Browsing by Author "Giannini, Franca"

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    A 3D CAD Assembly Benchmark
    (The Eurographics Association, 2019) Lupinetti, Katia; Giannini, Franca; monti, marina; PERNOT, Jean-Philippe; Biasotti, Silvia and Lavoué, Guillaume and Veltkamp, Remco
    Evaluating the effectiveness of the systems for the retrieval of 3D assembly models is not trivial. CAD assembly models can be considered similar according to different criteria and at different levels (i.e. globally or partially). Indeed, besides the shape criterion, CAD assembly models have further characteristic elements, such as the mutual position of parts, or the type of connecting joint. Thus, when retrieving 3D models, these characteristics can match in the entire model (globally) or just in local subparts (partially). The available 3D model repositories do not include complex CAD assembly models and, generally, they are suitable to evaluate one characteristic at a time and neglecting important properties in the evaluation of assembly similarity. In this paper, we present a benchmark for the evaluation of content-retrieval systems of 3D assembly models. A crucial feature of this benchmark regards its ability to consider the various aspects characterizing the models of mechanical assemblies.
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    Assembly Retrieval Results Inspection in Immersive Environment
    (The Eurographics Association, 2019) Lupinetti, Katia; Bonino, Brigida; Giannini, Franca; monti, marina; Fusiello, Andrea and Bimber, Oliver
    This poster presents a research aimed at supporting the browsing through the results of an assembly retrieval system by exploiting Virtual Reality technologies. To support the users' understanding during the assessing of the similarities of 3D assembly models, the proposed system exploits the three-dimensionality of the space to locate the retrieved models distributing them according to their dissimilarity to the model used as query. It also allows the users to interact with assemblies through voice and gesture commands, which resemble gestures well-established in touch user interfaces. Through them, users can see correspondences between assemblies, disassemble and re-assemble 3D digital models, such that it is possible a better inspection of the assembly components that is the first step for the development of systems allowing for their modifications and combinations.
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    Towards the Fitting of Parametric 2D Sketches and 3D CAD Models to Point Clouds of Digitized Assemblies for Reverse Engineering
    (The Eurographics Association, 2019) SHAH, Ghazanfar Ali; Giannini, Franca; monti, marina; Polette, Arnaud; PERNOT, Jean-Philippe; Fusiello, Andrea and Bimber, Oliver
    Following commonly used reverse engineering techniques, it is very difficult to reconstruct editable CAD parts or assemblies that can later be used and modified in the Product Development Process (PDP). Traditional methods follow a sequential time-consuming patch-by-patch reconstruction strategy with cumbersome procedures in which designers usually have to face many issues (e.g. decomposition in patches, trimming and connection of the patches), and generally producing ''dead'' models that cannot be later modified as needed. This paper describes a new reverse engineering technique that allows fitting of parametric CAD parts or an assembly to a reference point cloud to be reconstructed. The proposed fitting method can also be applied to 2D configurations to adapt a parametric 2D sketch to a 2D point cloud section. The idea is to use a parametric CAD model or a parametric 2D sketch in an optimization algorithm allowing their perfect fitting into the point cloud of a scanned mechanical assembly for efficient reconstruction of good quality CAD models. Some well-known algorithms like ICP are also used to derive the orientation and position of pre-arranged CAD model or 2D sketch throughout the fitting process. Both global and local fittings are possible. The consistency of the CAD models is ensured by a modeler which updates the CAD models or 2D sketch according to the iterative dimensional modifications. The evaluation of the proposed approach is performed using as-scanned virtually generated point clouds which incorporate several artifacts that would appear using a real scanner. This technique allows for the comparison between the dimensions of the fitted parts and the ones of the parts used to generate the point clouds.