Abstract: Point cloud 3D models are gaining increasing popularity due to the proliferation of scanning systems in various fields, including autonomous vehicles and robotics. When employed for rendering purposes, point clouds are typically depicted with their original colors acquired during the acquisition, often without taking into account the lighting conditions of the scene in which the model is situated. This can result in a lack of realism in numerous contexts, especially when dealing with animated point clouds used in eXtended reality applications, where it is desirable for the model to respond to incoming light and seamlessly blend with the surrounding environment. This paper proposes the application of physically based rendering (PBR), a rendering technique widely used in real-time computer graphics applications, to animated point cloud models for reproducing specular reflections, and achieving a photo-realistic and physically accurate look under any lighting condition. To achieve this, we first explore the extension of commonly used animated point cloud formats to incorporate normal vectors and PBR parameters, like roughness and metalness. Additionally, the encoding of the animated environment maps necessary for the PBR technique is investigated. Then, an animated point cloud model is rendered with a shader implementing the proposed PBR method. Finally, we compare the outcomes of this PBR pipeline with traditional renderings of the same point cloud produced using commonly used shaders, taking into account different lighting conditions and environments. Through these comparisons, we demonstrate how the proposed PBR method enhances the visual integration of the point cloud with its surroundings. Furthermore, it will be shown that using this rendering technique, it is possible to render different materials, by exploiting the features of PBR and the encoding of the surrounding environment.

Keywords: extended reality | point cloud | real-time rendering

Abstract: As the Metaverse gains popularity due to its use in various industries, so does the desire to take advantage of all its potential. While visual and audio technologies already provide access to the Metaverse, there is increasing interest in haptic and olfactory technologies, which are less developed and have been studied for a shorter time. Currently, there are limited options for users to experience the olfactory aspect of the Metaverse. This paper introduces an open-source kit that makes it simple to add the sense of smell to the Metaverse. The solution is modular, allowing for the simultaneous use of multiple odors and compatibility with both desktop and wearable applications. The details of the solution, including its technical specifications, are outlined to enable potential users to utilize, test, and enhance the project and make it available to the scientific community.

Keywords: Metaverse | olfactory display | smell | virtual and augmented reality environments

Abstract: Teaching technical contents related to product design and 3D modeling is a challenging task. Students enrolled in Master of Science courses often have different backgrounds and technical skills, due to their different educational paths at the bachelor’s degree. From the student’s perspective, one of the main difficulties concerns the definition of the 3D modeling procedure, understand technical drawings and figuring out the proper assembly sequence to get the final product. Over the years, some methods to fill these existing gaps have been experimented, such as tutoring and Massive Open Online Courses. Despite these passive approaches have been proven useful for students, digital technologies, such as Virtual Reality, can boost the implementation active learning sessions and hands-on experiences. In this paper, we present a Virtual Reality application for active learning developed to help students in the initial stage of the “Methods and tools for detailed design” course to acquire a set of lacking knowledge, which includes technical terminology related to mechanical parts and components, the ability to decompose mechanical systems into sub-parts, and to create a 3D model using a CAD tool given a 2D engineering drawing. To evaluate the effectiveness of the proposed approach, the application has been tested with a cohort of students with different backgrounds and knowledge about mechanical design and CAD.

Keywords: Active learning | hands-on experience | Virtual learning | Virtual Reality | Virtual Reality for education

Abstract: In an era characterized by the increasing complexity of products and the rapid turnover of the workforce across different companies, there is a growing need to invest significantly in quick and efficient training methods. Concurrently, the advancement of digitalization has rendered certain training practices anchored to paper-based materials obsolete. Numerous companies are directing their investments toward digital training, yet the optimal format to exploit the full advantages of digitalization remains unclear. This study undertakes a comparison of four distinct digital versions of the same training process with the aim of comprehending the tangible benefits. The findings indicate that to fully capitalize on the advantages of digital technology, a complete rethinking of training practices is necessary.

Keywords: virtual and augmented reality environments | virtual prototyping

Abstract: Reduction of aerodynamic drag is a crucial aspect of cycling. Currently, to optimize aerodynamics, athletes rely on wind tunnel tests or CFD simulations. Despite the undeniable advantage of the latter in terms of cost and time effort, they still require validation through wind tunnel measurements. This paper introduces a novel workflow that aims to streamline and accelerate the aerodynamic analysis process for cycling. The proposed workflow focuses on utilizing a full-sized mannequin and integrates CFD simulations, wind tunnel validation, 3D scanning, and rigging animation techniques. The animation technique involves the creation of a virtual skeleton that allows the scanned model to be posed in any desired position, eliminating the need for physical adjustments and repetitive wind tunnel testing. To showcase the time-saving advantages of this approach, a steady CFD analysis is conducted to compare six different configurations obtained using the rigged model, in terms of drag areas, velocity streamlines, and pressure coefficient distribution. The obtained data trends closely align with previous similar studies in the literature and the results from the simulation have been compared with wind tunnel test measurements. Additionally, future adjustments to the position or equipment can be easily made using the virtual rigging model. By integrating virtual techniques with CFD simulations and wind tunnel validation, the proposed workflow enables rapid evaluation of aerodynamic performance in a more efficient and cost-effective manner.

Keywords: CFD | Cyclist | Rigging Animation

Abstract: Olfactory Displays are devices used to generate and deliver scented air that is eventually smelled by the users. As the literature reports, their development and evaluation mostly rely on experimental activities based on a “trial-and-error” approach, which prevents a comparative analysis of designed solutions and their technical performances, thus leading to prototypes with low potential to become future products. In this paper, an innovative framework embedding Computational Fluid Dynamics (CFD) simulations for designing, prototyping and testing new Olfactory Displays is proposed. After presenting the framework, the paper illustrates the settings for a multi-phase CFD analysis based on Discrete Particles Modeling for simulating olfactory displays. The design of a new wearable olfactory display is presented, detailing all the steps of the framework. A first architecture is devised, and an initial set of simplified 2D multi-phase CFD simulations has been used to propose possible improvements. A new design has been developed, and a 3D CFD simulation has been run to predict its performance. A set of experiments has been conducted to test the real prototypes and compare the performance with the one predicted by the simulations. The experimental results are in good accordance with the simulations, which have proven their effectiveness in improving the design of the olfactory displays.

Keywords: CFD | Olfactory Display DOI: https://doi.org/ | Rapid Prototyping | Virtual and Physical Prototyping

Abstract: Multi-Material Additive Manufacturing technologies enable the fabrication of objects consisting of multiple materials. Among them, Material Jetting allows the designer to control the spatial distribution of the selected materials down to the size of microns, making it suitable for Functionally Graded Materials. Despite this great capability, governing the design complexity unleashed by this class of material is still limited to the current computer-aided tools. The paper aims at investigating how a traditional Boundary representation (B-rep) in the CAD domain, which has been conceived for homogeneous materials, can be adapted to integrate heterogeneous object specifications. A workflow to produce heterogeneous objects, with a focus on Functionally Graded Material Objects, is outlined, from the design of the object geometry with a CAD system to the generation of the machine instructions. The procedure to specify the desired material distribution and to generate the voxels has been embedded in a traditional CAD software, allowing the users to define the specifications of the heterogeneous object interacting with the B-rep entities. Once the material distribution has been defined, a solid voxelization is performed on the geometry and the material composition for each voxel is computed. Finally, the object is sliced and a set of images is generated, informing the printer which material should be deposited at the specific position. A case study to check the feasibility of the proposed workflow has been performed: different specimens varying the voxel size and the deposition pattern have been printed.

Keywords: Additive manufacturing | Heterogeneous objects | Voxel printing

Abstract: Prosthetic socket for lower limb amputation needs to be customized based on the residual limb characteristics to satisfy functional and comfort requirements. One of the main causes for ill-fitting socket is the lack of appropriate application of material properties that match the characteristics of the amputee’s biological tissue. Additive manufacturing has the ability to confer inhomogeneous properties to the printed object. This paper presents a digital workflow for the design and fabrication of a prosthetic socket based on the results of numerical simulations and the use of multi-material voxel printing. A voxel model of the socket is generated and the contact pressure between the residual limb and the socket derived from FEA is mapped to the voxels, which were correspondingly assigned a material. This allow to define a material distribution at the voxel level and to generate printing instructions as a stack of bitmap images for voxel printing. The goal is to obtain a socket characterized by a spatial variation of material stiffness, according to the pressure map extracted from simulation, in order to adapt the socket to the patient’s anatomy and, consequently, to reduce contact pressure and discomfort.

Keywords: 3D Printing | FEA | Heterogeneous Objects | Prosthetic Socket | Voxel Printing

Abstract: Nowadays, industrial training is gaining popularity, and in particular, Virtual Reality (VR) technologies are often adopted to recreate training experiences that can transform the learning process by exploiting the concept of learning by doing. Moreover, VR allows us to recreate realistic and immersive environments that provide trainees with hands-on experience in a safe and controlled setting. One of the advantages of using VR technologies to perform training simulations lies in the ability that these tools offer to mix different senses as if they were independent variables and to manipulate them one at a time. In this way, the effects of using one sense on the specific task under analysis can be discovered in a controlled scenario in which the others are controlled. One of the least used senses in VR is undoubtedly that of smell. In this paper, we intend to use a new olfactory device specifically designed to be adopted with VR technologies, integrate it with an immersive VR training application, and propose a series of uses allowed by this combination. In the paper, we report the details of the multisensory approach that integrates the different senses. Additionally, the paper presents the findings of a pilot experiment conducted to validate the adopted approach and assess the results. The study demonstrates that the developed Olfactory Display had no adverse impact on users' interaction with VR content.

Keywords: Olfactory Display | Virtual Reality | Virtual Training

Abstract: Point cloud 3D models are becoming more and more popular thanks to the spreading of scanning systems employed in many fields, like autonomous vehicles and robotics. When used for rendering purposes, point clouds are usually displayed with their original color acquired at scan time, without considering the lighting condition of the scene where the model is placed. This leads to a lack of realism in many contexts, especially in the case of animated point clouds employed in eXtended Reality applications where it would be desirable to have the model reacting to incoming light and integrating with the surrounding environment. This paper proposes the application of Physically Based Rendering (PBR), a rendering technique widely used in Real-Time Computer Graphics applications, to animated point cloud models for reproducing specular reflections, and achieving a photo-realistic and physically accurate look under any lighting condition. Firstly, we consider the extension of commonly used animated point cloud formats, to include normal vectors, and PBR parameters (such as roughness and Metalness), as well as the encoding of the animated environment maps required by the technique. Then, an animated point cloud model is rendered with a shader implementing the proposed PBR method. Finally, the proposed PBR pipeline is compared to traditional renderings of the same point cloud obtained with commonly used shaders, under different lighting conditions in different environments. It will be shown how, using the proposed PBR method, the point cloud better integrates visually with its surroundings. Moreover, it will be shown that using this rendering technique it is possible to render different materials, by exploiting the features of PBR and the encoding of the surrounding environment.

Abstract: The development of comfortable, reliable and custom-made lower limb prostheses represents a crucial aspect, in order to improve the quality of life of amputees. In this context, the aim of this work is to study the donning phase of a custom-made prosthetic socket for transfemoral amputees, by means of numerical simulations. Finite Element Analyses (FEA) were performed to study contact pressures and stresses developed on the stump during the donning. Proper materials models and the presence of the friction and the liner were introduced, in order to analyze their impact on simulations results. Then, a sensitivity analysis to assess the influence of the stiffness of the liner was conducted. The proposed model was able to capture a comprehensive state of stress on the stump at the end of the donning phase. The beneficial effects linked to the introduction of the liner are properly described, too: this element is able to redistribute the stresses which are transmitted to the stump, thus obtaining a more homogenous state of stress. Finally, the sensitivity analysis showed that the variable stiffness of the liner mainly affects the maximum strains on the stump, whereas its influence on the maximum values of contact pressure seems to be limited.

Keywords: FEA | liner | prosthetic socket | transfemoral amputees

Abstract: Additive manufacturing technologies are increasingly taking place in the medical field, enabling the creation of graspable patient-specific anatomical models. Because of their potentiality in improving the understanding of complex anatomies and their shown effectiveness for residents' training, devices testing and planning of innovative surgical interventions, 3D printed models have been incorporated also into cardiac surgery and interventional cardiology. To offer valid and reliable support, however, these printed models are often required to be flexible, with an adequate mechanical response, especially when they aim at replicating soft tissues. The goal of this paper is to provide a high-quality and robust template of a patient-specific whole heart model, obtained starting from a Computed Tomography dataset and exploiting a material jetting printer. Due to the significant shape complexity and the variability in compliance featuring the human heart, the selection of the materials have been diversified, taking into account different model wall thicknesses. Thanks to the capability of the material jetting technology, the 3D model of the heart has been printed with two different material assignments, designed to get highly realistic feedback and reduce the gap between the real heart and the printed ones. Eventually, an accuracy evaluation of the printed model has been performed, by means of a laser 3D scanner. Some further considerations about time and costs required to produce the model are part of the paper, together with a discussion about potential areas of improvement, from materials characterization to the need of speeding up and automating the segmentation procedure.

Keywords: Additive Manufacturing | Heart | Material Jetting | Patient-specific Anatomy | Segmentation

Abstract: An Abdominal Aortic Aneurysm (AAA) is a focal dilatation of the abdominal aorta, which if not treated can rupture with catastrophic internal bleeding. Besides open surgery, minimally invasive EndoVascular Aneurysm Repair (EVAR) has gradually taken place in clinical practice. In this paper, a workflow to evaluate the hemodynamic changes in a patient-specific AAA after stent-graft implantation is proposed. After the extraction from Computed Tomography (CT) images of the AAA 3D model, a patient-specific idealized stent-graft was obtained by means of CAD software. Models were then imported into the simulation environment, where a proper mesh was generated. Once calculations were completed, parameters of interest were extracted and a comparison between values before and after stent-graft implantation was conducted. Results show that, as expected, the introduction of the stent-graft makes the flow pattern smoother and more regular, with no vortices. This is because the stent provides a more physiological geometry for the blood flow, without the aneurysm enlargement. Anyway, simulations were conducted in a simplified way, being the main aim of the paper the implementation of the workflow by which parameters of interest can be obtained. As a development, the introduction of more refined boundary conditions, maybe considering data of the real patient, would increase the reliability of the simulations. A further step would be the passage from Computational Fluid Dynamics (CFD) to Fluid-Structure Interaction (FSI) simulations, so considering wall vessel compliance.

Keywords: AAA | CFD | Stent-graft

Abstract: The development of Virtual Reality in a wide range of field, including engineering related applications, has pushed towards the investigation of novel solutions that are able to take advantage of such new possibilities, while possibly trying to seamlessly integrate them within currently established workflows. Regarding conceptual sketching, which commonly represents one of the first activities taking place across Product Design development work-flows, there are examples of applications that allow to shift from the 2D layout of traditional drawing to a fully immersive 3D environment where the user is able to produce strokes in space by means of a set of natural gestures. Despite sounding extremely intuitive, this kind of approach also comes with potential issues: the lack of a supportive surface onto which the user can rely on to produce strokes with a high degree of precision while not feeling tired after prolonged sessions can be problematic. Based on these premises, a new hybrid approach is proposed: the user is still immersed in the Virtual Environment, but is able to make use of a traditional tablet device which lays on a physical desk in order to produce visible strokes in Virtual Reality, while having the possibility to simultaneously manipulate the position and the orientation of the scene thanks to a hand tracking device to break into the third dimen-sion. As designed, the application supports the generation of simple line strokes and few basic commands, but a thorough testing session is still needed to validate the solution and investigate on the necessary improvements.

Keywords: Conceptual design | Product design | Virtual reality

Abstract: This paper presents a case study regarding the simulation of a robotic workstation to virtually test objects detection and obstacle avoidance. Testing these features inside a virtual environment is useful, especially when human-robot cooperation and interaction are involved. Indeed, it allows users to avoid real dangerous conditions, lowering the possible risks of injuries by the users and cutting down the costs compared to a real testing environment. The work presented here exploits a framework where a virtual environment is connected to a Robot Operating System (ROS) able to simulate the kinematic of the robot and, on the other side, a physical ultrasonic sensor acts as the bridge with the real world. The latter, driven by an Arduino board, allows the virtual robot to recognize static obstacles in the real world, mapping the surrounding environment and computing a suitable trajectory to accomplish the given task. Thanks to the sensing capability, the virtual robot is also able to react to the presence of other obstacles (e.g. humans) entering the workspace at runtime. The seamless connection between the virtual and the physical world makes the framework suitable for the fast testing of new algorithms driving the behavior of the robot when interacting with dynamic environments.

Keywords: Costs | Human robot interaction | Object detection | Ultrasonic applications | Virtual reality

Abstract: Memorization techniques are of primary importance in education. Two relevant and extensively used techniques are the Concept maps and the method of loci. Both methods are based on the visualization of information, which helps memorization and retrieval. For these reasons, they are also considered inclusive learning tools for people with Specific Learning Disability. Augmented Reality is a technology that has gained popularity in many sectors, from industry to the medical one, for its effectiveness in visualizing graphical items on top of real contexts. The paper demonstrates that Augmented Reality can also be beneficial for representing and interacting with Concept maps in a 3D virtual space that is linked to the real world. Specifically, the authors developed an Augmented Reality application in which the key features of both the Concept maps (such as visual-spatial logic and concepts organization) and of the method of loci are integrated with those of Augmented Reality technologies to improve the learning process and the retrieval of information.

Keywords: Augmented Reality | Concept maps | virtual learning

Abstract: One of the major barriers to close the gaps between the academic paradigm of Product Lifecycle Management (PLM) and the actual potentialities offered by modern PLM implementations in industry is represented by the inherent difficulty in the management of product information structured over a formalized product-related knowledge. This is especially true for complex, highly customized and engineer-to-order products. The amount, the complexity and the variability of the information throughout the lifecycle makes the Product Data Management capabilities inadequate to realize the required level of accessibility. Ontologies and Semantic Web Technologies are a promising solution in addressing the aforementioned challenges relevant to PLM. Despite that, ontologies implementations in real industrial applications remain very limited in number and, in any case, either are restricted to specific areas or tackle the issue from a too general point of view. The paper aims to present a generalized approach to structure a product knowledge domain over a general-purpose, agnostic “base” ontology. It has been developed on top of formal model taken from literature, where the knowledge relative to a complex, highly customized and engineer-to-order (ETO) product from Oil & Gas Turbomachinery industry was formalized in an OWL-DL ontology enriched with SWRL rules and reasoning capabilities. To facilitates the interaction and the validation with the formal model, a Graphical User Interface (GUI) has been implemented. It enables the penetration of reasoning-enabled ontologies within industrial mindsets and forms the foundations for future integration of the generated product information layer within industrial PLM ecosystems. Within this context, IT asset used to realize the presented proof-of-concept is described and major challenges encountered during the realization and the way they have been tackled are discussed, together with strengths and limitations associated to the approach.

Keywords: Graphical user interfaces | Information management | Knowledge based systems | Life cycle

Abstract: Medical images do not provide a natural visualization of 3D anatomical structures, while 3D digital models are able to solve this problem. Interesting applications based on these models can be found in the cardiovascular field. The generation of a good-quality anatomical model of the heart is one of the most complex tasks in this context. Its 3D representation has the potential to provide detailed spatial information concerning the heart’s structure, also offering the opportunity for further investigations if combined with additive manufacturing. When investigated, the adaption of printed models turned out to be beneficial in complex surgical procedure planning, for training, education and medical communication. In this paper, we will illustrate the difficulties that may be encountered in the workflow from a stack of Computed Tomography (CT) to the hand-held printed heart model. An important goal will consist in the realization of a heart model that can take into account real wall thickness variability. Stereolithography printing technology will be exploited with a commercial rigid resin. A flexible material will be tested too, but results will not be so satisfactory. As a preliminary validation of this kind of approach, print accuracy will be evaluated by directly comparing 3D scanner acquisitions to the original Standard Tessellation Language (STL) files.

Keywords: 3D printing | Heart model | Patient-specific modeling | Segmentation | Stereolithography

Abstract: In recent years, the use and demand of bicycles have increased thanks to the growing attention to the environment and due to the COVID-19 pandemic situation. At the same time, the design of the bicycles has remained substantially unchanged, improving in materials and components technology. In the off-road sector, two diametrically opposed categories have emerged in terms of comfort and pedalling efficiency. The goal of this research is to introduce a first methodological approach for the optimization of a mountain bike frame. The behaviour of the developed frame aims to combine the pedalling benefits now available only in different and non-comparable bicycle configurations. The first step concerns the modelling of a generic off-road bicycle frame, then its behaviour has been simulated for specific load cases. Subsequently, the part of the bicycle that best performed the double function of compliance and rigidity has been sought through an analysis of the strain energy using FE simulations. Hence, the reference region has been topologically optimized to provide adequate chassis travel performance. The analysis scheme has been iteratively repeated also on other parts of the frame until an acceptable solution is obtained for the utilize presented. The final configuration permits a rear tube and bottom bracket displacement of 10.4 mm and 2.4 mm compared to the 0.5 mm and 0.4 mm of the original frame respectively. The approach described can be proposed as a support for the search for an innovative design for products with unchanged geometries due to the inertia of the designers. At the same time, this methodology aims to expand the possible use of topological optimization, moving away from the classic constraint schemes present in various software.

Abstract: In the industrial contexts of the digital era, data, information and knowledge should seamlessly flow throughout the product lifecycle, and be available at any time and to any agent acting in the value creation stream. PLM is one of the enabler of this scenario, striving to scale the "cobbler"model - where people, information, resources and processes are perfectly integrated - to modern industrial realities operating with multi-disciplinary teams and world-wide dispersed internal and external resources. Yet, despite many industrial realities has invested in the institutionalization of a PLM system, still approx. 60% of time in the value creation process is wasted in searching and waiting for data, data translation, working with wrong data or reinvention of the existing knowledge. After having analyzed the above scenario in the context of a real big industrial reality operating in the turbo-machinery production for Oil & Gas and Engery markets, the present paper aims to propose a solution introducing a working approach based on the modeling of the knowledge domain relevant to a product and its data model by an OWL-DL ontology, and to present the relevant preliminary results. The final target will be the establishment of an ontology-based domain model as the foundation for a digital, human-machine interoperable, product knowledge and data lifecycle management system to bridge the diverse agents operating in the Product Lifecycle Management.

Abstract: In the last past years, computer-Aided technologies to improve existing products by widening the design space have been largely investigated. Topology optimization and generative design are two of the most representative technologies of such kind. This paper aims at investigating the use of generative design and topology optimization techniques to improve products whose design has not changed radically over the years. The product under investigation is a disk brake floating caliper that is the most common solution for commercial vehicles. In general, increasing the stiffness of the floating caliper while keeping its weight under control is desirable both from performance and fuel consumption point of view. The solution here proposed aims at exploiting two new ways to approach the engineering design process and evaluate which one is more suitable for problems of this kind. Starting from the original carrier shape, acquired with laser scanning, the two technologies have been applied on the same initial conditions. The initial design space volume corresponds to the acquired shape, the loads and the constraints for the simulation have been drawn reasonably to resemble the actual operating conditions. Keeping the input parameters constants, two different off-The-shelf software packages have been used to perform the computation and with the objective of maximizing the stiffness of the carrier while reducing its mass. The comparison and the improvements on the final designs have been drawn taken as reference to the original caliper..

Abstract: Functionally Graded Materials (FGMs), initially conceptualized in the '80, have recently attracted a great research interest thanks to the advent of additive manufacturing (AM) technologies. AM permits to gradationally varying the spatial composition or porosity inside an object resulting in a corresponding spatial change in material properties. The data about this new class of materials are radically different from the traditional engineering materials and require information about the object geometry. Moreover, traditional methods for product design are not sufficient to represent heterogeneous objects. The full exploitation of these technologies requires the synergy of material science, product modeling and manufacturing domain. Ontologies can play a crucial role for the integration, making the information accessible and understandable to both experts from different domains and machines. In this paper, a prototypical ontology for the characterization of FGM objects is proposed. Firstly, an already existing FGM ontology is analyzed, highlighting shortcomings and possible improvements. Then, the new ontology is proposed, focusing on the classes and relationships for accommodating material knowledge and geometrical information. The core idea, retrieved from the literature on heterogeneous object representation and transposed in an ontological fashion, is based on the mapping between the geometrical 3D space and the n-dimensional material space. After presenting the new ontology, a benchmark case study is described to test the effectiveness of this approach along with some competency questions an engineer might be interested in. The proposed ontology represents a first, crucial building block for a more complex system aiming to support the communication and knowledge sharing among different actors in engineering..

Abstract: Total Knee Arthroplasty is one of the most commonly performed orthopedic procedures and it is expected to grow in the next future . In the last past years, computer-assisted procedures represent one of the trends that are transforming the way of practicing medicine. Cornering the Total Knee Arthroplasty, digital models of the joints have been used to carry out simulation of their kinematics and mechanical performance. Whilst for the 3D digital reconstruction of the patient geometry several studies have been conducted, an approximated geometry of the prosthesis has been several times employed, with undeniable consequences on the final results. This paper aims at comparing two non-contact reverse engineering technologies to acquire the shape of femoral components employed for total knee arthroplasty. A high-level device (Konika Minolta Vivid 9i) and a mid-low cost laser (NextEngine) has been compared. For the comparison, a systematic procedure of acquisition and elaboration of the results has been adopted in order to have as unbiased as possible results. The procedure involves the use of the proprietary software of the scanners for the elaboration of the raw data and the meshing procedure has been kept the same for all the models. Since the as-is acquired mesh is of high-resolution, a decimation procedure has been carried out in order to make the 3D models lighter and easier to be handled. Once the decimation procedure has been evaluated comparing the original and the simplified models to one another, the digitalized models have been compared with the measurements taken from a coordinate measuring machines. As a preliminary result, the two lasers seem to be adequate to accomplish the reverse engineering process as required by this application. Of course, the mid-low cost laser would be preferable whether the performance will be confirmed to be (statistically) equal.

Abstract: During the concept phase of the industrial design process drawings are used to represent designer’s ideas. More specifically, the designer’s goal is to put the characteristics of ideas on paper so that they can later act as pivotal points in the development of a project. Sketching is also the ideal tool to continue developing an idea: because it is imprecise, the sketch guarantees a high degree of freedom, allowing for changes to made and new ideas to be added. Another possibility is to translate ideas into sketches on computer tools. This approach can allow the designer to use the created 3D model as the basis for further developing ideas. At the present moment, however, this type of solution is not extensively used by designers during the concept phase. Some researchers have identified technical problems as the reason why these instruments have been unsuccessful on the market, while for others this is related to systems still too rigid to be adapted to the often-diverse needs of designers. The research presented in this position paper aims at analyzing what has so far been understood with respect to the process of generating ideas, their initial representation in the concept phase and the tools that have been developed so far to support this phase. Consequently, a discussion on these themes and some hypotheses from which develop new research lines will be presented.

Abstract: Digitalization has already permeated most of the design activities, but in spite of this, the generation of visual representations of concepts in the product design domain still relies on analog tools in real world contexts. Despite immersive 3D technologies, such as Virtual Reality, have become widely available and affordable, most designers still make use of pencils and paper sheets, or their digital counterparts, to sketch their initial ideas on 2D supports. This study aims at investigating the reasons behind the mismatch between the rapid growth of immersive technologies and their scarce adoption in the conceptual design activities. Based on the analysis of the state of the art, a classification of the approaches proposing new ways to conduct conceptual representation of products has been drawn. The geometry representation, i.e. parametric or polygonal, and the interaction methods have been taken as metrics to categorize previous works. Weak connections between the modeling paradigm implemented and the interaction methods, lack of spatial faithfulness, ergonomic concerns and the need for quantitative metrics to compare objectively the data resulting from different testing sessions across the various studies are the main issues identified. In order to get concrete evidence of such thoughts, an experimental session has been devised with users from different backgrounds. They were asked to make conceptual sketches of a computer mouse in a traditional fashion, i.e. with pen and paper, and using two off-the-shelf Virtual Reality applications, based on 3D sketching and 3D sculpting respectively. The results are discussed qualitatively by visually comparing the sketches made by the testers, enriched by information deducted by surveying the users before and after the experiments. By comparing the sketches made by each user with the three procedures, preliminary results indicate that VR systems don't bring dramatic improvements compared to traditional 2D sketching tools. Furthermore, despite being enjoyable, VR systems caused physical fatigue, which is a problem that basically does not affect 2D sketching. Despite the size of the sample cannot provide statistical evidence, the outcomes provided good indications about the technology readiness level of Virtual Reality as a conceptual design tool, paving the way for future research directions.

Keywords: Conceptual design | Product design | Virtual reality

Abstract: A robust machine health state recognition tool is a pillar for condition-based maintenance and Deep Learning approach finds its natural application in such a context. This paper investigates the recognition of machine failures by image classification through a convolutional neural network in a condition-based maintenance environment. The case study involves a refrigerator for large retail establishments. Experimental measures, while the machine is approaching failure, are difficult to be collected, especially in the quantity needed for training and testing the neural network. For this reason, a digital twin of the asset has been created to simulate the behavior of the machine and generate as many data as needed: physically-based models of the machine and failure modes have been included and the simulated behavior has been tuned by using experimental data. Finally, it has been employed to generate signals that, translated into images, test the suitability of the neural network.

Keywords: Condition based maintenance | Digital twin | Image classification | Neural network

Abstract: Reality-based 3D techniques and Finite Element Analysis share the way the object under investigation is discretized. Although their purpose, the generation methods and the quality metrics are different, both of them ground on the concept of mesh. Unfortunately, a mesh derived from a reality-based technique are not suitable to be used in a finite element solver directly. This paper aims at comparing different methods to prepare computational mesh of geometries derived from non-contact reality-based technologies. A benchmark test object has been acquired with different devices, a triangulation laser scanner, a multi-stripe triangulation scanner and a digital camera, and post processed in order to fix artifacts. Then, two different decimation approaches have been used: a triangular simplification and retopology. The acquired geometry, before and after the simplifications, has been compared with a CAD model employed as reference: mean and standard deviation between the nominal and the acquired geometries have been tracked. Finally, a tensile test has been simulated making use of a general-purpose finite element analysis software and the results have been compared with the exact solution.

Keywords: Finite element analysis | Laser scanner | Retopology | Reverse engineering | Structure from motion

Abstract: The usability of heavy construction equipment is strongly affected by the design of their human-machine interfaces. Lack of confidence with the current input devices is due to their counterintuitive design and the absence of loop feedback between the end effector and human hands. In the last few years, many researchers have been demonstrated that haptic devices, joined with a suitable design of the control levers, could help to face this problem. In this paper, an innovative control logic for hydraulic excavators has been proposed based on the inverse kinematic of the arms of the hydraulic excavator. The aim of this control is to reduce the cognitive effort of the users if compared with the one required by the current control systems. The implementation of this control logic has been based on previous research projects, technical documentations and interviews with experts. The proposed control logic has been evaluated by means of experimental activities with a virtual simulator which test the usability and efficiency of the proposed solution.

Keywords: Coordinated control | Excavator | Haptic device | Human-machine interface | Usability evaluation | Virtual reality

Abstract: This paper presents a preliminary investigation on the workflow that allows to replicate object by using 3D laser scanner and a desktop fused filament fabrication 3D printer. Pitfalls and limitations of those technologies will be pointed out in order to find the bottleneck of the workflow, paying specific attention to what concerns the digital workflow from the acquisition to the generation of the g-code. The findings and conclusions are drawn from a case study that has been carried out using the minimum amount of human intervention, especially during the digital post-processing of the data. The objects under investigation is a broken car door handle. Firstly, it has been digitalized using a 3D laser scanner properly calibrated and set. The accuracy, precision and resolution of the measurement tool have been recorded and the as-is acquired data has been checked against topological errors. The as-is acquired model has been compared with the original geometry. The 3d polygonal mesh has been prepared for being printed: the material, machine and process parameters have been chosen. A simulation of the deposition process to estimate warps and deviation from the nominal geometry was carried out. Finally, the object has been additively manufactured using a desktop Fused Filament Fabrication machine: the printed object has been again compared with the original geometry.

Abstract: Axiomatic design has the potential to help designers understand the increased design freedom and limitations of additive manufacturing prior to starting the actual design process. The purpose of this study is to verify the usefulness of Axiomatic Design in the design process of complex additively manufactured components. The article uses a case study involving the design of a non-assembly turbine to demonstrate that Axiomatic Design can be applied as a supportive tool to acquire information on new limitations imposed by additive manufacturing, such as minimum wall thickness and maximum size of parts. The use of axiomatic design is demonstrated by describing the process of decomposition of the non-assembly turbine and examining the suitability of the general design according to the independence axiom. The resulting decomposition chart is subsequently used as a basis by the authors to design individually two competing designs of a turbine. Finally, the information axiom is used to determine the design with the lowest information content according to design (part and support volume), performance (pressure drop) and economic parameters (cost).

Abstract: Realistic visualization of products is now a must-have for all companies facing worldwide and highly competitive market. Despite Virtual Reality technologies are appealing, its industrial use is still limited to conceptual design and prototyping activities. One of the reason is that generating Virtual Reality (VR) environment is a complex and time-consuming task, especially for complex products or systems. Many technical data are involved in their design and conflguration. A meaningful example is the preliminary conflguration of assembly lines devoted to deliver a quotation to the customer. To be competitive, the quotation should be completed in tight time and contain variants of the conflgured system ranging different costs. Moreover, high-impact and successful quotation goes beyond the merely technical aspect. In this view, the automatic generation of a virtual reality environment can foster the adoption of this technology in industry, since its setup time is short and doesn’t require any skills. In this paper, the integration of a VR module in product conflguration and quotation process is proposed. The framework is a Knowledge-based Engineering (KBE) system that, taken the customer requirements as input is able to automatically generate a bunch of different solutions. Starting from technical data coming from a KBE system, a virtual environment is generated automatically fltting the features of the conflgured solution. Furthermore, the immersivity of the VR scene is enhanced by integrating the animation of the objects, like robots and pallets. After a brief description of the KBE system, the paper details the information is involved in, the implementation of the VR module and its integration within the KBE framework.

Keywords: Assembly line | Knowledge-based engineering | Quotation | Virtual reality

Abstract: Current trends in product development process highlight the increasing adoption of digital data and virtual processes. Nowadays, a huge amount of product data are collected without a clear management strategy and, oftentimes, they dont even cover the whole product development process. A global and integrated planning about information needed to sustain product design process is not a trivial task and, usually, companies underrates this issue. From the perspective of virtualization of processes, and then their automation, the lack of structured knowledge is certainly awful. This paper aims at making a critical analysis how product data evolve throughout the product design or configuration process and how they impact the product development activities. Efficient digital product twin allows companies to vir-tualize processes and leverage their automation, but it is important to understand how the knowledge management should be carried out. Three case studies, directly experienced by the authors, have been investigated analyzing digital data and virtual tools that allow companies to automate the design process, each one bringing a peculiar perspective of the problem.

Abstract: Along with increased digitalization, virtualization of processes and automation in industry, Industrial Internet of Things opens for new possible scenarios and business models. The opportunities of this technology rely, among the others, on new way for data and knowledge management. Knowledge Based Engineering (KBE) is greatly considered to support design activities related to digital technologies. The paper aims at analyzing the role of Industrial Internet of Things for supporting maintenance operations and evaluating whether the adoption of data structure and the integration with the KBE system can face the actual gaps and needs. After a brief overview of different technologies for knowledge management, a possible scenario has been identified. It represents the framework within IIoT technologies can be applied. This conceptual environment considers a multilevel structure: local facilities, the whole company, suppliers, retailers and global network have been involved into the analysis. Upon that scenario, how data and knowledge can be mapped and managed for each level have been investigated. Moreover, these data can be used to improve the predictive maintenance model as well as to enhance the design of new products through the acquisition and monitoring of an effective set of parameters. Finally, in order to demonstrate the feasibility of the proposed approach with the use of simulation as well as physical devices, a prototypical application related to the maintenance of refrigerated display cabinets has been developed.

Abstract: Digital design and manufacturing are critical drivers of competitiveness but only few companies and organizations have the capability to support digitalization across the whole Product Lifecycle. In several cases the information flow is discontinuous, the roles and the issues are not properly defined, the tools are heterogeneous and not integrated in the company organization. An approach that considers an appropriate data and information organization, an efficient internal organization and the availability of integrated software tools that are implementing the industrial best practices, could innovate important and critical aspect of the industrial processes. This paper gives an overview of the main themes related to Knowledge Management in industrial context, focusing on product configuration process. The current role of the knowledge in product configuration will be discussed. Then, a brief overview on Knowledge-based Engineering will be presented. Regarding Knowledge Based methodology, acquisition and formalization techniques and tools will be analyzed. Finally, an application focused on assembly lines configuration will be presented.

Keywords: Automatic Configuration Process | Knowledge Based Engineering | Knowledge Formalization | Product Configuration

Abstract: The study illustrated in this paper aims at analyzing the knowledge management issue related to product development. Especially, the focus is on the domains in which Knowledgebased Systems (KBE) and Design Automation (DA) tools could be adopted. In the past various studies, a lot of KBE and DA systems have been developed in multiple fields such as automotive, aerospace, energy, materials and manufacturing: the information treated in these studies are about data relatives to specific design, for example, of automotive engine components, aircraft structures, energy plants, advanced material and manufacturing or assembly lines. In all of these domain the organization and formalization of the knowledge is a critical issue. The adoption of a good strategy to manage data and information relative to products and processes involves benefits in the product development process. Different methodologies are described in literature. The two of the most used are the Object-Oriented (OO) and Ontology Engineering (OE) approaches. The former is one of the most common and adopted in the industrial domain, including a lot of implementations in the recent past years. The latter is more commonly used in other fields, like bio-engineering, used with the scope of management of experimental data; few implementation in industrial engineering have been considered. The article considers a brief description of the state of the art about Knowledge Based Engineering and Ontology Engineering. A case studies will be described and the benefits and disadvantages due to the use of the different methodologies will be discussed.

Abstract: One of the most important factors that allows the big enterprises to be competitive in the market is the capability to develop products that are tailored on the specific customer requirements with a short lead-time. This research aims to study an automated configuration tool for assembly lines. A KBE approach was used. The configuration process for an assembly line has been identified with the experts of a big manufacturing Italian company. One of the critical issue is that the domains knowledge is mostly tacit. The implementation stage was carried out with a commercial development tool. Thanks to a modular design of the KBE system a strong but flexible framework was achieved. The rules and data repositories, as well as the code of the single module, can be update easier. An industrial case study was used to validate the proposed approach: the configuration of a cylinder head assembly line was performed.

Abstract: Building energy simulation models are playing an increasing role in the construction industry and estate services and are constantly being improved. However, the accuracy and usability of simulation results is highly dependent on its inputs, many of which remain difficult to determine. Amongst inputs, the definition of occupant behaviour is recognized to be complex, and generally underestimated and neglected. With the trend towards increasingly energy efficient buildings, a proper representation of occupant presence and activities is becoming crucial in the design of buildings, which need to be comfortable, adaptable and resilient towards variable thermal loads. This paper presents a study of the occupancy of a university building in the UK in order to assess discrepancies between assumed and actual occupancy of the facility. Data has been obtained from a range of sources, including the Building Energy Management System, timetabling, and direct observation. The corresponding occupancy patterns have been simulated using DesignBuilder and EnergyPlus. Results indicate a potential energy saving in the order of 10% for set-up control that matches actual building occupancy more closely than current settings.