrication by Kerfing Stiff Materials
    (The Eurographics Association and John Wiley & Sons Ltd., 2024) Speetzen, Nils; Kobbelt, Leif; Bermano, Amit H.; Kalogerakis, Evangelos
    Fast, flexible, and cost efficient production of 3D models from 2D material sheets is a key component in digital fabrication and prototyping. In order to achieve high quality approximations of freeform shapes, a common set of methods aim to produce bendable 2D cutouts that are then assembled. So far bent surfaces are achieved automatically by computing developable patches of the input surface, e.g. in the context of papercraft. For stiff materials such as medium-density fibreboard (MDF) or plywood, the 2D cutouts require the application of additional cutting patterns (''kerfing'') to make them bendable. Such kerf patterns are commonly constructed with considerable user input, e.g. in architectural design. We propose a fully automatic method that produces kerfed cutouts suitable for the assembly of freeform shapes from stiff material sheets. By exploring the degrees of freedom emerging from the choice of bending directions, the creation of box joints at the patch boundaries as well as the application of kerf cuts with adaptive density, our method is able to achieve a high quality approximation of the input.
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    Unfolding via Mesh Approximation using Surface Flows
    (The Eurographics Association and John Wiley & Sons Ltd., 2024) Zawallich, Lars; Pajarola, Renato; Bermano, Amit H.; Kalogerakis, Evangelos
    Manufacturing a 3D object by folding from a 2D material is typically done in four steps: 3D surface approximation, unfolding the surface into a plane, printing and cutting the outline of the unfolded shape, and refolding it to a 3D object. Usually, these steps are treated separately from each other. In this work we jointly address the first two pipeline steps by allowing the 3D representation to smoothly change while unfolding. This way, we increase the chances to overcome possible ununfoldability issues. To join the two pipeline steps, our work proposes and combines different surface flows with a Tabu Unfolder. We empirically investigate the effects that different surface flows have on the performance as well as on the quality of the unfoldings. Additionally, we demonstrate the ability to solve cases by approximation which comparable algorithms either have to segment or can not solve at all.