2020
Journal article
Open Access
A bending-active twisted-arch plywood structure: computational design and fabrication of the FlexMaps Pavilion
Laccone F., Malomo L., Pérez J., Pietroni N., Ponchio F., Bickel B., Cignoni P.
Bending-active structures are able to efficiently produce complex curved shapes from flat panels. The desired deformation of the panels derives from the proper selection of their elastic properties. Optimized panels, called FlexMaps, are designed such that, once they are bent and assembled, the resulting static equilibrium configuration matches a desired input 3D shape. The FlexMaps elastic properties are controlled by locally varying spiraling geometric mesostructures, which are optimized in size and shape to match specific bending requests, namely the global curvature of the target shape. The design pipeline starts from a quad mesh representing the input 3D shape, which defines the edge size and the total amount of spirals: every quad will embed one spiral. Then, an optimization algorithm tunes the geometry of the spirals by using a simplified pre-computed rod model. This rod model is derived from a non-linear regression algorithm which approximates the non-linear behavior of solid FEM spiral models subject to hundreds of load combinations. This innovative pipeline has been applied to the project of a lightweight plywood pavilion named FlexMaps Pavilion, which is a single-layer piecewise twisted arch that fits a bounding box of 3.90x3.96x3.25 meters. This case study serves to test the applicability of this methodology at the architectural scale. The structure is validated via FE analyses and the fabrication of the full scale prototype.Source: SN Applied Sciences 2 (2020). doi:10.1007/s42452-020-03305-w
DOI: 10.1007/s42452-020-03305-w
Project(s): EVOCATION
Metrics:
Laccone F., Malomo L., Pérez J., Pietroni N., Ponchio F., Bickel B., Cignoni P.
Bending-active structures are able to efficiently produce complex curved shapes from flat panels. The desired deformation of the panels derives from the proper selection of their elastic properties. Optimized panels, called FlexMaps, are designed such that, once they are bent and assembled, the resulting static equilibrium configuration matches a desired input 3D shape. The FlexMaps elastic properties are controlled by locally varying spiraling geometric mesostructures, which are optimized in size and shape to match specific bending requests, namely the global curvature of the target shape. The design pipeline starts from a quad mesh representing the input 3D shape, which defines the edge size and the total amount of spirals: every quad will embed one spiral. Then, an optimization algorithm tunes the geometry of the spirals by using a simplified pre-computed rod model. This rod model is derived from a non-linear regression algorithm which approximates the non-linear behavior of solid FEM spiral models subject to hundreds of load combinations. This innovative pipeline has been applied to the project of a lightweight plywood pavilion named FlexMaps Pavilion, which is a single-layer piecewise twisted arch that fits a bounding box of 3.90x3.96x3.25 meters. This case study serves to test the applicability of this methodology at the architectural scale. The structure is validated via FE analyses and the fabrication of the full scale prototype.Source: SN Applied Sciences 2 (2020). doi:10.1007/s42452-020-03305-w
DOI: 10.1007/s42452-020-03305-w
Project(s): EVOCATION
Metrics:
See at:
SN Applied Sciences 
| link.springer.com | SN Applied Sciences | ISTI Repository | CNR ExploRA
2019
Journal article
Open Access
Automatic design of cable-tensioned glass shells
Laccone F., Malomo L., Froli M., Cignoni P., Pietroni N.
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.Source: Computer graphics forum (Online) 39 (2019): 260–273. doi:10.1111/cgf.13801
DOI: 10.1111/cgf.13801
Metrics:
Laccone F., Malomo L., Froli M., Cignoni P., Pietroni N.
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.Source: Computer graphics forum (Online) 39 (2019): 260–273. doi:10.1111/cgf.13801
DOI: 10.1111/cgf.13801
Metrics:
See at:
ISTI Repository | Computer Graphics Forum 
| onlinelibrary.wiley.com | CNR ExploRA
2019
Journal article
Open Access
Volume-aware design of composite molds
Alderighi T., Malomo L., Giorgi D., Bickel B., Cignoni P. Pietroni N.
We propose a novel technique for the automatic design of molds to cast highly complex shapes. The technique generates composite, two-piece molds. Each mold piece is made up of a hard plastic shell and a flexible silicone part. Thanks to the thin, soft, and smartly shaped silicone part, which is kept in place by a hard plastic shell, we can cast objects of unprecedented complexity. An innovative algorithm based on a volumetric analysis defines the layout of the internal cuts in the silicone mold part. Our approach can robustly handle thin protruding features and intertwined topologies that have caused previous methods to fail. We compare our results with state of the art techniques, and we demonstrate the casting of shapes with extremely complex geometry.Source: ACM transactions on graphics 38 (2019). doi:10.1145/3306346.3322981
DOI: 10.1145/3306346.3322981
Project(s): EVOCATION, EMOTIVE , MATERIALIZABLE
Metrics:
Alderighi T., Malomo L., Giorgi D., Bickel B., Cignoni P. Pietroni N.
We propose a novel technique for the automatic design of molds to cast highly complex shapes. The technique generates composite, two-piece molds. Each mold piece is made up of a hard plastic shell and a flexible silicone part. Thanks to the thin, soft, and smartly shaped silicone part, which is kept in place by a hard plastic shell, we can cast objects of unprecedented complexity. An innovative algorithm based on a volumetric analysis defines the layout of the internal cuts in the silicone mold part. Our approach can robustly handle thin protruding features and intertwined topologies that have caused previous methods to fail. We compare our results with state of the art techniques, and we demonstrate the casting of shapes with extremely complex geometry.Source: ACM transactions on graphics 38 (2019). doi:10.1145/3306346.3322981
DOI: 10.1145/3306346.3322981
Project(s): EVOCATION
, EMOTIVE , MATERIALIZABLE Metrics:
See at:
ISTI Repository | ACM Transactions on Graphics | dl.acm.org | ACM Transactions on Graphics | CNR ExploRA
2019
Conference article
Open Access
FlexMaps Pavilion: a twisted arc made of mesostructured flat flexible panels
Laccone F., Malomo L., Perez J., Pietroni N., Ponchio F., Bickel B., Cignoni P.
Bending-active structures are able to eciently produce complex curved shapes starting from flat panels. The desired deformation of the panels derives from the proper selection of their elastic properties. Optimized panels, called FlexMaps, are designed such that, once they are bent and assembled, the resulting static equilibrium conguration matches a desired input 3D shape. The FlexMaps elastic properties are controlled by locally varying spiraling geometric mesostructures, which are optimized in size and shape to match the global curvature (i.e., bending requests) of the target shape. The design pipeline starts from a quad mesh representing the input 3D shape, which denes the edge size and the total amount of spirals: every quad will embed one spiral. Then, an optimization algorithm tunes the geometry of the spirals by using a simplied pre-computed rod model. This rod model is derived from a non-linear regression algorithm which approximates the non-linear behavior of solid FEM spiral models subject to hundreds of load combinations. This innovative pipeline has been applied to the project of a lightweight plywood pavilion named FlexMaps Pavilion, which is a single-layer piecewise twisted arc that ts a bounding box of 3.90x3.96x3.25 meters.Source: FORM and FORCE, IASS Symposium 2019 60th Anniversary Symposium of the International Association for Shell and Spatial Structures Structural Membranes 2019 9th International Conference on Textile Composites and Inflatable Structures, pp. 498–504, Barcelona, 7-10/10/2019
Laccone F., Malomo L., Perez J., Pietroni N., Ponchio F., Bickel B., Cignoni P.
Bending-active structures are able to eciently produce complex curved shapes starting from flat panels. The desired deformation of the panels derives from the proper selection of their elastic properties. Optimized panels, called FlexMaps, are designed such that, once they are bent and assembled, the resulting static equilibrium conguration matches a desired input 3D shape. The FlexMaps elastic properties are controlled by locally varying spiraling geometric mesostructures, which are optimized in size and shape to match the global curvature (i.e., bending requests) of the target shape. The design pipeline starts from a quad mesh representing the input 3D shape, which denes the edge size and the total amount of spirals: every quad will embed one spiral. Then, an optimization algorithm tunes the geometry of the spirals by using a simplied pre-computed rod model. This rod model is derived from a non-linear regression algorithm which approximates the non-linear behavior of solid FEM spiral models subject to hundreds of load combinations. This innovative pipeline has been applied to the project of a lightweight plywood pavilion named FlexMaps Pavilion, which is a single-layer piecewise twisted arc that ts a bounding box of 3.90x3.96x3.25 meters.Source: FORM and FORCE, IASS Symposium 2019 60th Anniversary Symposium of the International Association for Shell and Spatial Structures Structural Membranes 2019 9th International Conference on Textile Composites and Inflatable Structures, pp. 498–504, Barcelona, 7-10/10/2019
See at:
ISTI Repository | CNR ExploRA
2019
Conference article
Open Access
Concept and cable-tensioning optimization of post-tensioned shells made of structural glass
Laccone F., Malomo L., Froli M., Cignoni P., Pietroni N.
Shells made of structural glass are charming objects from both the aesthetics and the engineering point of view. However, they pose two signicant challenges: the rst one is to assure adequate safety and redundancy concerning possible global collapse; the second one is to guarantee the economy for replacing collapsed components. To address both requirements, this research explores a novel concept where triangular panels of structural glass are both post-tensioned and reinforced to create 3D free-form systems. Hence, the ligree steel truss, made of edges reinforcements, is sized in performance-based perspective to bear at least the weight of all panels in the occurrence of simultaneous cracks (worst-case scenario). The panels are post-tensioned using a set of edge-aligned cables that add benecial compressive stress on the surface. The cable placement and pre-loads are optimized to minimize the tensile stress acting on the shell and match the manufacturing constraints. These shells optimize material usage by providing not only a transparent and fascinating building separation but also load-bearing capabilities. Visual and structural lightness are improved to grid shell competitors.Source: FORM and FORCE, IASS Symposium 2019 60th Anniversary Symposium of the International Association for Shell and Spatial Structures Structural Membranes 2019 9th International Conference on Textile Composites and Inflatable Structures, pp. 2133–2140, Barcelona, 7-10/10/2019
Laccone F., Malomo L., Froli M., Cignoni P., Pietroni N.
Shells made of structural glass are charming objects from both the aesthetics and the engineering point of view. However, they pose two signicant challenges: the rst one is to assure adequate safety and redundancy concerning possible global collapse; the second one is to guarantee the economy for replacing collapsed components. To address both requirements, this research explores a novel concept where triangular panels of structural glass are both post-tensioned and reinforced to create 3D free-form systems. Hence, the ligree steel truss, made of edges reinforcements, is sized in performance-based perspective to bear at least the weight of all panels in the occurrence of simultaneous cracks (worst-case scenario). The panels are post-tensioned using a set of edge-aligned cables that add benecial compressive stress on the surface. The cable placement and pre-loads are optimized to minimize the tensile stress acting on the shell and match the manufacturing constraints. These shells optimize material usage by providing not only a transparent and fascinating building separation but also load-bearing capabilities. Visual and structural lightness are improved to grid shell competitors.Source: FORM and FORCE, IASS Symposium 2019 60th Anniversary Symposium of the International Association for Shell and Spatial Structures Structural Membranes 2019 9th International Conference on Textile Composites and Inflatable Structures, pp. 2133–2140, Barcelona, 7-10/10/2019
See at:
ISTI Repository | CNR ExploRA
2019
Journal article
Open Access
QuadMixer: layout preserving blending of quadrilateral meshes
Nuvoli S., Hernandez A., Esperança C., Scateni R., Cignoni P., Pietroni N.
We propose QuadMixer, a novel interactive technique to compose quad mesh components preserving the majority of the original layouts. Quad Layout is a crucial property for many applications since it conveys important information that would otherwise be destroyed by techniques that aim only at preserving shape. Our technique keeps untouched all the quads in the patches which are not involved in the blending. We first perform robust boolean operations on the corresponding triangle meshes. Then we use this result to identify and build new surface patches for small regions neighboring the intersection curves. These blending patches are carefully quadrangulated respecting boundary constraints and stitched back to the untouched parts of the original models. The resulting mesh preserves the designed edge flow that, by construction, is captured and incorporated to the new quads as much as possible. We present our technique in an interactive tool to show its usability and robustness.Source: ACM transactions on graphics 38 (2019): 180:1–180:13. doi:10.1145/3355089.3356542
DOI: 10.1145/3355089.3356542
Metrics:
Nuvoli S., Hernandez A., Esperança C., Scateni R., Cignoni P., Pietroni N.
We propose QuadMixer, a novel interactive technique to compose quad mesh components preserving the majority of the original layouts. Quad Layout is a crucial property for many applications since it conveys important information that would otherwise be destroyed by techniques that aim only at preserving shape. Our technique keeps untouched all the quads in the patches which are not involved in the blending. We first perform robust boolean operations on the corresponding triangle meshes. Then we use this result to identify and build new surface patches for small regions neighboring the intersection curves. These blending patches are carefully quadrangulated respecting boundary constraints and stitched back to the untouched parts of the original models. The resulting mesh preserves the designed edge flow that, by construction, is captured and incorporated to the new quads as much as possible. We present our technique in an interactive tool to show its usability and robustness.Source: ACM transactions on graphics 38 (2019): 180:1–180:13. doi:10.1145/3355089.3356542
DOI: 10.1145/3355089.3356542
Metrics:
See at:
ISTI Repository | ACM Transactions on Graphics | doi.acm.org | ACM Transactions on Graphics | CNR ExploRA
2018
Journal article
Open Access
State of the art on stylized fabrication
Bickel B., Cignoni P., Malomo L., Pietroni N.
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.Source: Computer graphics forum (Print) 37 (2018): 325–342. doi:10.1111/cgf.13327
DOI: 10.1111/cgf.13327
Project(s): EMOTIVE, MATERIALIZABLE
Metrics:
Bickel B., Cignoni P., Malomo L., Pietroni N.
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.Source: Computer graphics forum (Print) 37 (2018): 325–342. doi:10.1111/cgf.13327
DOI: 10.1111/cgf.13327
Project(s): EMOTIVE
, MATERIALIZABLE Metrics:
See at:
ISTI Repository | Computer Graphics Forum | Computer Graphics Forum | onlinelibrary.wiley.com | CNR ExploRA
2018
Report
Unknown
Metamolds: Computational design of silicone molds
Alderighi T., Malomo L., Giorgi D., Pietroni N., Bickel B., Cignoni P.
We propose a new method for fabricating digital objects through reusable silicone molds. Molds are generated by casting liquid silicone into custom 3D printed containers called metamolds. Metamolds automatically define the cuts that are needed to extract the cast object from the silicone mold. The shape of metamolds is designed through a novel segmentation technique, which takes into account both geometric and topological constraints involved in the process of mold casting. Our technique is simple, does not require to change the shape or topology of the input objects, and only requires off-the-shelf materials and technologies. We successfully tested our method on a set of challenging examples with complex shapes and rich geometric detail.Source: ISTI Technical reports, 2018
Project(s): EMOTIVE
Alderighi T., Malomo L., Giorgi D., Pietroni N., Bickel B., Cignoni P.
We propose a new method for fabricating digital objects through reusable silicone molds. Molds are generated by casting liquid silicone into custom 3D printed containers called metamolds. Metamolds automatically define the cuts that are needed to extract the cast object from the silicone mold. The shape of metamolds is designed through a novel segmentation technique, which takes into account both geometric and topological constraints involved in the process of mold casting. Our technique is simple, does not require to change the shape or topology of the input objects, and only requires off-the-shelf materials and technologies. We successfully tested our method on a set of challenging examples with complex shapes and rich geometric detail.Source: ISTI Technical reports, 2018
Project(s): EMOTIVE
See at: CNR ExploRA
2018
Journal article
Open Access
Metamolds: computational design of silicone molds
Alderighi T., Malomo L., Giorgi D., Pietroni N., Bickel B., Cignoni P.
We propose a new method for fabricating digital objects through reusable silicone molds. Molds are generated by casting liquid silicone into custom 3D printed containers called metamolds. Metamolds automatically define the cuts that are needed to extract the cast object from the silicone mold. The shape of metamolds is designed through a novel segmentation technique, which takes into account both geometric and topological constraints involved in the process of mold casting. Our technique is simple, does not require changing the shape or topology of the input objects, and only requires off-the-shelf materials and technologies. We successfully tested our method on a set of challenging examples with complex shapes and rich geometric detailSource: ACM transactions on graphics 37 (2018): 136:1–136:13. doi:10.1145/3197517.3201381
DOI: 10.1145/3197517.3201381
Project(s): EMOTIVE
Metrics:
Alderighi T., Malomo L., Giorgi D., Pietroni N., Bickel B., Cignoni P.
We propose a new method for fabricating digital objects through reusable silicone molds. Molds are generated by casting liquid silicone into custom 3D printed containers called metamolds. Metamolds automatically define the cuts that are needed to extract the cast object from the silicone mold. The shape of metamolds is designed through a novel segmentation technique, which takes into account both geometric and topological constraints involved in the process of mold casting. Our technique is simple, does not require changing the shape or topology of the input objects, and only requires off-the-shelf materials and technologies. We successfully tested our method on a set of challenging examples with complex shapes and rich geometric detailSource: ACM transactions on graphics 37 (2018): 136:1–136:13. doi:10.1145/3197517.3201381
DOI: 10.1145/3197517.3201381
Project(s): EMOTIVE
Metrics:
See at:
ISTI Repository | IST PubRep | dl.acm.org | ACM Transactions on Graphics | CNR ExploRA
2018
Journal article
Open Access
FlexMaps: computational design of flat flexible shells for shaping 3D objects
Malomo L., Pérez J., Iarussi E., Pietroni N., Miguel E., Cignoni P., Bickel B.
We propose FlexMaps, a novel framework for fabricating smooth shapes out of flat, flexible panels with tailored mechanical properties. We start by mapping the 3D surface onto a 2D domain as in traditional UV mapping to design a set of deformable flat panels called FlexMaps. For these panels, we design and obtain specific mechanical properties such that, once they are assembled, the static equilibrium configuration matches the desired 3D shape. FlexMaps can be fabricated from an almost rigid material, such as wood or plastic, and are made flexible in a controlled way by using computationally designed spiraling microstructures.Source: ACM transactions on graphics 37 (2018). doi:10.1145/3272127.3275076
DOI: 10.1145/3272127.3275076
Project(s): EMOTIVE, MATERIALIZABLE , SoMa
Metrics:
Malomo L., Pérez J., Iarussi E., Pietroni N., Miguel E., Cignoni P., Bickel B.
We propose FlexMaps, a novel framework for fabricating smooth shapes out of flat, flexible panels with tailored mechanical properties. We start by mapping the 3D surface onto a 2D domain as in traditional UV mapping to design a set of deformable flat panels called FlexMaps. For these panels, we design and obtain specific mechanical properties such that, once they are assembled, the static equilibrium configuration matches the desired 3D shape. FlexMaps can be fabricated from an almost rigid material, such as wood or plastic, and are made flexible in a controlled way by using computationally designed spiraling microstructures.Source: ACM transactions on graphics 37 (2018). doi:10.1145/3272127.3275076
DOI: 10.1145/3272127.3275076
Project(s): EMOTIVE
, MATERIALIZABLE , SoMa Metrics:
See at:
ISTI Repository | IST PubRep | dl.acm.org | ACM Transactions on Graphics | CNR ExploRA
2017
Journal article
Open Access
Digital Fabrication Techniques for Cultural Heritage: A Survey
Scopigno R., Cignoni P., Pietroni N., Callieri M., Dellepiane M.
Digital fabrication devices exploit basic technologies in order to create tangible reproductions of 3D digital models. Although current 3D printing pipelines still suffer from several restrictions, accuracy in reproduction has reached an excellent level. The manufacturing industry has been the main domain of 3D printing applications over the last decade. Digital fabrication techniques have also been demonstrated to be effective in many other contexts, including the consumer domain. The Cultural Heritage is one of the new application contexts and is an ideal domain to test the flexibility and quality of this new technology. This survey overviews the various fabrication technologies, discussing their strengths, limitations and costs. Various successful uses of 3D printing in the Cultural Heritage are analysed, which should also be useful for other application contexts. We review works that have attempted to extend fabrication technologies in order to deal with the specific issues in the use of digital fabrication in the Cultural Heritage. Finally, we also propose areas for future research.Source: Computer graphics forum (Online) 36 (2017): 6–21. doi:10.1111/cgf.12781
DOI: 10.1111/cgf.12781
Metrics:
Scopigno R., Cignoni P., Pietroni N., Callieri M., Dellepiane M.
Digital fabrication devices exploit basic technologies in order to create tangible reproductions of 3D digital models. Although current 3D printing pipelines still suffer from several restrictions, accuracy in reproduction has reached an excellent level. The manufacturing industry has been the main domain of 3D printing applications over the last decade. Digital fabrication techniques have also been demonstrated to be effective in many other contexts, including the consumer domain. The Cultural Heritage is one of the new application contexts and is an ideal domain to test the flexibility and quality of this new technology. This survey overviews the various fabrication technologies, discussing their strengths, limitations and costs. Various successful uses of 3D printing in the Cultural Heritage are analysed, which should also be useful for other application contexts. We review works that have attempted to extend fabrication technologies in order to deal with the specific issues in the use of digital fabrication in the Cultural Heritage. Finally, we also propose areas for future research.Source: Computer graphics forum (Online) 36 (2017): 6–21. doi:10.1111/cgf.12781
DOI: 10.1111/cgf.12781
Metrics:
See at:
ISTI Repository | Computer Graphics Forum | onlinelibrary.wiley.com | CNR ExploRA
2017
Journal article
Open Access
Conception and parametric design workflow for a timber large-spanned reversible grid shell to shelter the archaeological site of the Roman Shipwrecks in Pisa
Corio E., Laccone F., Pietroni N., Cignoni P., Froli M.
Reciprocal structures, or nexorade, are composed by the assembling of groups of three or more beams mutually connected by mono-lateral T joints in a way that any relative movement is suppressed. This kind of structures can be easily built in relatively unprepared sites, dismantled, transported and reused even by not specialized handcraft. For these reasons, reciprocal structures have been widely used in the past for military purposes, and nowadays they seem to satisfy very well the different requirements of a quick and temporary shelter of a large archaeological area when they are shaped as grid shells. This paper proposes the design of a reversible, reciprocal framed grid shell to shelter the archaeological site of the Roman Shipwrecks in Pisa. The structure must protect excavations and archaeologists from the weather and provide an easy access to visitors. Additionally, it must allow for easy disassembling and moving to another site. The design choices aim at optimizing both structural efficiency and esthetical qualities. A parametric workflow for both the form finding and the digital fabrication processes has been developed, and a prototype of accommodative steel T-joint for timber reciprocal beams has been realized. Finally, a model using CNC- cutting tested the structural feasibility of such a design approach.Source: International journal of computational methods and experimental measurements (Print) 5 (2017): 551–561. doi:10.2495/CMEM-V5-N4-551-561
DOI: 10.2495/cmem-v5-n4-551-561
Metrics:
Corio E., Laccone F., Pietroni N., Cignoni P., Froli M.
Reciprocal structures, or nexorade, are composed by the assembling of groups of three or more beams mutually connected by mono-lateral T joints in a way that any relative movement is suppressed. This kind of structures can be easily built in relatively unprepared sites, dismantled, transported and reused even by not specialized handcraft. For these reasons, reciprocal structures have been widely used in the past for military purposes, and nowadays they seem to satisfy very well the different requirements of a quick and temporary shelter of a large archaeological area when they are shaped as grid shells. This paper proposes the design of a reversible, reciprocal framed grid shell to shelter the archaeological site of the Roman Shipwrecks in Pisa. The structure must protect excavations and archaeologists from the weather and provide an easy access to visitors. Additionally, it must allow for easy disassembling and moving to another site. The design choices aim at optimizing both structural efficiency and esthetical qualities. A parametric workflow for both the form finding and the digital fabrication processes has been developed, and a prototype of accommodative steel T-joint for timber reciprocal beams has been realized. Finally, a model using CNC- cutting tested the structural feasibility of such a design approach.Source: International journal of computational methods and experimental measurements (Print) 5 (2017): 551–561. doi:10.2495/CMEM-V5-N4-551-561
DOI: 10.2495/cmem-v5-n4-551-561
Metrics:
See at:
International Journal of Computational Methods and Experimental Measurements | ISTI Repository | www.witpress.com | International Journal of Computational Methods and Experimental Measurements | CNR ExploRA
2017
Journal article
Open Access
Position-based tensegrity design
Pietroni N., Tarini M., Vaxman A., Panozzo D., Cignoni P.
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 di cult to design-existing design methods are often restricted to us- ing symmetric or templated con gurations, limiting the design space to simple constructions. We introduce an algorithm to automatically create free-form stable tensegrity designs that satisfy both fabrication and geo- metric 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 formu- lation, we provide a design framework to explore the highly constrained space of tensegrity structures. We validate our method with simulations and real-world constructions.Source: ACM transactions on graphics 36 (2017). doi:10.1145/3130800.3130809
DOI: 10.1145/3130800.3130809
Metrics:
Pietroni N., Tarini M., Vaxman A., Panozzo D., Cignoni P.
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 di cult to design-existing design methods are often restricted to us- ing symmetric or templated con gurations, limiting the design space to simple constructions. We introduce an algorithm to automatically create free-form stable tensegrity designs that satisfy both fabrication and geo- metric 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 formu- lation, we provide a design framework to explore the highly constrained space of tensegrity structures. We validate our method with simulations and real-world constructions.Source: ACM transactions on graphics 36 (2017). doi:10.1145/3130800.3130809
DOI: 10.1145/3130800.3130809
Metrics:
See at:
Archivio istituzionale della ricerca - Università dell'Insubria | ISTI Repository | dl.acm.org | ACM Transactions on Graphics | NARCIS | CNR ExploRA
2016
Journal article
Open Access
FlexMolds: Automatic Design of Flexible Shells for Molding
Malomo L., Pietroni N., Bickel B., Cignoni P.
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.Source: ACM transactions on graphics 35 (2016). doi:10.1145/2980179.2982397
DOI: 10.1145/2980179.2982397
Project(s): SoMa
Metrics:
Malomo L., Pietroni N., Bickel B., Cignoni P.
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.Source: ACM transactions on graphics 35 (2016). doi:10.1145/2980179.2982397
DOI: 10.1145/2980179.2982397
Project(s): SoMa
Metrics:
See at:
ISTI Repository | IST PubRep | ACM Transactions on Graphics | dl.acm.org | ACM Transactions on Graphics | CNR ExploRA
2016
Journal article
Open Access
Tracing Field-Coherent Quad Layouts
Pietroni N., Puppo E., Marcias G., Scopigno R., Cignoni P.
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.Source: Computer graphics forum (Print) 35 (2016): 485–496. doi:10.1111/cgf.13045
DOI: 10.1111/cgf.13045
Metrics:
Pietroni N., Puppo E., Marcias G., Scopigno R., Cignoni P.
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.Source: Computer graphics forum (Print) 35 (2016): 485–496. doi:10.1111/cgf.13045
DOI: 10.1111/cgf.13045
Metrics:
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ISTI Repository | Computer Graphics Forum | www.scopus.com | CNR ExploRA
2016
Journal article
Open Access
Stability of Statics Aware Voronoi Grid-Shells
Tonelli D., Pietroni N., Puppo E., Froli M., Cignoni P., Amendola G., Scopigno R.
Grid-shells are lightweight structures used to cover long spans with few load-bearing material, as they excel for lightness, elegance and transparency. In this paper we analyze the stability of hex-dominant free-form grid-shells, generated with the Statics Aware Voronoi Remeshing scheme introduced in Pietroni et al. (2015). This is a novel hex-dominant, organic-like and non uniform remeshing pattern that manages to take into account the statics of the underlying surface. We show how this pattern is particularly suitable for free-form grid-shells, providing good performance in terms of both aesthetics and structural behavior. To reach this goal, we select a set of four contemporary architectural surfaces and we establish a systematic comparative analysis between Statics Aware Voronoi Grid-Shells and equivalent state of the art triangular and quadrilateral grid-shells. For each dataset and for each grid-shell topology, imperfection sensitivity analyses are carried out and the worst response diagrams compared. It turns out that, in spite of the intrinsic weakness of the hexagonal topology, free-form Statics Aware Voronoi Grid-Shells are much more effective than their state-of-the-art quadrilateral counterparts.Source: Engineering structures 116 (2016): 70–82. doi:10.1016/j.engstruct.2016.02.049
DOI: 10.1016/j.engstruct.2016.02.049
Metrics:
Tonelli D., Pietroni N., Puppo E., Froli M., Cignoni P., Amendola G., Scopigno R.
Grid-shells are lightweight structures used to cover long spans with few load-bearing material, as they excel for lightness, elegance and transparency. In this paper we analyze the stability of hex-dominant free-form grid-shells, generated with the Statics Aware Voronoi Remeshing scheme introduced in Pietroni et al. (2015). This is a novel hex-dominant, organic-like and non uniform remeshing pattern that manages to take into account the statics of the underlying surface. We show how this pattern is particularly suitable for free-form grid-shells, providing good performance in terms of both aesthetics and structural behavior. To reach this goal, we select a set of four contemporary architectural surfaces and we establish a systematic comparative analysis between Statics Aware Voronoi Grid-Shells and equivalent state of the art triangular and quadrilateral grid-shells. For each dataset and for each grid-shell topology, imperfection sensitivity analyses are carried out and the worst response diagrams compared. It turns out that, in spite of the intrinsic weakness of the hexagonal topology, free-form Statics Aware Voronoi Grid-Shells are much more effective than their state-of-the-art quadrilateral counterparts.Source: Engineering structures 116 (2016): 70–82. doi:10.1016/j.engstruct.2016.02.049
DOI: 10.1016/j.engstruct.2016.02.049
Metrics:
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ISTI Repository | Engineering Structures | www.sciencedirect.com | CNR ExploRA
2016
Conference article
Restricted
State of the art on functional fabrication
Medeiros E Sá A., Rodriguez-Echavarria K., Pietroni N., Cignoni P.
Digital fabrication technologies are becoming of importance to a number of knowledge areas and sectors, including medicine, entertainment, design, engineering, education, arts and architecture, due to their accessibility and versatility. These technolo- gies are changing the design of digital models, materials and manufacturing processes which enable to build previously un- achievable physical objects. Since many constraints imposed on the design of objects have changed significantly, a growing research community is working on graphical tools and techniques to enable the conception, automation, production and usage of innovative and complex designs for fabrication. In the present work, we survey the state of the art of computer graphics contributions to functional fabrication design tools and techniques. By functional fabrication we understand the design and manufacture of physical objects which functionalities exploit the capabilities of digital fabrication technologies. These func- tionalities include improving the mechanics of a workpiece, producing articulated models, capturing aerodynamics, planning deformable workpieces and controlling the object's appearance and acoustics. The resulting design tools are clearly taking advantage of relevant computer graphics techniques. Furthermore, they are extending these techniques to realise new physical forms as well as bringing innovation to feed into the design space.Source: Eurographics Workshop on Graphics for Digital Fabrication, pp. 1–9, Lisbona, Portugal, 8 May 2016
DOI: 10.2312/gdf.20161073
Metrics:
Medeiros E Sá A., Rodriguez-Echavarria K., Pietroni N., Cignoni P.
Digital fabrication technologies are becoming of importance to a number of knowledge areas and sectors, including medicine, entertainment, design, engineering, education, arts and architecture, due to their accessibility and versatility. These technolo- gies are changing the design of digital models, materials and manufacturing processes which enable to build previously un- achievable physical objects. Since many constraints imposed on the design of objects have changed significantly, a growing research community is working on graphical tools and techniques to enable the conception, automation, production and usage of innovative and complex designs for fabrication. In the present work, we survey the state of the art of computer graphics contributions to functional fabrication design tools and techniques. By functional fabrication we understand the design and manufacture of physical objects which functionalities exploit the capabilities of digital fabrication technologies. These func- tionalities include improving the mechanics of a workpiece, producing articulated models, capturing aerodynamics, planning deformable workpieces and controlling the object's appearance and acoustics. The resulting design tools are clearly taking advantage of relevant computer graphics techniques. Furthermore, they are extending these techniques to realise new physical forms as well as bringing innovation to feed into the design space.Source: Eurographics Workshop on Graphics for Digital Fabrication, pp. 1–9, Lisbona, Portugal, 8 May 2016
DOI: 10.2312/gdf.20161073
Metrics:
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diglib.eg.org | CNR ExploRA
2016
Conference article
Restricted
Design and fabrication of grid-shells mockups
Tonelli D., Pietroni N., Cignoni P., Scopigno R.
Statics Aware Voronoi Grid-shells have been recently introduced in the Architectural Geometry field. These are innovative grid- shells endowed with a polygonal topology, whose geometry is structurally optimized by means of a novel algorithm [PTP+15]. Although being structurally effective as proved in [TPP+16] and arguably aesthetically charming, so far these grid-shells have struggled to attract architects' interest. We propose a method to fabricate a mockup of the grid shell by using modern additive 3D printing and laser cutting technologies. We also show how the realised mockup can be used to perform a preliminary validation of the simulated static performances of the grid-shell structure.Source: Smart Tools and Apps for Graphics - Eurographics Italian Chapter Conference, pp. 3–7, Genova, Italy, 3-4 October 2016
DOI: 10.2312/stag.20161360
Metrics:
Tonelli D., Pietroni N., Cignoni P., Scopigno R.
Statics Aware Voronoi Grid-shells have been recently introduced in the Architectural Geometry field. These are innovative grid- shells endowed with a polygonal topology, whose geometry is structurally optimized by means of a novel algorithm [PTP+15]. Although being structurally effective as proved in [TPP+16] and arguably aesthetically charming, so far these grid-shells have struggled to attract architects' interest. We propose a method to fabricate a mockup of the grid shell by using modern additive 3D printing and laser cutting technologies. We also show how the realised mockup can be used to perform a preliminary validation of the simulated static performances of the grid-shell structure.Source: Smart Tools and Apps for Graphics - Eurographics Italian Chapter Conference, pp. 3–7, Genova, Italy, 3-4 October 2016
DOI: 10.2312/stag.20161360
Metrics:
See at:
diglib.eg.org | CNR ExploRA
2016
Patent
Unknown
Method for computationally designing a re-usable flexible mold
Malomo L., Pietroni N., Bickel B., Cignoni P.
Source: EP3301597, Europeo
Malomo L., Pietroni N., Bickel B., Cignoni P.
Source: EP3301597, Europeo
See at: CNR ExploRA
2015
Journal article
Open Access
Mesh joinery: a method for building fabricable structures
Cignoni P., Pietroni N., Malomo L., Scopigno R.
Mesh joinery is an innovative method to produce illustrative shape approximations suitable for fabrication. Mesh joinery is capable of producing complex fabricable structures in an efficient and visually pleasing manner. We represent an input geometry as a set of planar pieces arranged to compose a rigid structure by exploiting an efficient slit mechanism. Since slices are planar, a standard 2D cutting system is sufficient to fabricate them.Source: ERCIM news 101 (2015): 44–45.
Project(s): HARVEST4D
Cignoni P., Pietroni N., Malomo L., Scopigno R.
Mesh joinery is an innovative method to produce illustrative shape approximations suitable for fabrication. Mesh joinery is capable of producing complex fabricable structures in an efficient and visually pleasing manner. We represent an input geometry as a set of planar pieces arranged to compose a rigid structure by exploiting an efficient slit mechanism. Since slices are planar, a standard 2D cutting system is sufficient to fabricate them.Source: ERCIM news 101 (2015): 44–45.
Project(s): HARVEST4D
See at:
ercim-news.ercim.eu | CNR ExploRA