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Paolo Cignoni
ISTI, CNR, via G. Moruzzi 1, Pisa 56124, Italy

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Journal article
Published: 21 August 2021 in Structures
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This paper introduces an integrated computational design framework for the design and realization of arbitrarily-curved bending-active architectural structures. The developed framework consists of a series of methods that enable the production of a complex 3D structures composed of a set of flat 2D panels whose mechanical properties are locally tuned by varying the shape of embedded spiraling patterns. The resulting panels perform as variable stiffness elements, and they are optimized to match a desired target shape once assembled together. The presented framework includes all the steps for the physical delivery of architectural objects, including conception, static assessment, and digital fabrication. The developed framework has been applied to an architectural scale prototype, which demonstrates the potential of integrating architectural design, computational simulation, structural engineering, and digital fabrication, opening up several possible novel applications in the building sector.

ACS Style

Francesco Laccone; Luigi Malomo; Nico Pietroni; Paolo Cignoni; Tim Schork. Integrated computational framework for the design and fabrication of bending-active structures made from flat sheet material. Structures 2021, 34, 979 -994.

AMA Style

Francesco Laccone, Luigi Malomo, Nico Pietroni, Paolo Cignoni, Tim Schork. Integrated computational framework for the design and fabrication of bending-active structures made from flat sheet material. Structures. 2021; 34 ():979-994.

Chicago/Turabian Style

Francesco Laccone; Luigi Malomo; Nico Pietroni; Paolo Cignoni; Tim Schork. 2021. "Integrated computational framework for the design and fabrication of bending-active structures made from flat sheet material." Structures 34, no. : 979-994.

Journal article
Published: 03 June 2021 in Remote Sensing
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Virtual reality (VR) technologies have become more and more affordable and popular in the last five years thanks to hardware and software advancements. A critical issue for these technologies is finding paradigms that allow user interactions in ways that are as similar as possible to the real world, bringing physicality into the experience. Current literature has shown, with different experiments, that the mapping of real objects in virtual reality alongside haptic feedback significantly increases the realism of the experience and user engagement, leading to augmented virtuality. In this paper, we present a system to improve engagement in a VR experience using inexpensive, physical, and sensorized copies of real artefacts made with cheap 3D fabrication technologies. Based on a combination of hardware and software components, the proposed system gives the user the possibility to interact with the physical replica in the virtual environment and to see the appearance of the original cultural heritage artefact. In this way, we overcome one of the main limitations of mainstream 3D fabrication technologies: a faithful appearance reproduction. Using a consumer device for the real-time hand tracking and a custom electronic controller for the capacitive touch sensing, the system permits the creation of augmented experiences where the user with their hands can change the virtual appearance of the real replica object using a set of personalization actions selectable from a physical 3D-printed palette.

ACS Style

Gianpaolo Palma; Sara Perry; Paolo Cignoni. Augmented Virtuality Using Touch-Sensitive 3D-Printed Objects. Remote Sensing 2021, 13, 2186 .

AMA Style

Gianpaolo Palma, Sara Perry, Paolo Cignoni. Augmented Virtuality Using Touch-Sensitive 3D-Printed Objects. Remote Sensing. 2021; 13 (11):2186.

Chicago/Turabian Style

Gianpaolo Palma; Sara Perry; Paolo Cignoni. 2021. "Augmented Virtuality Using Touch-Sensitive 3D-Printed Objects." Remote Sensing 13, no. 11: 2186.

3d and beyond
Published: 01 May 2021 in Computer Graphics Forum
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We propose a method to improve an existing parametrization (UV-map layout) of a textured 3D model, targeted explicitly at alleviating typical defects afflicting models generated with automatic photo-reconstruction tools from real-world objects. This class of 3D data is becoming increasingly important thanks to the growing popularity of reliable, ready-to-use photogrammetry software packages. The resulting textured models are richly detailed, but their underlying parametrization typically falls short of many practical requirements, particularly exhibiting excessive fragmentation and consequent problems. Producing a completely new UV-map, with standard parametrization techniques, and then resampling a new texture image, is often neither practical nor desirable for at least two reasons: first, these models have characteristics (such as inconsistencies, high resolution) that make them unfit for automatic or manual parametrization; second, the required resampling leads to unnecessary signal degradation because this process is unaware of the original texel densities. In contrast, our method improves the existing UV-map instead of replacing it, balancing the reduction of the map fragmentation with signal degradation due to resampling, while also avoiding oversampling of the original signal. The proposed approach is fully automatic and extensively tested on a large benchmark of photo-reconstructed models; quantitative evaluation evidences a drastic and consistent improvement of the mappings.

ACS Style

Andrea Maggiordomo; Paolo Cignoni; Marco Tarini. Texture Defragmentation for Photo‐Reconstructed 3D Models. Computer Graphics Forum 2021, 40, 65 -78.

AMA Style

Andrea Maggiordomo, Paolo Cignoni, Marco Tarini. Texture Defragmentation for Photo‐Reconstructed 3D Models. Computer Graphics Forum. 2021; 40 (2):65-78.

Chicago/Turabian Style

Andrea Maggiordomo; Paolo Cignoni; Marco Tarini. 2021. "Texture Defragmentation for Photo‐Reconstructed 3D Models." Computer Graphics Forum 40, no. 2: 65-78.

Journal article
Published: 09 October 2020 in Computer Aided Geometric Design
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We are witnessing a proliferation of textured 3D models captured from the real world with automatic photo-reconstruction tools by people and professionals without a proper technical background in computer graphics. Digital 3D models of this class come with a unique set of characteristics and defects – especially concerning their parametrization – setting them starkly apart from 3D models originating from other, more traditional, sources. We study this class of 3D models by collecting a significant number of representatives and quantitatively evaluating their quality according to several metrics. These include a new invariant metric we carefully design to assess the amount of fragmentation of the UV map, which is one of the main weaknesses potentially hindering the usability of these models. Our results back the widely shared notion that models of this new class are still not fit for direct use in downstream applications (such as videogames), and require challenging processing steps. Regrettably, existing automatic geometry processing tools are not always up to the task: for example, we verify that the available tools for UV optimization often fail due to mesh inconsistencies, geometric and topological noise, excessive resolution, or other factors; moreover, even when an output is produced, it rarely represents a significant improvement over the input (according to the aforementioned measures). Therefore, we argue that further advancements are required by the computer graphics and geometry processing communities specifically targeted at this class of models. Towards this goal, we share the models we collected in this study as a new public repository, Real-World Textured Things (RWTT), intended as a benchmark to systematic field-test and compare future algorithms. RWTT consists of 568 carefully selected textured 3D models representative of the most popular photo-reconstruction tools currently available. We also provide a web interface to browse the dataset by the metadata we collected during our experiments and a tool, TexMetro, to compute the same set of measures on generic UV mapped datasets.

ACS Style

Andrea Maggiordomo; Federico Ponchio; Paolo Cignoni; Marco Tarini. Real-World Textured Things: A repository of textured models generated with modern photo-reconstruction tools. Computer Aided Geometric Design 2020, 83, 101943 .

AMA Style

Andrea Maggiordomo, Federico Ponchio, Paolo Cignoni, Marco Tarini. Real-World Textured Things: A repository of textured models generated with modern photo-reconstruction tools. Computer Aided Geometric Design. 2020; 83 ():101943.

Chicago/Turabian Style

Andrea Maggiordomo; Federico Ponchio; Paolo Cignoni; Marco Tarini. 2020. "Real-World Textured Things: A repository of textured models generated with modern photo-reconstruction tools." Computer Aided Geometric Design 83, no. : 101943.

Journal article
Published: 22 September 2020 in Remote Sensing
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The semantic segmentation of underwater imagery is an important step in the ecological analysis of coral habitats. To date, scientists produce fine-scale area annotations manually, an exceptionally time-consuming task that could be efficiently automatized by modern CNNs. This paper extends our previous work presented at the 3DUW’19 conference, outlining the workflow for the automated annotation of imagery from the first step of dataset preparation, to the last step of prediction reassembly. In particular, we propose an ecologically inspired strategy for an efficient dataset partition, an over-sampling methodology targeted on ortho-imagery, and a score fusion strategy. We also investigate the use of different loss functions in the optimization of a Deeplab V3+ model, to mitigate the class-imbalance problem and improve prediction accuracy on coral instance boundaries. The experimental results demonstrate the effectiveness of the ecologically inspired split in improving model performance, and quantify the advantages and limitations of the proposed over-sampling strategy. The extensive comparison of the loss functions gives numerous insights on the segmentation task; the Focal Tversky, typically used in the context of medical imaging (but not in remote sensing), results in the most convenient choice. By improving the accuracy of automated ortho image processing, the results presented here promise to meet the fundamental challenge of increasing the spatial and temporal scale of coral reef research, allowing researchers greater predictive ability to better manage coral reef resilience in the context of a changing environment.

ACS Style

Gaia Pavoni; Massimiliano Corsini; Marco Callieri; Giuseppe Fiameni; Clinton Edwards; Paolo Cignoni. On Improving the Training of Models for the Semantic Segmentation of Benthic Communities from Orthographic Imagery †. Remote Sensing 2020, 12, 3106 .

AMA Style

Gaia Pavoni, Massimiliano Corsini, Marco Callieri, Giuseppe Fiameni, Clinton Edwards, Paolo Cignoni. On Improving the Training of Models for the Semantic Segmentation of Benthic Communities from Orthographic Imagery †. Remote Sensing. 2020; 12 (18):3106.

Chicago/Turabian Style

Gaia Pavoni; Massimiliano Corsini; Marco Callieri; Giuseppe Fiameni; Clinton Edwards; Paolo Cignoni. 2020. "On Improving the Training of Models for the Semantic Segmentation of Benthic Communities from Orthographic Imagery †." Remote Sensing 12, no. 18: 3106.

Original paper
Published: 14 July 2020 in Applied Geomatics
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Since the early days of the low-cost camera development, the collection of visual data has become a common practice in the underwater monitoring field. Nevertheless, video and image sequences are a trustworthy source of knowledge that remains partially untapped. Human-based image analysis is a time-consuming task that creates a bottleneck between data collection and extrapolation. Nowadays, the annotation of biologically meaningful information from imagery can be efficiently automated or accelerated by convolutional neural networks (CNN). Presenting our case studies, we offer an overview of the potentialities and difficulties of accurate automatic recognition and segmentation of benthic species. This paper focuses on the application of deep learning techniques to multi-view stereo reconstruction by-products (registered images, point clouds, ortho-projections), considering the proliferation of these techniques among the marine science community. Of particular importance is the need to semantically segment imagery in order to generate demographic data vital to understand and explore the changes happening within marine communities.

ACS Style

G. Pavoni; M. Corsini; N. Pedersen; V. Petrovic; P. Cignoni. Challenges in the deep learning-based semantic segmentation of benthic communities from Ortho-images. Applied Geomatics 2020, 13, 131 -146.

AMA Style

G. Pavoni, M. Corsini, N. Pedersen, V. Petrovic, P. Cignoni. Challenges in the deep learning-based semantic segmentation of benthic communities from Ortho-images. Applied Geomatics. 2020; 13 (1):131-146.

Chicago/Turabian Style

G. Pavoni; M. Corsini; N. Pedersen; V. Petrovic; P. Cignoni. 2020. "Challenges in the deep learning-based semantic segmentation of benthic communities from Ortho-images." Applied Geomatics 13, no. 1: 131-146.

Optimization for fabrication
Published: 01 May 2020 in Computer Graphics Forum
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We propose a method for the automatic segmentation of 3D objects into parts which can be individually 3D printed and then reassembled by preserving the visual quality of the final object. Our technique focuses on minimizing the surface affected by supports, decomposing the object into multiple parts whose printing orientation is automatically chosen. The segmentation reduces the visual impact on the fabricated model producing non‐planar cuts that adapt to the object shape. This is performed by solving an optimization problem that balances the effects of supports and cuts, while trying to place both in occluded regions of the object surface. To assess the practical impact of the solution, we show a number of segmented, 3D printed and reassembled objects.

ACS Style

I. Filoscia; T. Alderighi; D. Giorgi; L. Malomo; M. Callieri; P. Cignoni. Optimizing Object Decomposition to Reduce Visual Artifacts in 3D Printing. Computer Graphics Forum 2020, 39, 423 -434.

AMA Style

I. Filoscia, T. Alderighi, D. Giorgi, L. Malomo, M. Callieri, P. Cignoni. Optimizing Object Decomposition to Reduce Visual Artifacts in 3D Printing. Computer Graphics Forum. 2020; 39 (2):423-434.

Chicago/Turabian Style

I. Filoscia; T. Alderighi; D. Giorgi; L. Malomo; M. Callieri; P. Cignoni. 2020. "Optimizing Object Decomposition to Reduce Visual Artifacts in 3D Printing." Computer Graphics Forum 39, no. 2: 423-434.

Global illumination
Published: 01 October 2019 in Computer Graphics Forum
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Acquired 3D point clouds make possible quick modeling of virtual scenes from the real world. With modern 3D capture pipelines, each point sample often comes with additional attributes such as normal vector and color response. Although rendering and processing such data has been extensively studied, little attention has been devoted using the light transport hidden in the recorded per‐sample color response to relight virtual objects in visual effects (VFX) look‐dev or augmented reality (AR) scenarios. Typically, standard relighting environment exploits global environment maps together with a collection of local light probes to reflect the light mood of the real scene on the virtual object. We propose instead a unified spatial approximation of the radiance and visibility relationships present in the scene, in the form of a colored point cloud. To do so, our method relies on two core components: High Dynamic Range (HDR) expansion and real‐time Point‐Based Global Illumination (PBGI). First, since an acquired color point cloud typically comes in Low Dynamic Range (LDR) format, we boost it using a single HDR photo exemplar of the captured scene that can cover part of it. We perform this expansion efficiently by first expanding the dynamic range of a set of renderings of the point cloud and then projecting these renderings on the original cloud. At this stage, we propagate the expansion to the regions not covered by the renderings or with low‐quality dynamic range by solving a Poisson system. Then, at rendering time, we use the resulting HDR point cloud to relight virtual objects, providing a diffuse model of the indirect illumination propagated by the environment. To do so, we design a PBGI algorithm that exploits the GPU's geometry shader stage as well as a new mipmapping operator, tailored for G‐buffers, to achieve real‐time performances. As a result, our method can effectively relight virtual objects exhibiting diffuse and glossy physically‐based materials in real time. Furthermore, it accounts for the spatial embedding of the object within the 3D environment. We evaluate our approach on manufactured scenes to assess the error introduced at every step from the perfect ground truth. We also report experiments with real captured data, covering a range of capture technologies, from active scanning to multiview stereo reconstruction.

ACS Style

Manuele Sabbadin; Gianpaolo Palma; Francesco Banterle; Tamy Boubekeur; Paolo Cignoni. High Dynamic Range Point Clouds for Real‐Time Relighting. Computer Graphics Forum 2019, 38, 513 -525.

AMA Style

Manuele Sabbadin, Gianpaolo Palma, Francesco Banterle, Tamy Boubekeur, Paolo Cignoni. High Dynamic Range Point Clouds for Real‐Time Relighting. Computer Graphics Forum. 2019; 38 (7):513-525.

Chicago/Turabian Style

Manuele Sabbadin; Gianpaolo Palma; Francesco Banterle; Tamy Boubekeur; Paolo Cignoni. 2019. "High Dynamic Range Point Clouds for Real‐Time Relighting." Computer Graphics Forum 38, no. 7: 513-525.

Major revision from eurographics conference
Published: 09 July 2019 in Computer Graphics Forum
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We propose an optimization algorithm for the design of post‐tensioned architectural shell structures, composed of triangular glass panels, in which glass has a load‐bearing function. Due to its brittle nature, glass can fail when it is subject to tensile forces. Hence, we enrich the structure with a cable net, which is specifically designed to post‐tension the shell, relieving the underlying glass structure from tension. We automatically derive an optimized cable layout, together with the appropriate pre‐load of each cable. The method is driven by a physically based static analysis of the shell subject to its service load. We assess our approach by applying non‐linear finite element analysis to several real‐scale application scenarios. Such a method of cable tensioning produces glass shells that are optimized from the material usage viewpoint since they exploit the high compression strength of glass. As a result, they are lightweight and robust. Both aesthetic and static qualities are improved with respect to grid shell competitors.

ACS Style

Francesco Laccone; Luigi Malomo; Maurizio Froli; Paolo Cignoni; Nico Pietroni. Automatic Design of Cable‐Tensioned Glass Shells. Computer Graphics Forum 2019, 39, 260 -273.

AMA Style

Francesco Laccone, Luigi Malomo, Maurizio Froli, Paolo Cignoni, Nico Pietroni. Automatic Design of Cable‐Tensioned Glass Shells. Computer Graphics Forum. 2019; 39 (1):260-273.

Chicago/Turabian Style

Francesco Laccone; Luigi Malomo; Maurizio Froli; Paolo Cignoni; Nico Pietroni. 2019. "Automatic Design of Cable‐Tensioned Glass Shells." Computer Graphics Forum 39, no. 1: 260-273.

Journal article
Published: 30 May 2019 in Signal Processing: Image Communication
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We present a method for turning a flash selfie taken with a smartphone into a photograph as if it was taken in a studio setting with uniform lighting. Our method uses a convolutional neural network trained on a set of pairs of photographs acquired in an ad-hoc acquisition campaign. Each pair consists of one photograph of a subject’s face taken with the camera flash enabled and another one of the same subject in the same pose illuminated using a photographic studio-lighting setup. We show how our method can amend defects introduced by a close-up camera flash, such as specular highlights, shadows, skin shine, and flattened images.

ACS Style

Nicola Capece; Francesco Banterle; Paolo Cignoni; Fabio Ganovelli; Roberto Scopigno; Ugo Erra. DeepFlash: Turning a flash selfie into a studio portrait. Signal Processing: Image Communication 2019, 77, 28 -39.

AMA Style

Nicola Capece, Francesco Banterle, Paolo Cignoni, Fabio Ganovelli, Roberto Scopigno, Ugo Erra. DeepFlash: Turning a flash selfie into a studio portrait. Signal Processing: Image Communication. 2019; 77 ():28-39.

Chicago/Turabian Style

Nicola Capece; Francesco Banterle; Paolo Cignoni; Fabio Ganovelli; Roberto Scopigno; Ugo Erra. 2019. "DeepFlash: Turning a flash selfie into a studio portrait." Signal Processing: Image Communication 77, no. : 28-39.

Journal article
Published: 01 May 2019 in Computer-Aided Design
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ACS Style

Matteo Bracci; Marco Tarini; Nico Pietroni; Marco Livesu; Paolo Cignoni. HexaLab.net: An online viewer for hexahedral meshes. Computer-Aided Design 2019, 110, 24 -36.

AMA Style

Matteo Bracci, Marco Tarini, Nico Pietroni, Marco Livesu, Paolo Cignoni. HexaLab.net: An online viewer for hexahedral meshes. Computer-Aided Design. 2019; 110 ():24-36.

Chicago/Turabian Style

Matteo Bracci; Marco Tarini; Nico Pietroni; Marco Livesu; Paolo Cignoni. 2019. "HexaLab.net: An online viewer for hexahedral meshes." Computer-Aided Design 110, no. : 24-36.

Journal article
Published: 10 January 2019 in ACM Transactions on Graphics
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ACS Style

Luigi Malomo; Jesús Pérez; Emmanuel Iarussi; Nico Pietroni; Eder Miguel; Paolo Cignoni; Bernd Bickel. FlexMaps. ACM Transactions on Graphics 2019, 37, 1 -14.

AMA Style

Luigi Malomo, Jesús Pérez, Emmanuel Iarussi, Nico Pietroni, Eder Miguel, Paolo Cignoni, Bernd Bickel. FlexMaps. ACM Transactions on Graphics. 2019; 37 (6):1-14.

Chicago/Turabian Style

Luigi Malomo; Jesús Pérez; Emmanuel Iarussi; Nico Pietroni; Eder Miguel; Paolo Cignoni; Bernd Bickel. 2019. "FlexMaps." ACM Transactions on Graphics 37, no. 6: 1-14.

Journal article
Published: 10 August 2018 in ACM Transactions on Graphics
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ACS Style

Thomas Alderighi; Luigi Malomo; Daniela Giorgi; Nico Pietroni; Bernd Bickel; Paolo Cignoni. Metamolds. ACM Transactions on Graphics 2018, 37, 1 -13.

AMA Style

Thomas Alderighi, Luigi Malomo, Daniela Giorgi, Nico Pietroni, Bernd Bickel, Paolo Cignoni. Metamolds. ACM Transactions on Graphics. 2018; 37 (4):1-13.

Chicago/Turabian Style

Thomas Alderighi; Luigi Malomo; Daniela Giorgi; Nico Pietroni; Bernd Bickel; Paolo Cignoni. 2018. "Metamolds." ACM Transactions on Graphics 37, no. 4: 1-13.

Journal article
Published: 01 August 2018 in ISPRS Journal of Photogrammetry and Remote Sensing
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ACS Style

Gianpaolo Palma; Tamy Boubekeur; Fabio Ganovelli; Paolo Cignoni. Scalable non-rigid registration for multi-view stereo data. ISPRS Journal of Photogrammetry and Remote Sensing 2018, 142, 328 -341.

AMA Style

Gianpaolo Palma, Tamy Boubekeur, Fabio Ganovelli, Paolo Cignoni. Scalable non-rigid registration for multi-view stereo data. ISPRS Journal of Photogrammetry and Remote Sensing. 2018; 142 ():328-341.

Chicago/Turabian Style

Gianpaolo Palma; Tamy Boubekeur; Fabio Ganovelli; Paolo Cignoni. 2018. "Scalable non-rigid registration for multi-view stereo data." ISPRS Journal of Photogrammetry and Remote Sensing 142, no. : 328-341.

Journal article
Published: 21 February 2018 in Computer Graphics Forum
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Digital fabrication devices are powerful tools for creating tangible reproductions of 3D digital models. Most available printing technologies aim at producing an accurate copy of a tridimensional shape. However, fabrication technologies can also be used to create a stylistic representation of a digital shape. We refer to this class of methods as ‘stylized fabrication methods’. These methods abstract geometric and physical features of a given shape to create an unconventional representation, to produce an optical illusion or to devise a particular interaction with the fabricated model. In this state-of-the-art report, we classify and overview this broad and emerging class of approaches and also propose possible directions for future research.

ACS Style

Bernd Bickel; Paolo Cignoni; Luigi Malomo; Nico Pietroni. State of the Art on Stylized Fabrication. Computer Graphics Forum 2018, 37, 325 -342.

AMA Style

Bernd Bickel, Paolo Cignoni, Luigi Malomo, Nico Pietroni. State of the Art on Stylized Fabrication. Computer Graphics Forum. 2018; 37 (6):325-342.

Chicago/Turabian Style

Bernd Bickel; Paolo Cignoni; Luigi Malomo; Nico Pietroni. 2018. "State of the Art on Stylized Fabrication." Computer Graphics Forum 37, no. 6: 325-342.

Website
Published: 19 December 2017 in Digital Imaging for Cultural Heritage Preservation
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ACS Style

Marco Callieri; Matteo Dellepiane; Paolo Cignoni; Roberto Scopigno. Processing Sampled 3D Data: Reconstruction and Visualization Technologies. Digital Imaging for Cultural Heritage Preservation 2017, 69 -99.

AMA Style

Marco Callieri, Matteo Dellepiane, Paolo Cignoni, Roberto Scopigno. Processing Sampled 3D Data: Reconstruction and Visualization Technologies. Digital Imaging for Cultural Heritage Preservation. 2017; ():69-99.

Chicago/Turabian Style

Marco Callieri; Matteo Dellepiane; Paolo Cignoni; Roberto Scopigno. 2017. "Processing Sampled 3D Data: Reconstruction and Visualization Technologies." Digital Imaging for Cultural Heritage Preservation , no. : 69-99.

Journal article
Published: 20 November 2017 in ACM Transactions on Graphics
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We propose a novel framework for the computational design of tensegrity structures, which are constructions made of struts and cables, held rigid by continuous tension between the elements. Tensegrities are known to be difficult to design---existing design methods are often restricted to using symmetric or templated configurations, limiting the design space to simple constructions. We introduce an algorithm to automatically create free-form stable tensegrity designs that satisfy both fabrication and geometric constraints, and faithfully approximate input geometric shapes. Our approach sidesteps the usual force-based approach in favor of a geometric optimization on the positions of the elements. Equipped with this formulation, we provide a design framework to explore the highly constrained space of tensegrity structures. We validate our method with simulations and real-world constructions.

ACS Style

Nico Pietroni; Marco Tarini; Amir Vaxman; Daniele Panozzo; Paolo Cignoni. Position-based tensegrity design. ACM Transactions on Graphics 2017, 36, 1 -14.

AMA Style

Nico Pietroni, Marco Tarini, Amir Vaxman, Daniele Panozzo, Paolo Cignoni. Position-based tensegrity design. ACM Transactions on Graphics. 2017; 36 (6):1-14.

Chicago/Turabian Style

Nico Pietroni; Marco Tarini; Amir Vaxman; Daniele Panozzo; Paolo Cignoni. 2017. "Position-based tensegrity design." ACM Transactions on Graphics 36, no. 6: 1-14.

Journal article
Published: 28 June 2017 in Computer Graphics Forum
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The wide availability of 3D acquisition devices makes viable their use for shape monitoring. The current techniques for the analysis of time-varying data can efficiently detect actual significant geometric changes and rule out differences due to irrelevant variations (such as sampling, lighting and coverage). On the other hand, the effective visualization of such detected changes can be challenging when we want to show at the same time the original appearance of the 3D model. In this paper, we propose a dynamic technique for the effective visualization of detected differences between two 3D scenes. The presented approach, while retaining the original appearance, allows the user to switch between the two models in a way that enhances the geometric differences that have been detected as significant. Additionally, the same technique is able to visually hides the other negligible, yet visible, variations. The main idea is to use two distinct screen space time-based interpolation functions for the significant 3D differences and for the small variations to hide. We have validated the proposed approach in a user study on a different class of datasets, proving the objective and subjective effectiveness of the method.

ACS Style

Gianpaolo Palma; Manuele Sabbadin; Massimiliano Corsini; Paolo Cignoni. Enhanced Visualization of Detected 3D Geometric Differences. Computer Graphics Forum 2017, 37, 159 -171.

AMA Style

Gianpaolo Palma, Manuele Sabbadin, Massimiliano Corsini, Paolo Cignoni. Enhanced Visualization of Detected 3D Geometric Differences. Computer Graphics Forum. 2017; 37 (1):159-171.

Chicago/Turabian Style

Gianpaolo Palma; Manuele Sabbadin; Massimiliano Corsini; Paolo Cignoni. 2017. "Enhanced Visualization of Detected 3D Geometric Differences." Computer Graphics Forum 37, no. 1: 159-171.

Journal article
Published: 11 November 2016 in ACM Transactions on Graphics
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We present FlexMolds, a novel computational approach to automatically design flexible, reusable molds that, once 3D printed, allow us to physically fabricate, by means of liquid casting, multiple copies of complex shapes with rich surface details and complex topology. The approach to design such flexible molds is based on a greedy bottom-up search of possible cuts over an object, evaluating for each possible cut the feasibility of the resulting mold. We use a dynamic simulation approach to evaluate candidate molds, providing a heuristic to generate forces that are able to open, detach, and remove a complex mold from the object it surrounds. We have tested the approach with a number of objects with nontrivial shapes and topologies.

ACS Style

Luigi Malomo; Nico Pietroni; Bernd Bickel; Paolo Cignoni. FlexMolds. ACM Transactions on Graphics 2016, 35, 1 -12.

AMA Style

Luigi Malomo, Nico Pietroni, Bernd Bickel, Paolo Cignoni. FlexMolds. ACM Transactions on Graphics. 2016; 35 (6):1-12.

Chicago/Turabian Style

Luigi Malomo; Nico Pietroni; Bernd Bickel; Paolo Cignoni. 2016. "FlexMolds." ACM Transactions on Graphics 35, no. 6: 1-12.

Journal article
Published: 27 October 2016 in Computer Graphics Forum
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Given a cross field over a triangulated surface we present a practical and robust method to compute a field aligned coarse quad layout over the surface. The method works directly on a triangle mesh without requiring any parametrization and it is based on a new technique for tracing field-coherent geodesic paths directly on a triangle mesh, and on a new relaxed formulation of a binary LP problem, which allows us to extract both conforming quad layouts and coarser layouts containing t-junctions. Our method is easy to implement, very robust, and, being directly based on the input cross field, it is able to generate better aligned layouts, even with complicated fields containing many singularities. We show results on a number of datasets and comparisons with state-of-the-art methods.

ACS Style

Nico Pietroni; Enrico Puppo; Giorgio Marcias; Roberto Scopigno; Paolo Cignoni. Tracing Field-Coherent Quad Layouts. Computer Graphics Forum 2016, 35, 485 -496.

AMA Style

Nico Pietroni, Enrico Puppo, Giorgio Marcias, Roberto Scopigno, Paolo Cignoni. Tracing Field-Coherent Quad Layouts. Computer Graphics Forum. 2016; 35 (7):485-496.

Chicago/Turabian Style

Nico Pietroni; Enrico Puppo; Giorgio Marcias; Roberto Scopigno; Paolo Cignoni. 2016. "Tracing Field-Coherent Quad Layouts." Computer Graphics Forum 35, no. 7: 485-496.