Abstract: Featured Application: The methodology presented in this work enables the direct extrusion-based 3D printing of soft, low-hardness RTV-2 silicone elastomers using industrial additive manufacturing systems. By adapting commercially available general-purpose silicones through viscosity tuning, the proposed approach expands the material palette for silicone additive manufacturing beyond proprietary formulations. This capability is particularly relevant for applications requiring highly compliant, biocompatible, and geometrically complex parts, such as soft robotics components, customized prosthetic and orthotic devices, medical simulation models, wearable interfaces, and flexible seals or gaskets. A particularly relevant industrial scenario for the proposed methodology is the small- to medium-batch production of customized silicone components, where traditional mold-based casting becomes economically inefficient due to tooling costs and long lead times. This study investigates the relationship between viscosity and manufacturability of two-component silicones in extrusion-based additive manufacturing. A methodology is proposed to adapt commercially available, low-viscosity general-purpose silicones for direct 3D printing using the material extrusion system provided by Lynxter S300X. EcoFlex™ 00-50 silicone was modified through controlled additions of a thixotropic agent (THI-VEX), producing formulations with progressively increased viscosity. After a preliminary qualitative viscosity assessment, formulations were printed using identical process parameters and evaluated through a set of dedicated geometric benchmark specimens targeting critical failure modes, including unsupported thin walls, overhangs, gaps, and slender structures. Print outcomes were assessed via multi-rater visual inspection with inter-rater reliability analysis to ensure consistency. Results reveal a strong correlation between thixotropy and geometric fidelity, identifying the formulation containing 4.0 wt% THI-VEX as optimal under the tested conditions. The study provides practical design and process guidelines for silicone additive manufacturing and highlights the importance of integrated material–process optimization for reliable fabrication of soft, highly deformable materials.

Keywords: geometric printability | material extrusion | RTV-2 silicone elastomers

Abstract: This paper presents a comprehensive application of an automated surgical planning workflow for bone tumor resection, integrating two previously developed algorithms into a real clinical case. The study focuses on a patient with a left tibial osteosarcoma, demonstrating how the automated framework streamlines the entire preoperative process, from tumor resection planning to allograft selection. The cutting plane optimization tool reduced manual planning time from hours to just 19 min while ensuring complete tumor removal with minimal healthy bone resection. For reconstruction, the system automatically reconstructed the patient’s premorbid anatomy and selected the best-matched allograft from a virtual donor database, achieving a high degree of anatomical precision (mean distance: 0.29 mm). The results highlight the clinical potential of this integrated approach, which improves efficiency, reduces subjectivity, and enhances reproducibility in complex bone tumor surgeries.

Keywords: Allograft | Design Method | Optimization | PSO | Tumor Resection | Virtual Prototyping

Abstract: Wrist impairments are common in post-stroke and elderly populations, often requiring rehabilitation to restore joint mobility and strength. However, clinic-based programs pose accessibility challenges, especially for patients with limited mobility. This paper presents W.R.I.S.T. (Wrist Rehabilitation Intelligent Support Tool), a soft robotic prototype designed to facilitate wrist flexion-extension exercises in home settings. The system features an inflatable silicone handle integrated into a 3D-printed structure, equipped with a flexion sensor for monitoring and a pneumatic circuit for real-time resistance modulation. A microcontroller manages pressure regulation and sensor data acquisition, enabling adaptive therapies and personalized training. Experimental validation confirmed a predominantly linear relationship (R2 > 0.85) between sensor output and flexion angle across pressure levels, ensuring reliable motion tracking. Additionally, a game-based interface was developed to enhance user engagement, transforming repetitive exercises into an interactive task with customizable difficulty. The integration of adjustable mechanical resistance and interactive feedback supports progressive rehabilitation while promoting adherence. W.R.I.S.T. offers an affordable, customizable, and valid solution for decentralized rehabilitation, particularly suitable for elderly users or those with limited access to clinical services.

Keywords: 3D printing | Pneumatic | Rehabilitation | Soft Material | Wrist

Abstract: This paper presents a comprehensive overview of methodologies developed to support blind and visually impaired people (BVIP) in perceiving two-dimensional visual content through tactile representations. Over the past decade, the TIP group at the Department of Industrial Engineering of Florence has advanced both deterministic and AI-assisted techniques to generate tactile bas-reliefs from pictorial and technical images. The research spans various computerassisted methodologies for producing depth images or full 3D models of tactile supports. The research seeks to establish a codified language, its expression dictated by the ‘grammar’ of semi-automatic procedures that offer limited scope for a manual user’s free interpretation. Latest results achieved in the translation of abstract paintings are presented, including an effective pixel intensity-based approach for translating chromatic information into tactile depth. Applications include cultural heritage accessibility and inclusive technical education. Results demonstrate the growing viability of hybrid and AI-enhanced solutions to generate meaningful, perceivable tactile models, highlighting the importance of structured tactile languages and multimodal interfaces for improving accessibility.

Keywords: 3D modelling | bas-relief | Blind People | Depth image | tactile models

Abstract: Piezoelectric material extrusion is a novel material extrusion technique that deposits thermoplastic materials in droplets, by means of a piezoelectric nozzle regulating the material flow. This improves the performance of the machine, with respect to Fused Filament Fabrication, by enabling higher precision in material placement and better control over deposition volume. A common limitation of this technology lies in the fabrication of overhanging structures, where precise droplet deposition is inherently more complex and prone to inaccuracy. The research investigates the impact of a key process parameter, specifically Droplet Aspect Ratio, on the dimensional accuracy of printed specimens and on the quality of overhang surfaces. The research considers bridging and the prioritization of infills in the deposition strategy as additional variables. An experiment based on the fabrication of 50 specimens, optimized for overhang quality evaluation, was performed. Specimens were analysed through 3D scanning techniques. The study demonstrates a strong correlation between Droplet Aspect Ratio and the dimensional accuracy of overhanging surfaces. The integration of bridging structures significantly improved surface quality by providing additional support, with the greatest benefits observed at 27° inclination. Prioritizing infill deposition before outer contours resulted in a marked reduction in defect levels at high DAR values.

Keywords: additive manufacturing | droplet aspect ratio | overhang | pellet-based material extrusion | piezoelectric nozzle

Abstract: Soft robotics represents a paradigm shift in robotics, focuses on creating adaptable, flexible robots inspired by biological systems to engage safely and efficiently with intricate environments and living organisms. This study focus on the investigation of the performance characteristics of 3D-printed Soft Pneumatic Actuators (SPAs) fabricated from thermoplastic polyurethane using Fused Filament Fabrication. Through systematic experimental analysis, we evaluate how geometric parameters and operating conditions affect actuator behavior, specifically examining the relationships between the number of bellows (N), wall thickness (T), and operating pressure (P) on the resulting bending angle (α) and maximum force output (F). Tests were conducted on 45 actuator specimens, with bellows counts of 9, 11, and 13, wall thicknesses of 1.6, 2, and 2.4 mm, and operating pressures ranging from 1 to 3 bar. Results demonstrate approximately linear relationships between design parameters and actuator performance metrics. Increasing the operating pressure showed strong positive linear correlations with bending angle, while wall thickness demonstrated a strong negative linear correlation. For force output, operating pressure maintained a strong positive linear correlation, wall thickness showed a moderate negative linear correlation, while the number of bellows had only a weak positive correlation. Both bending angle and force output exhibited approximately linear relationships with these parameters, with deviations from linearity remaining fairly low across all configurations. The predictable, near-linear responses provide a robust foundation for performance-driven design optimization of SPAs for applications requiring precise control of movement and force generation.

Keywords: 3D printing | pneumatic actuator | precise control | soft actuator | soft material

Abstract: In tumor resection surgery, an approach to the reconstruction of the bone anatomy, after removal of the tumor, is represented by allografts. A good match between the donor and recipient is crucial in enhancing integration and minimizing failure rate. However, the recipient bone is often altered by the tumor, making the comparison unreliable. Moreover, evaluating multiple donors is often a complex and time-consuming process. Thus, in this work, an algorithm is proposed that is able to automatically reconstruct the virtual healthy bone anatomy of the recipient and to use this reconstruction to select the most suitable donor. The proposed algorithm first reconstructs the healthy anatomy by aligning the bone to the mirrored contralateral using the Iterative Closest Point (ICP) algorithm. Then, to select the optimal donor, the algorithm queries a digital bone bank by aligning the reconstructed template to donor candidates using a localized search strategy. Finally, L1-Chamfer Distance and a newly devised metric called Surface Distance are computed to evaluate the similarity and assess the optimal donor. The algorithm was validated on a dataset of 49 healthy femurs by creating 980 simulated resections. A retrospective study on two real cases was also conducted. The algorithm achieved a median L1-Chamfer Distance of 0.7217 mm and a Surface Distance of 0.3225 mm for the reconstruction of the healthy anatomy and 0.8621 mm and 0.5338 mm, respectively, for the best donor. The retrospective studies showed how the algorithm was able to outperform the manual procedure in both time and accuracy of the allograft. These case studies highlighted how the algorithm performs efficiently even in real case scenarios, enhancing the shape matching between the recipient and donor bone and thus possibly improving post-operative outcomes.

Abstract: Stroke survivors often experience debilitating upper limb conditions, requiring therapy and rehabilitation exercises to regain limb function. However, frequent visits to medical centers for treatment sessions pose challenges. This paper presents GripDome, a prototype designed to measure grip strength in a user-friendly and highly tailorable manner, enabling strength recovery for patients in domestic environments without the need for medical assistance. GripDome consists of an elastic, inflatable silicone dome connected to a plastic base. Patients exert pressure inside the device by squeezing the dome with varying forces, which is measured using an external pressure transducer and a microcontroller. The prototype offers adjustable resistance levels, facilitating quantitative assessment of grip strength and personalized rehabilitation progress tracking.3D printing is employed for plastic components, enhancing affordability and customization. Experimental tests demonstrate GripDome’s ability to distinguish forces of different intensities and repeatability of measurements.

Keywords: 3D printing | Grip Strength | Pneumatic | Rehabilitation | Soft Material

Abstract: With approximately 431,000 cases, kidney cancer ranks 14th in terms of diagnostic frequency and accounts for 2.2% of all new cancer cases worldwide.12. For malignant clear cell renal cell carcinoma (ccRCC), which necessitates WHO/ISUP grading based on tissue microscopic analysis, early diagnosis is critical for targeted treatment. With the use of a convolutional neural network with three blocks, this study presents a machine learning-based system to grade kidney tumors using CT scans. The system divides tumours into low-grade (grades 1 and 2) and high-grade (grades 3 and 4), which corresponds to the tumour’s aggressiveness and helps determine the prognosis. The challenge kits21 database’s 237 preoperative CT scans were used to train the model, which yielded an accuracy of 93.67% and an f-score of 91.80%. For reliable performance validation, the approach consists of data preprocessing, augmentation, and a binary classifier with a majority voting ensemble model. The objective of this non-invasive method is to improve diagnostic accuracy in clinical settings by decreasing inter-observer variability. The dataset will be enlarged in future work to enable wider application.

Keywords: AI | ccRCC | Deep learning | grading | image processing | kidney cancer

Abstract: More than 90% of atrial thrombi in patients with non-valvular atrial fibrillation originate in the Left Atrial Appendage (LAA), a diverticulum of the left atrium of the human heart, whose morphology predisposes the stasis of blood within it. The Left Atrial Appendage Occlusion procedure shows promise for reducing the risk of stroke due to blood clots in the body circulation after forming in the LAA; however, it must be performed by experienced operators due to the numerous associated risks. The objective is to develop a simulator for training novice operators in the procedure to plan the optimal occlusion path on representative models. Starting from a dataset of 20 diagnostic images provided by the Azienda Ospedaliero Universitaria of Careggi, a three-dimensional reconstruction of the anatomical areas involved in the surgical procedure and their spatial identification are performed. These results are used to design a device for the adjustment of a 3D printed model of the LAA with correct orientation and spatial coordinates. The simulator is a highly customizable and patient-specific prototype system; the ease of use and small size help its acceptability and reduce the time required for practice in use.

Keywords: 3D Printing | LAA | Simulator | Surgical training

Abstract: In bone tumor resection surgery, patient-specific cutting guides aid the surgeon in the resection of a precise part of the bone. Despite the use of automation methodologies in surgical guide modeling, to date, the placement of cutting planes is a manual task. This work presents an algorithm for the automatic positioning of cutting planes to reduce healthy bone resected and thus improve post-operative outcomes. The algorithm uses particle swarm optimization to search for the optimal positioning of points defining a cutting surface composed of planes parallel to a surgical approach direction. The quality of a cutting surface is evaluated by an objective function that considers two key variables: the volumes of healthy bone resected and tumor removed. The algorithm was tested on three tumor cases in long bone epiphyses (two tibial, one humeral) with varying plane numbers. Optimal optimization parameters were determined, with varying parameters through iterations providing lower mean and standard deviation of the objective function. Initializing particle swarm optimization with a plausible cutting surface configuration further improved stability and minimized healthy bone resection.

Keywords: Computer-aided surgery | Optimization | Orthopedic surgery | Surgical planning | Tumor resection

Abstract: Stroke survivors often face significant upper limb impairments, necessitating frequent therapy and rehabilitation to regain function. However, frequent visits to medical centers for treatment sessions pose challenges to the patient. We present GripDome V2, an enhanced prototype for customizable grip strength measurement and rehabilitation. It enables unsupervised home use, improving accessibility. The device features an inflatable silicone dome connected to a PLA base, with grip strength measured via a pressure transducer and microcontroller, by which the patient’s progress can be measured and quantified. The prototype offers adjustable resistance levels, facilitating personalized rehabilitation progress tracking. 3D printing is used for plastic components and silicone molds, enhancing affordability and customization. Experimental tests demonstrate GripDome’s ability to provide consistent and reliable measurements even under prolonged use. The pneumatic system allows dynamic adjustment of resistance levels, tailoring rehabilitation paths to individual needs. Additionally, a basic game-like exercise has been integrated to motivate users, making the rehabilitation process more engaging and enjoyable. The device shows promise for reliable quantitative grip strength assessment and at-home rehabilitation for stroke survivors.

Keywords: 3D printing, additive manufacturing, rehabilitation | Hand rehabilitation | Personalized rehabilitation | Pneumatic | Rehabilitation devices | Silicone | Soft actuator

Abstract: This paper presents a novel workflow for designing and fabricating patient-specific cranial implants and surgical guides using advanced CAD and 3D printing technologies. Developed at the T3Ddy Lab at Meyer Children’s Hospital, the methodology includes close collaboration between engineers and neurosurgeons, allowing for rapid prototyping and real-time adjustments. The workflow involves designing a cutting guide for precise bone resection and a custom cranial implant for anatomical reconstruction, both using titanium alloy for its biocompatibility and mechanical strength. The setup enhances efficiency, ensuring precise device fit and improving surgical outcomes. The paper presents the general framework established to design custom made medical devices for skull repairing surgery. The CAD modeling phase of the surgical guide and cranial implant are described in detail, highlighting developed solutions to improve the effectiveness of the technology. The proposed workflow was validated in multiple clinical cases, demonstrating improved surgical precision, reduced operative time, and enhanced recovery.

Keywords: 3D Printing | CAD | Cranial Implant | Cranioplasty | Craniotomy | Surgical Guide

Abstract: This study presents the development of a prototype anthropomorphic soft robotic gripper intended for applications in rehabilitation and assistive robotics, where safe and adaptive interaction with humans is required. The device consists of three elastomeric fingers, fabricated in TPU via FFF 3D printing and actuated through pneumatic soft actuators that ensure compliant contact with both biological tissue and rigid objects. A custom 3D-printed pneumatic rotary actuator enables finger reconfiguration, thereby extending the range of grasping modalities. The actuation system comprises six 2/2 solenoid valves controlled by an Arduino Uno and integrated into a dedicated pneumatic circuit. Experimental characterization demonstrated a peak grasping force exceeding 17 N on rigid targets, while functional tests in table-picking scenarios confirmed adaptability to objects of varying shapes and sizes. Owing to its anthropomorphic configuration, mechanical compliance, and ease of fabrication and control, the proposed gripper represents a versatile solution for rehabilitation-oriented devices as well as assistive robotic end-effectors in pick-and-place tasks.

Keywords: additive manufacturing | assistive robotics | pneumatic | rehabilitation | soft actuator | soft gripper

Abstract: Long-term exposure to noise affects physical and mental health. In Europe, at least one in five person is exposed to high chronic noise levels that can cause adverse health effects. The European Commission\'s zero pollution plan aims at reducing the negative impacts of exposure to transport noise, considered the major source of noise pollution in both urban and non-urban areas, by 2030. Moreover, in recent years many cities have introduced tramway systems as a sustainable alternative for urban mobility and to reduce traffic congestion. However, in urban contexts tramways provides a supplementary noise source, especially due to the squeal noise in curves, leading to annoyance due to additional noise and vibrations. The LIFE SNEAK project “optimized Surfaces against NoisE And vibrations produced by tramway tracK and road traffic” aims at reducing noise inside urban areas, where tram and traffic noise and vibration superpose, by means of low-noise/vibration surfaces and retrofitting solutions having LCC comparable to those of standard surfaces. At the beginning of the project started in 2021, ante-operam activities for the characterization of the selected site for the pilot case in Florence (Via La Marmora) have been performed: internal and external measurements of noise, traffic flows and were carried out in the period February-April 2022. A perceptive survey aimed at understanding how residents, workers in the area perceive noise due to road traffic in the ante-operam scenario was also performed. A system of sound-absorbing panels to be applied on the tram (bogie skirts) has been designed and a low emission asphalt to mitigate air-born noise has been designed and implemented in November 2024. In January/February 2025 the first post-operam noise measurement campaign has been carried out. First results obtained by the Project are illustrated in the current paper.

Keywords: LIFE SNEAK project | noise | road noise and vibrations | tramway noise and vibrations | vibrations measurement campaigns

Abstract: The Fourth Industrial Revolution conceptualizes the rapid change of industries resulting from the convergence of technologies such as artificial intelligence, genetic editing, and advanced robotics that enable increasing interconnectivity and machines that can analyze and diagnosing problems without human intervention, through intelligent automation. In this scenario, the use of augmented reality technologies is of great interest. The paper aims to explore the use of augmented reality in support of traditional inspections for assisting textile experts in fabric defect detection. The contribution of this study consists of three main phases, necessary for the future development of the system: (1) the analysis of possible automatic defect detection techniques; (2) the analysis of hardware solutions for the realization of a system based on important criteria such as operator comfort, system footprint, and so on; (3) the proposal of a possible comprehensive solution. Considering these aspects this paper identifies and investigate the best scenario for the introduction of artificial intelligence and augmented reality technologies to help the operator in the detection of textile defects.

Keywords: Artificial intelligence | augmented reality | machine vision | textile defect detection

Abstract: The growing cooperation between physicians and engineers have been producing increasingly sophisticated anatomical phantoms for the training and planning of Structural Heart Surgery. Trans-Septal Puncture (TP) is a percutaneous, non-invasive cardio chirurgical procedure used to access the heart Left Atrium from the Right Atrium through the Fossa Ovalis (FO), a region of the Inter Atrial Septum with reduced thickness. TP is technically challenging and requires dedicated teaching and a skillful operator; as a result, application of phantoms to TP training have been gaining increasing interest. The aim of the present work is to investigate the current state of the art in TP simulators. The Scopus and PubMed databases were analyzed and the bibliography of the most impacting articles was reviewed. The results can be summarized as follows: i) mold casting and additive manufacturing (AM) are the only technologies documented for phantoms creation; ii) silicone rubbers and Polyvinyl Alcohol Cryogel are the most used materials for mold casting while Polyjet polymers are the most used material for AM; iii) quantitative data on force and haptic feedback from IAS and FO simulacra is scarcely documented; iv) procedure image guidance can be simulated during the training.

Keywords: Additive Manufacturing | Material Characterization | Medical Phantoms | Silicone Casting | Trans-Septal Puncture

Abstract: The use of customized surgical guides for the removal of bone tumors is an increasingly common practice in advanced hospitals. These devices are modeled directly on the 3D model of the patient's anatomy and produced using additive techniques; therefore, they have the ability to perfectly anchor to the bone anatomy and allow the tissue of the tumor mass to be removed according to cutting paths predetermined by the physician during preoperative planning. This work proposes a semi-automatic framework for modeling custom surgical guides composed of two main modules: 1) a web application, called Precise, that allows the surgeon to visualize and manipulate 3D anatomical models and enter a set of cutting planes that determine the correct tumor resection paths and other useful information for modeling the surgical guide; 2) a fully automatic procedure that based on this information creates the guide's STL model. The entire procedure aims to create a specific type of cutting guide designed to guide an oscillating saw in a series of planar cuts, thus isolating the tumor. The cutting guides produced are composed of three main elements: a base, the blade slot, and pin’s holes.

Keywords: Medical 3D Model | Medical Application | Rapid Prototyping | Surgical Planning

Abstract: Despite technological advances in diagnostic imaging, to distinguish the type of renal tumor without performing a biopsy is still an unsolved challenge. In particular, this is even more striking in the case of clear cell renal cell carcinoma and small oncocytomas. To tackle this problem, a fully automated tool is proposed that can provide decision support for physicians to distinguish between these two types of masses in the most critical cases. In this work three approaches for the development of this tool are implemented and compared, specifically two approaches are based on the use of radiomic features and one on the use of deep features. The nnU-net is exploited to achieve tumor segmentation necessary to obtain the different types of features. The architectures are trained and tested by combining two different datasets, the public dataset KiTS2019 and data from the Careggi University Hospital. The best method is able to obtain 73.77% balanced accuracy, 94.59% sensitivity, 52.94% specificity and 86.84% accuracy.

Keywords: Cancer classification | clear cell renal cell carcinoma | computer aided diagnosis | deep learning | oncocytoma | radiomics

Abstract: Soft robots have gained significant interest due to their high flexibility and adaptability to various working conditions. Recent advancements in engineering and innovative materials have enabled the design and production of sophisticated soft robotic systems with enhanced capabilities. This study aims to evaluate the fatigue behavior of bellow-type pneumatic soft actuators fabricated through fused filament fabrication (FFF) using thermoplastic polyurethane (TPU), compared to silicone rubber cast actuators. The actuators were equipped with resistive flex sensors to monitor bending motion, and fatigue tests were performed with cycles of inflation and deflation until failure. Results showed that 3D printed TPU actuators could withstand a significant number of cycles before failure, with an average of 6410 cycles at 3 bar pressure, compared to 3439 cycles at 1 bar pressure for the silicone actuators. The study identified a set of fabrication parameters that positively affect the durability of TPU actuators, providing valuable insights for replicating these results. Additionally, the study established a plausible range of utilization for 3D-printed FFF actuators in terms of the number of cycles they can endure, offering critical data for engineers and designers to make informed decisions about the design and application of these actuators in various practical scenarios. The findings demonstrate the potential of FFF for producing durable, long-lasting pneumatic soft actuators.

Keywords: 3D printing | Fused filament fabrication | Pneumatic actuator | Soft actuator | Soft material

Abstract: Technological advances have increased the use of plastic-based additive manufacturing for production in a variety of industries that require high mechanical properties while maintaining geometric precision. The Arburg Plastic Freeformer (APF) process, unlike other filament-based technologies, uses standard plastic granules used in mass production in injection moulding machines. This study focuses on optimising the interaction of three critical process parameters: layer thickness (LT), droplet aspect ratio (DAR) and discharge rate (DR). Previous studies have mainly varied individual parameters to evaluate mechanical and geometrical properties. In contrast, this work analyses these parameters as a whole and evaluates their combined effects on residual porosity and geometric accuracy. APF relies heavily on supports to sustain the printed part, with a smaller achievable self-supporting overhang angle compared to the Fused Filament Fabrication (FFF) printing process. For this reason, this study investigates two compatible materials, ABS Terluran GP35 and a water-soluble PVP compound named Armat11. Cylindrical and cubic samples were 3D printed using different combinations of LT, DAR and DR. A total of 150 cubic samples were printed to assess the geometric dimensional accuracy and repeatability of printing in the plate position using permutations in the printing plate. Subsequently, 30 cylindrical samples were printed for micro-CT analysis, reconstructed by CT file segmentation and compared with the ideal CAD model, in addition to the characterisation of residual porosity. The results show that optimal combinations of LT, DAR and DR produce high density parts with repeatable geometric properties. In addition, a quantitative analytical model was developed to optimise arbitrary parameter sets. This comprehensive investigation provides important insights into the APF process and increases its potential for wider industrial applications.

Keywords: Additive manufacturing | Arburg Plastic Freeforming (APF) | Geometric accuracy | Process optimisation | Residual porosity

Abstract: Purpose: This study aims to examine the efficacy of 3D printing polymers to realistically mimic the fossa ovalis (FO) – a cardiac structure that is positioned in the interatrial septum – for simulating transseptal puncture (TP) procedures. Design/methodology/approach: Specimen of different materials and thicknesses were prepared and tested simulating the puncturing of the FO using a 12F ID/14F OD TP catheter. Force and tenting length results were compared with literature references. Scanning electron microscope images of the specimen were acquired to observe the perforated region as well as the structure of the specimen in the unaffected area. Findings: Significant changes in the properties of interest were registered for the same material on specimens tested at different moments after fabrication. Suturable vessel wall polyjet material offers the best characteristics to replicate FO anatomy and mimic its behavior to puncturing. Originality/value: The originality of the work lies in the test of different commercial materials. Similar works are already present in literature but specifically designed materials are used. Demonstrating that off-the-shelf materials could be viable for FO specimens would simplify the design of realistic TP simulators in the future.

Keywords: Additive manufacturing | Advanced manufacturing technologies | Fossa ovalis | Material testing | Mechanical properties of materials | Simulation training | Training devices | Transseptal puncture

Abstract: This article presents a methodology for the design and production of custom prostheses for complex surgical interventions on long bones due to oncological surgical treatment. This type of intervention considers the complete or partial removal of bone tissue that might be affected by bone tumors. In this scenario it is important to limit the loss of functionality of the patients’ joints. Accordingly, it is important to salvage, whenever possible, the original articulation surfaces of the joints; nevertheless, a complete evaluation of the tumor extension and of the state of bone tissue might be difficult to be performed in the preparation phase. The article presents an approach for geometrical modelling of a modular prosthesis for long bones, that leaves the surgeon free to tailor the resection according to their feedback in the operating theatre. Specifically, the devised methodology allows to salvage part of the original bone by switching modules of the prosthesis. The dissertation is tackled from a technical perspective, taking into account the constraints and key features that need to be considered in the design and production of a long bone prosthesis via additive manufacturing technologies. The methodology is presented with reference to a complex custom prosthesis design that was carried out with the support of T3Ddy’s - Personalized pediatrics by inTegrating 3D aDvanced technologies research laboratory.

Keywords: Additive Manufacturing | Custom prosthesis | Design for Additive Manufacturing

Abstract: Soft Pneumatic Actuators (SPAs) have a simple structure of inner chambers that can be deformed to generate force when pressurized. Additive Manufacturing (AM) has been used to enhance SPAs by leveraging design freedom and customization for specific tasks. This study aims to develop a Finite Element Method (FEM) model to simulate a generic 3D-printed bellow SPA performing planar bending motion under pressure. The model, which can be used with different SPA design parameters, evaluates properties such as bending angle and exerted forces. The performance of a bellow SPA is influenced by factors such as its main dimensions, material, operating pressure, and chamber shape. This study considered three main contributors to bending behavior: wall chamber thickness, the number of bellow segments, and operating pressure. Various configurations were 3D-printed in Thermoplastic Polyurethane (TPU) and tested using a physical rig. FEM analyses were conducted within Ansys 2019 using static structural analysis. The second-order Ogden model was chosen for the hyper-elastic material according to reference [1]. Material parameters were identified for limited configurations through an optimization process that minimized the bending angle error. Other actuator configurations were simulated using various sets of parameters and compared with physical test results. The results showed a valid approximation across different actuator configurations. This study has developed an effective methodology to simulate the behavior of a generic 3D-printed TPU bellow SPA with a satisfactory level of approximation. © 2024, Scipedia S.L.

Keywords: 3D printing | Modeling | Pneumatic Actuator | Soft Actuator | Soft Material

Abstract: This work aims at the development of a streamlined and robust CAD procedure to design load-bearing implants. The methodology used to reach this result is explained in the paper: 3D digital anatomy reconstruction of defective structures of the patient is performed with the help of a statistical shape model; subsequently, a CAD modelling tool based on implicit modelling (i.e., nTopology) is used to implement a repeatable semi-automatic procedure that can be performed by a competent user with little effort and limited manual operations. Once that the main shape of the implant is defined, lattice geometries are generated to improve mechanical properties of the implant. The procedure requires as inputs the reconstructed anatomy of the patient and a series of clinical indications on the type of implant that needs to be designed. The paper discusses the development of the whole procedure; achieved results, which include the application of the whole framework on multiple case studies, are presented. The procedure allows the design of a whole implant in 20 minutes circa.

Keywords: CAD Design Automation | Custom Implant; Additive Manufacturing | Implicit Modelling | nTopology

Abstract: Additive Manufacturing has enabled the design of complex components in several technical fields. Considering turbomachinery components, additive manufacturing has unlocked the achievement of significant performances for dynamic rotoring components. The application of topology optimization methods is one of the main factors accelerating the technological development of this sector. This paper presents a procedure for the optimization of static turbomachinery components. The framework proposed compares the results obtained by introducing a lattice structure and a solid optimized shape. The procedure is presented with reference to a specific case study. To validate the proposed framework, the complete re-design of a thrust collar of a major Italian-based Oil&Gas company is carried out, demonstrating that the re-thinking of the component in terms of Topology Optimization is a straightforward approach to increase the overall performance of the produced part

Keywords: dynamic optimization | thrust washer | Topology optimization | turbomachinery

Abstract: Background: The right comprehension of ischemic stroke pathogenesis guarantees the best prevention therapy. The term “patent foramen ovale (PFO) related stroke” has been proposed for those events where PFO is supposed to be pathogenetic, but their definition is challenging. A multidisciplinary evaluation in a "Heart & Brain" team (HBteam) including stroke neurologists and interventional cardiologists was therefore highly recommended in the recent guidelines of secondary stroke prevention. Objective: We aimed at describing the organization of the HBteam of Careggi-University-Hospital of Florence (Italy), and the results of the first seven years of activity. Methods: In 2016 Interventional Cardiologists and Stroke Neurologists set up an outpatient clinic for the joined evaluation of patients with PFO and other cardio/neurological conditions. A specific diagnostic-therapeutic hospital plan was produced for PFO patients. Patient empowerment was guaranteed by a hospital explicative webpage, a booklet regarding risks/benefits of PFO closure and a 3D heartmodel to simulate the intervention. Data were collected in a dedicated registry. Results: We evaluated 594 patients for PFO, 40 for left atrial appendage closure and 38 for other conditions. In 20% of PFO-patients, HBteam diagnosis was discordant from that of referring physicians, 14% were stroke misdiagnoses. We advised against closure in 53% of patients. At follow-up 94% of closed patients had no/minimum residual shunt; 3 patients had a cerebral ischemic event. Conclusions: A dedicated HBteam represents a unique opportunity to share decisions with patients after a thorough empowerment process. The joining of cardioneurological skills allows a better classification of PFO-patients, reducing futile interventions.

Keywords: Closure | Heart and brain team | Ischemic stroke | Multidisciplinary | Patent foramen ovale | PFO

Abstract: Purpose: Left atrial appendage occlusion (LAAO) is a structural interventional cardiology procedure that offers several possibilities for the application of additive manufacturing technologies. The literature shows a growing interest in the use of 3D-printed models for LAAO procedure planning and occlusion device choice. This study aims to describe a full workflow to create a 3D-printed LAA model for LAAO procedure planning. Design/methodology/approach: The workflow starts with the patient’s computed tomography diagnostic image selection. Segmentation in a commercial software provides initial geometrical models in standard tessellation language (STL) format that are then preprocessed for print in dedicated software. Models are printed using a commercial stereolithography machine and postprocessing is performed. Findings: Models produced with the described workflow have been used at the Careggi Hospital of Florence as LAAO auxiliary planning tool in 10 cases of interest, demonstrating a good correlation with state-of-the-art software for device selection and improving the surgeon’s understanding of patient anatomy and device positioning. Originality/value: 3D-printed models for the LAAO planning are already described in the literature. The novelty of the article lies in the detailed description of a robust workflow for the creation of these models. The robustness of the method is demonstrated by the coherent results obtained for the 10 different cases studied.

Keywords: 3D Printing | Additive manufacturing | Heart model | Left atrial appendage occlusion | Left atrium | Stereolithography | Structural heart surgery | Surgical planning

Abstract: By progressively embracing the general principles of integrated, parametric, interdisciplinary design that considers the manufacturing elements of the imagined product, the modern aesthetic designer is called upon to broaden their knowledge and abilities. Especially when there is a need to produce complex shapes, when cost-effective, there are also numerous 3D printing technologies available today, to be used both in the conceptual phase (prototyping) and for actual production. The present paper aims to propose a discussion on the role of product engineering modelling in aesthetic design education. The progress of new 3D parametric modelling tools available to aesthetic designers is discussed, with a focus on the most cutting-edge features that have been released recently. The importance of parametric design education in general and the positive effects its application can have in the design process will also be discussed.

Keywords: aesthetic design | CAD | generative design | parametric modelling | product engineering | topology optimisation

Abstract: This paper presents the results of the design of noise reduction measures for the Florence “Sirio” Tram. This activity was performed in the framework of the Life “SNEAK” project (“Optimized surfaces against noise and vibrations produced by tramway track and road traffic”), LIFE20 ENV/IT/000181. Specifically, bogie skirts - i.e. noise barriers positioned on board of the vehicle, directly connected with the tram bogie - were designed and optimized to mitigate noise emissions from the wheel area. A test campaign was carried out to acquire sound profiles describing the emissions of interest of the Sirio tram. Repeated measurements were performed to measure: i) rolling noise emitted by the bogie while the tram is moving along a straight line at maximum cruising speed (50 km/h); ii) braking noise in a full stop; iii) squeal noise, which happens when the tram passes through a tight curve in absence of lubricant. A customized solution, which implements a sound-insulating and sound-absorbing panel placed in front of the wheel, was designed to replace the existing set of wheel covering panels. Such a device includes an extended barrier towards the ground to limit the noise emission area to a minimum. The preliminary results obtained with the proposed solution, which was tested in a simplified scenario, are discussed in the paper.

Keywords: noise mitigation | squeal noise | tram

Abstract: Within the literature concerning modern machine learning techniques applied to the medical field, there is a growing interest in the application of these technologies to the nephrological area, espe-cially regarding the study of renal pathologies, because they are very common and widespread in our society, afflicting a high percentage of the population and leading to various complications, up to death in some cases. For these reasons, the authors have considered it appropriate to collect, using one of the major bibliographic databases available, and analyze the studies carried out until February 2022 on the use of machine learning techniques in the nephrological field, grouping them according to the addressed pathologies: renal masses, acute kidney injury, chronic kidney disease, kidney stone, glomerular disease, kidney transplant, and others less widespread. Of a total of 224 studies, 59 were analyzed according to inclusion and exclusion criteria in this review, considering the method used and the type of data availa-ble. Based on the study conducted, it is possible to see a growing trend and interest in the use of machine learning applications in nephrology, becoming an additional tool for physicians, which can enable them to make more accurate and faster diagnoses, although there remains a major limitation given the diffi-culty in creating public databases that can be used by the scientific community to corroborate and even-tually make a positive contribution in this area.

Keywords: artificial intelligence | deep learning | machine learning | renal pathology

Abstract: The present paper presents the development of a novel procedure for the modeling of Surgical Cutting Guides (SCGs) exploiting an implicit modeling approach. As discussed in the text, this approach allows for a streamlined and efficient design of this type of medical device. A procedural approach based on the application of a series of a priori-known implicit modeling function allows the generation of personalized surgical guides starting from the i) patient’s anatomy and ii) clinical decisions made by the medical staff. The CAD procedure is detailed in the text; achieved results are discussed and compared with a traditional CAD modeling approach on three case studies.

Keywords: CAD | Implicit Modelling | Patient-Specific Instrument | Personalized Medical Device

Abstract: Dealing with the design of personalized medical devices, mass production is not an option that can be hypothesized. Indeed, a cumbersome production process must be considered in such cases, mainly to account for a delicate design phase that needs to take into consideration, as input, an anatomy that vary each time. This article discusses the development of a statistical tool able to support the design of patient-specific devices. By expanding the classical formulation of the Statistical Shape Model (SSM) with the introduction of multiple levels of information within the same model, the authors have experimented with the concept of an “enhanced SSM”. While the traditional SSM only provides information on the variations that a class of shapes can manifest, the eSSM may include more levels of information. The article discusses two possible mathematical formulations of such statistical tool. Its application to the design of custom-made pelvic implants is discussed. Such application scenario is described starting from the generation of the eSSM for the pelvis. The features of interest considered in this paper are the centers of the acetabular regions of the pelvis, the segmentation of the anatomy in a series of semantical regions that must be considered when developing a load-bearing implant. Finally, the conclusions of this research are drawn and discussed together with possible future development of eSSMs.

Keywords: Biomedical engineering | Custom implant design | Human modelling | Pelvis | SSM | Statistical shape analysis

Abstract: The realization of medical devices to assist the surgeon in autologous auricular reconstruction (personalized surgical guides) requires the use of depth maps images obtained from 3D scans of the patient's profile. In order to make the process of ear geometry acquisition and depth map realization faster, more comfortable for the patient and easily accessible by hospital staff, this work proposes a system able to create depth maps from a single RGB image. The proposed approach involves the integration of tools based on convolutional neural networks to build a modular system capable of isolating the ear from the profile, creating the corresponding depth map, and refining it to correct inaccuracies. The system was trained and tested using a database of human profile images and corresponding depth maps made available by the University of Notre Dame. To evaluate the result in this preliminary study, standard metrics such as mean square error and structural similarity were used, yielding results suitable for the targeted application.

Keywords: 3D vision | CNN | Depth map estimation | Ear reconstruction

Abstract: The present paper describes a procedure for the development and production of a physical model for surgical planning of a Left Ventricular Aneurysm. The method is based on the general approach provided in Otton et al. (2017) and was customized to seek a reliable and fast procedure for the production of a specific type of cardiac model – i.e. chambers of the left side of the heart. The paper covers all the steps: processing of the data, segmentation, modelling and 3D printing; details are provided for all the phases, in order to allow the reproduction of the achieved results. The procedure relies on Computed Tomography - CT imaging as data source for the identification and modelling of the anatomy. Materialise Mimics was used as segmentation software to process the CT data. While its usefulness for the surgical needs was verified on a single clinical case (provided by the Careggi Hospital of Florence, Italy), the modelling procedure was tested twice, to produce a physical replica both ex-ante and ex-post surgical intervention. • The tools used for segmentation and generation of the printable model were customized to reduce modelling time for the specific type of desired model. • Detailed information on the use of modeling tools, not available in the literature, will be provided. • The procedure allows fabrication of a physical model representing the heart chambers in a short time.

Keywords: 3D printing | Left Ventricular Aneurysm | Method for the production of an anatomical replica of a human heart for surgical planning | Surgical planning

Abstract: A 59-year-old woman was admitted to the emergency department for heart failure (HF), New York Heart Association (NYHA) IV, showing an anterior, evolved myocardial infarction (MI) with a wide apical left ventricular aneurysm (LVA), ejection fraction (EF) 24%, and global longitudinal strain (GLS) −5. 5% by echo. Cardiac magnetic resonance imaging (MRI) confirmed an apical LVA without thrombus, EF 20%, and a transmural delayed enhancement in the myocardium wall. Coronarography showed a three-vessel disease with occluded proximal left anterior descending (LAD) and proximal right coronary artery (RCA). Based on the cardiac CT scan, we decided to generate a three-dimensional (3D) print model of the heart, for better prediction of residual LV volumes. After LVA surgery plus complete functional revascularization, an optimal agreement was found between predicted and surgical residual LV end-diastolic (24.7 vs. 31.8 ml/m2) and end-systolic (54.1 vs. 69.4 ml/m2) volumes, with an improvement of NYHA class, from IV to I. The patient was discharged uneventfully and at 6- and 12-month follow-up, the NYHA class, and LV volumes were found unchanged. This is a second report describing the use of the 3D print model for the preoperative planning of surgical management of LVA; the first report was described by Jacobs et al. among three patients, one with a malignant tumor and the remaining two patients with LVA. This article focused on the use of the 3D print model to optimize surgical planning and individualize treatment of LVA associated with complete functional revascularization, leading to complete recovery of LV function with a favorable outcome.

Keywords: 3D printing model | CAD | heart failure | left ventricular aneurysm | surgical ventricular restoration

Abstract: The LIFE SNEAK project, started in September 2021, aims at the reduction of noise in densely populated urban areas where noise and vibrations produced by the tram overlap with noise produced by road traffic. Applicative measures will be designed and tested in a pilot case of the city of Florence, such as low-noise and vibration surfaces, with life cycle costs comparable to those of traditional surfaces, and measures to reduce tram noise aiming to obtain substantial reductions in noise and annoyance. Referring to tram noise, in the first phase of the project, specific attention has been dedicated to the state-of-the-art analysis concerning possible measures to perform noise reduction with specific attention to noise due to wheel-rail contact and “squeal noise” phenomena that mainly occur in urban environments close to curves with small radius. In this paper, the results of the state-of-the-art analysis are presented with particular attention to the use of sound-absorbing panels to be applied on the tram (bogie skirts).

Keywords: Acoustic noise | Acoustic wave absorption | Life cycle | Noise pollution | Sound insulating materials | Trolley cars

Abstract: RGB-D cameras are employed in several research fields and application scenarios. Choosing the most appropriate sensor has been made more difficult by the increasing offer of available products. Due to the novelty of RGB-D technologies, there was a lack of tools to measure and compare performances of this type of sensor from a metrological perspective. The recent ISO 10360-13:2021 represents the most advanced international standard regulating metrological characterization of coordinate measuring systems. Part 13, specifically, considers 3D optical sensors. This paper applies the methodology of ISO 10360-13 for the characterization and comparison of three RGB-D cameras produced by Intel® RealSense™ (D415, D455, L515) in the close range (100–1500 mm). ISO 10360-13 procedures, which focus on metrological performances, are integrated with additional tests to evaluate systematic errors (acquisition of flat objects, 3D reconstruction of objects). The present paper proposes an off-the-shelf comparison which considers the performance of the sensors throughout their acquisition volume. Results have exposed the strengths and weaknesses of each device. The D415 device showed better reconstruction quality on tests strictly related to the short range. The L515 device performed better on systematic depth errors; finally, the D455 device achieved better results on tests related to the standard.

Keywords: Active stereo | Depth camera | Device characterization | ISO 10360-13 | LiDAR | Performance comparison | RealSense D415 | RealSense D455 | RealSense L515 | Reverse engineering

Abstract: Robotic devices are being employed in more and more sectors to enhance, streamline, and augment the outcomes of a wide variety of human activities. Wearable robots arise indeed as of-vital-importance tools for telerehabilitation or home assistance targeting people affected by motor disabilities. In particular, the field of “Robotics for Medicine and Healthcare” is attracting growing interest. The development of such devices is a primarily addressed topic since the increasing number of people in need of rehabilitation or assistive therapies (due to population aging) growingly weighs on the healthcare systems of the nation. Besides, the necessity to move to clinics represents an additional logistic burden for patients and their families. Among the various body parts, the hand is specially investigated since it most ensures the independence of an individual, and thus, the restoration of its dexterity is considered a high priority. In this study, the authors present the development of a fully wearable, portable, and tailor-made hand exoskeleton designed for both home assistance and telerehabilitation. Its purpose is either to assist patients during activities of daily living by running a real-time intention detection algorithm or to be used for remotely supervised or unsupervised rehabilitation sessions by performing exercises preset by therapists. Throughout the mechatronic design process, special attention has been paid to the complete wearability and comfort of the system to produce a user-friendly device capable of assisting people in their daily life or enabling recorded home rehabilitation sessions allowing the therapist to monitor the state evolution of the patient. Such a hand exoskeleton system has been designed, manufactured, and preliminarily tested on a subject affected by spinal muscular atrophy, and some results are reported at the end of the article.

Keywords: hand exoskeleton | home assistance | mechatronics design | robotics | telerehabilitation | wearable robot

Abstract: This paper considers the fitting of a CAD template model to tessellated data as strategy to implement a reverse engineering process that aims at the reconstruction of a parametric associative CAD model. The reconstruction methodology, called Template-Based CAD Reconstruction (TCRT), has been presented and fully discussed in a previous paper Buonamici et al. (J Comput Des Eng 5:145–159, 2018). The present paper focuses on the study of a fast and robust strategy to perform the fitting of the Template CAD Model to reference data. The study explores how different optimization strategies and evaluation metrics can affect a parametric CAD-fitting methodology. Two different optimization algorithms (PSO and GA) and three formulations of the objective function are tested to find the most effective combination. Reconstruction test cases are presented and discussed in the text.

Keywords: CAD reconstruction | CAD template | Fitting | Genetic Algorithm | Particle Swarm Optimization | Reverse engineering

Abstract: Cranioplasty is a procedure performed to repair defects in the human skull bone by surgically reconstructing the shape and function of the cranium. Several complications, both intraoperative and postoperative, can affect the procedure’s outcome (e.g., inaccuracies of the reconstructed shape, infections, ulcer, necrosis). Although the design of additive manufactured implants in a preoperative stage has improved the general quality of cranioplasties, potential complications remain significant, especially in the presence of critical skin tissue conditions. In this paper, an innovative procedure to improve the chances of a positive outcome when facing critical conditions in a cranioplasty is described. The proposed approach relies on a structured planning phase articulated in a series of digital analyses and physical simulations performed on personalized medical devices that guide the surgeon in defining surgical cuts and designing the implant. The ultimate goal is to improve the chances of a positive outcome and a fast recovery for the patient. The procedure, described in extenso in the paper, was positively tested on a cranioplasty case study, which presented high risk factors.

Keywords: Additive manufacturing | Cranioplasty | Patient-specific implant | Skull reconstruction

Abstract: The objective of this study is to establish a new methodology for the metrological characterization of interactive multi-camera systems. In the case of 3D system highly adapted to specific needs the accuracy evaluation cannot be performed using standard state-of-the-art techniques. To this end, the metrological characterization techniques used in the literature were investigated in order to define a new methodology that can be adjusted to each device by making the appropriate modifications. The proposed strategy is adopted for the metrological characterization of a new interactive multi-camera system for the acquisition of the arm.

Keywords: Accuracy assessment | Device characterization | Multi-camera system | Optical device | VDI/VDE normative

Abstract: The article discusses the design of an acquisition system for the 3D surface of human arms. The system is composed by a 3D optical scanner implementing stereoscopic depth sensors and by an acquisition software responsible for the processing of the raw data. The 3D data acquired by the scanner is used as starting point for the manufacturing of custom-made 3D printed casts. Specifically, the article discusses the choices made in the development of an improved version of an existing system presented in [1] and presents the results achieved by the devised system.

Keywords: 3D printing | 3D scanning | Arm scanner | Body scanner | Orthoses

Abstract: Robotics for Medicine and Healthcare is undoubtedly an important emerging sector of the newborn third millennium. There are many aspects in which this branch of robotics already operates; in this article, the focus will be on the so-called “Robotic assistive technology”. In particular, a novel electromechanical design for an assistive Hand Exoskeleton System is presented here. Since freedom of movement plays a crucial role in making actually usable an assistive device, the main point of innovation of the proposed solution lies in the complete wearability of the resulting system: including mechanics, control electronics, and power supply. From the combination of the authors’ previous experience with the improvements presented in this article comes a fully standalone tailor-made assistive device.

Abstract: The availability of advanced tools able to model complex geometries along with the relaxing of the constraints related to the manufacturing technologies are heavily transforming the design approach in many fields, including healthcare. The focus of this paper is on the optimization of porous lightweight cellular geometries in the orthopedic implants design: lattice structures have proven to fulfill the biological, mechanical, and technological constraints required in designing load bearing devices. The aim is to collect the information provided by the related literature to describe the effects induced by the selection of parameters designing lattice gyroid structures for orthopedic implants.

Keywords: custom metal implant | design for additive manufacturing | gyroid | metallic lattice structures | triply periodic minimal surface

Abstract: Pectus Arcuatum (PA) is a congenital chest wall deformity which produces a superior manubrial and sternal protrusion, particularly at the sternal angle. PA surgical correction to reduce the angle of the sternum always includes the removal of bone portion by means of horizontal sternal osteotomies, resection of deformed rib cartilage and finally stabilization of the anterior thoracic wall. Within this process an incorrect assessment of the sternotomy angle during the procedure may lead to the need for bone or cartilage grafts to fill the left voids. This problem has been addressed with a patient-specific cutting template, realized with Reverse Engineering and Additive Manufacturing techniques, which proved to be a key element to simplify the procedure and avoid the occurrence of this type of complications. In this work is presented and validated a procedure that, through common CAD operations, realizes in a completely automatic way the CAD model of the custom cutting template, so as to make non-expert users independent in the realization of the medical device.

Abstract: Designing an acquisition system for 2D or 3D information, based on the integration of data provided by different sensors is a task that requires a labor-intensive initial design phase. Indeed, the definition of the architecture of such acquisition systems needs to start from the identification of the position and orientation of the sensors observing the scene. Their placement is carefully studied to enhance the efficacy of the system. This often coincides with the need to maximize the surfaces observed by the sensors or some other metric. An automatic optimization procedure based on the Particle Swarm Optimization (PSO) algorithm, to seek the most convenient setting of multiple optical sensors observing a 3D scene, is proposed. The procedure has been developed to provide a fast and efficient tool for 2D and 3D data acquisition. Three different objective functions of general validity, to be used in future applications, are proposed and described in the text. Various filters are introduced to reduce computational times of the whole procedure. The method is capable of handling occlusions from undesired obstacle in the scene. Finally, the entire method is discussed with reference to 1) the development of a body scanner for the arm-wrist-hand district and 2) the acquisition of an internal environment as case studies.

Keywords: 3D scanning | Body scanner | Computer graphics | Optical sensors | PSO | Sensor placement | Visibility analysis

Abstract: In recent years, breakthroughs in the fields of reverse engineering and additive manufacturing techniques have led to the development of innovative solutions for personalized medicine. 3D technologies are quickly becoming a new treatment concept that hinges on the ability to shape patient-specific devices.Among the wide spectrum of medical applications, the orthopaedic sector is experiencing the most benefits. Several studies proposed modelling procedures for patient-specific 3D-printed casts for wrist orthoses, for example. Unfortunately, the proposed approaches are not ready to be used directly in clinical practice since the design of these devices requires significant interaction among medical staff, reverse engineering experts, additive manufacturing specialists and CAD designers. This paper proposes a new practical methodology to produce 3D printable casts for wrist immobilization with the aim of overcoming these drawbacks. In particular, the idea is to realize an exhaustive system that can be used within a paediatric environment. It should provide both a fast and accurate dedicated scanning of the hand-wrist-arm district, along with a series of easy-to-use semi-automatic tools for the modelling of the medical device. The system was designed to be used directly by the clinical staff after a brief training. It was tested on a set of five case studies with the aim of proving its general reliability and identifying possible major flaws. Casts obtained using the proposed system were manufactured using a commercial 3D printer, and the device’s compliance with medical requirements was tested. Results showed that the designed casts were correctly generated by the medical staff without the need of involving engineers. Moreover, positive feedback was provided by the users involved in the experiment.

Keywords: CAD | Cast modelling | Orthosis modelling | Personalized medicine | Reverse engineering

Abstract: The autologous ear reconstruction surgery, i.e. the reconstruction of the missing ear anatomy with autologous cartilage tissue in case of partial or complete absence of the auricular region, can be extremely complicated due to the unique shape and size of this anatomical region. Operations of sculpting and carving of the costal cartilage in order to realize the ear reproduction require a high degree of manual expertise and experience from the surgeon. The development of surgical aids that can provide the physician with guidelines during the reconstruction is being studied in the literature. However, state-of-the-art techniques do not represent the optimal solution and only partially help in the reconstruction process. They are based on two-or three-dimensional templates of the target anatomy, providing visual support, yet not helping in the actual reconstruction phase, or, in some cases, by providing active aid but not simplifying the procedure sufficiently. In this context, the option of creating custom cutting guides that could actively assist the surgeon both in the pre-operative planning phase and during the surgery was considered. The proposed approach involves the use of surgical guides adopted for the cutting and reconstruction of the individual anatomical elements involved. Through an iterative process carried out in collaboration with the surgeon the characteristics of the surgical guides have been defined. Subsequently, a method that can be applied systematically to model the cutting guides, ready to be printed with additive production techniques was defined. The procedure was designed with a view to a future semi-automatization of the entire process that could make the physician autonomous in the realization of the patient-specific guides.

Keywords: 3D Ear Templates | Autologous Ear Reconstruction | CAD modelling | Personalized Medicine | Reverse Engineering

Abstract: Generative design tools have recently become an interesting solution to tackle design problems in several technical fields. This article takes into consideration the specific field of mechanical design and aims at describing available generative design solutions capable of dealing with structural optimization problems. The study provides a practical description on the workflow and performances of a specific software system implementing a generative approach for the generation of a set of alternative solutions for a static structural design problem. The software analyzed is Autodesk’s Generative Design, hosted in Fusion 360. The article discusses the functioning of the software and its performances; an enhanced focus on the features oriented to the generation of manufacturable shapes is provided in the text. In order to provide a practical and effective procedure, a literature case study was selected to test the software.

Keywords: Biomimetic Design | CAD | Generative Design | Structural Optimization | Topology Optimization

Abstract: Computer Numerical Control (CNC) milling is still today the elective process for the production of single-piece impellers, as it can reliably produce complex geometries, removing the need for additional manufacturing processes. Nevertheless, Additive Manufacturing is winning more and more ground due to its ability to make components of any geometry that cannot be produced using subtractive techniques. As a result, the use of this technology can eventually be seen as the key to develop high-performance rotor components. In this scenario, the design of 3D impellers does not make an exception. Accordingly, the present paper proposes a general framework for engineered re-design and manufacture of 3D impellers installed on centrifugal compressors by exploiting Topology Optimization and Additive Manufacturing's potential. The procedure investigates also the rotoric component's best configuration for both static and dynamic behavior. Finally, the topology-optimized component is produced with AM through the use of suitable materials that can ensure efficient mechanical efficiency to prove the manufacturability of the entire procedure. To validate the proposed framework, the complete re-design of a 3D impeller of a major Italian-based Oil Gas company is carried out, demonstrating that the re-thinking of the component in terms of Topology Optimization is a straightforward approach to increase the overall performance of the produced rotoric part.

Keywords: 3D impellers | additive manufacturing | design | topology optimization | turbomachinery

Abstract: Computer Aided reconstruction of mechanical parts nowadays heavily relies on dedicated RE software systems and highly skilled users to be carried out effectively. This paper investigates this scenario in order to identify most limiting factors in the current framework. With this respect, several considerations of general validity are drawn while presenting the problem from a theoretical perspective. A significant test case reconstruction, discussed in depth in the manuscript, is used to provide a practical point of view on real applications and help the reader acquire a hands-on comprehension of the current situation.

Keywords: CAD | CAD reconstruction | Reverse engineering

Abstract: Bone tumor resections have to be carefully planned in order to avoid intralesional cuts and thus lower the recurrence rate. Until the present-day bone resections have been performed freehand, using anatomical landmarks as reference points to retrieve planned resection planes over the very patient. Such method is highly prone to failure to the detriment of the patient’s health, in fact survival rate for osteosarcomas is very low, ranging between 20% and 47%. The clinical outcome is highly dependent on the resections’ accuracy; several emerging techniques proved to dramatically increase cutting accuracy, as well as survival rate, in particular Patient Specific Instruments (PSIs) and custom 3D printed metal prosthesis. The main limitation to a massive spread of this method is the large manufacturing time due to a lack of communication between surgeons and engineers about the surgical approach and the design constraints. This paper aims to compare several general-purpose low-cost software and to provide surgeons with an effective and easy to use platform to visually share information in a natural manner with engineers thus providing as many design constraints as possible, speed up the design process and avoid unfeasible results. Two surgeons from Azienda Ospedaliera Universitaria Careggi tested and evaluated a series of software. From this preliminary investigation Forger, a digital sculpting and texture painting application for iOS, resulted as the most user friendly and intuitive application among the test group.

Keywords: Computer aided surgery | Concurrent design | Digital surgical planning | Human computer interaction

Abstract: The introduction of the vacuum bell (VB) for the conservative treatment of Pectus Excavatum (PE) has led to a new non-invasive alternative to thoracic surgery. The VB works by elevating the chest as long as a negative differential pressure is internally assured. In recent years studies have been conducted to validate this type of treatment and to outline its correct use; results show a short-term PE improvement when the device is worn for a minimum of 30 min (twice a day) up to a maximum of several hours a day for 12–15 months. Although the worldwide diffusion of VB devices increases year after year, its ability to lift the chest during treatment with respect to the applied pressure has begun to be evaluated only recently. In this paper, a new instrument for measuring chest elevation during treatment is presented and validated. The proposed system consists of two measurement devices: a commercial instrument for the detection of the negative pressure inside the VB, and a specifically developed optical system for the detection of chest movement. The effectiveness of the proposed system, tested on five paediatric patients, paves the way to the objective definition of an optimised patient specific VB scheme of use.

Keywords: Image processing | Optical measurement | Pectus Excavatum | Vacuum bell

Abstract: The present paper presents the study of a semi-automatic CAD technique for the generation of ventilation holes on ABS AM-manufactured arm orthoses. A lighter device, good air and water transpiration and an increased patient’s comfort are the main advantages achievable by introducing openings on plastic casts. The proposed procedure relies on the adaptation of a reference pattern of holes, obtained integrating both structural and functional aspects, to each patient’s cast. The adaptation procedure maps the original pattern, respecting its proportions, on each target orthosis, thanks to a set of reference points automatically extracted. The generation of holes is performed relying on an advanced CAD environment (i.e. Siemens NX), where a series of CAD modeling operations, based on the data extracted by the mapping algorithm, have been studied and tested. The whole procedure has been tested on 5 orthoses to validate its efficacy.

Keywords: Cad | Cast modeling | Orthosis modeling | Personalized medicine

Abstract: To date, standard methods for assessing the severity of chest wall deformities are mostly linked to X-ray and CT scans. However, the use of radiations limits their use when there is a need to monitor the development of the pathology over time. This is particularly important when dealing with patients suffering from Pectus Carinatum, whose treatment mainly requires the use of corrective braces and a systematic supervision. In recent years, the assessment of severity of chest deformities by means of radiation-free devices became increasingly popular but not yet adopted as standard clinical practice. The present study aims to define an objective measure by defining a severity index (named External Pectus Carinatum Index) used to monitor the course of the disease during treatment. Computed on the optical acquisition of the patients’ chest by means of an appositely devised, fast and easy-to-use, body scanner, the proposed index has been validated on a sample composed of a control group and a group of Pectus Carinatum patients. The index proved to be reliable and accurate in the characterization of the pathology, enabling the definition of a threshold that allows to distinguish the cases of patients with PC from those of healthy subjects. [Figure not available: see fulltext.]

Keywords: Index | Optical imaging | Pectus Carinatum | Severity assessment | Three-dimensional

Abstract: The present paper proposes a methodology to design and manufacture optimized turbomachinery components by leveraging the potential of Topology Optimization (TO) and Additive Manufacturing (AM). The method envisages the use of TO to define the best configuration of the rotoric components in terms of both static and dynamic behavior with a resultant reduction of overall weight. Eventually, the topology-optimized component is manufactured by using appropriate materials that can guarantee valid mechanical performances. The proposed strategy has been applied to a 2D impeller used for centrifugal compressors to prove the effectiveness of a TO+AM-based approach. Although this approach has never been extensively used before to centrifugal compressors and expanders, its application on rotor and stator components might unlock several benefits: Tuning the natural frequencies, a reduction in the stress level, and a lighter weight of the rotating part. These objectives can be reached alone or in combination, performing a single analysis or a multiple analyses optimization. Finally, the introduction of AM technologies as standard manufacturing resources could bring sensible benefits with respect to the time to production and availability of components. Such aspects are essential in the Oil and Gas context, when dealing with new projects but also for service operations.

Abstract: Bamboo is one of the longest-used organic raw materials in the tropics for a large number of different purposes in the daily lives of human beings. Because of its excellent physical-mechanical properties, in many parts of the world it is widely used as a structural material, especially for the construction of scaffolding and the construction of buildings. The bamboo can be modelled as a composite material, consisting of a of a parenchyma cells matrix, similar to a foam, reinforced by bundles of fibers associated with vessels. The present work aimed to explore the possibility to design a 3D printed biomimetic composite material able of keeping advantages from the bamboo morphological structure. Samples made of PVA, ABS and PVA + ABS were manufactured using Fused Deposition Modelling and tested under compression and bending conditions. The behavior under compression has shown to depend mainly on the material used while in bending the structure has shown important effects leading the sample made of PVA + ABS to have the same performances of much expensive pure ABS.

Keywords: Additive manufacturing | Bamboo | Structure optimization

Abstract: Within the T-VedO project, financed by Tuscany Region, the Reverse Engineering and Virtual Prototyping Lab team of the Department of Industrial Engineering of Florence (Italy) developed a number of methods for the semiautomatic generation of digital 2.5D models starting from paintings. Once such models are prototyped, they can be used to enhance visually impaired people tactile experience of artworks. Such methods, combined into a systematic procedure, allow to solve most of the typical problems arising when dealing with artistic representation of a painted scene. The present paper presents both an overview of the proposed procedure, including most recent updates, and the results obtained for a selected number of artworks of the Florentine Renaissance.

Keywords: 2.5D models | 3D Reconstruction | CAD

Abstract: Reverse Engineering (RE) is a long-term goal of engineering and computer science; it aims at the reconstruction of CAD models from measured data by means of 3D mathematical surfaces and geometrical features representing the geometry of a physical part. In the last two decades, reviews and surveys have occasionally covered this topic, but a systematic dissertation of modeling methods from a mechanical engineering point of view is still missing. The purpose of this paper is to fill this gap; starting from a general description of the overall RE framework (acquisition, segmentation, classification, fitting), both an up-to-date survey and a categorization of available modeling techniques and tools working on 3D data are provided. The main aspects of various strategies are discussed as well, in order to highlight strengths and weaknesses characterizing different approaches. Moreover, an overview of commercial software for RE is presented, considering both dedicated solutions and packages supplied as add-on with ‘traditional’ CAD systems. Finally, possible improvements to be addressed by the research in the RE field are discussed, outlining potential future trends that are still to be investigated.

Keywords: 3D modeling | CAD reconstruction | constrained fitting | Reverse engineering | reverse engineering software

Abstract: Template-Based reverse engineering approaches represent a relatively poorly explored strategy in the field of CAD reconstruction from polygonal models. Inspired by recent works suggesting the possibility/opportunity of exploiting a parametric description (i.e. CAD template) of the object to be reconstructed in order to retrieve a meaningful digital representation, a novel reverse engineering approach for the reconstruction of CAD models starting from 3D mesh data is proposed. The reconstruction process is performed relying on a CAD template, whose feature tree and geometric constraints are defined according to the a priori information on the physical object. The CAD template is fitted upon the mesh data, optimizing its dimensional parameters and positioning/orientation by means of a particle swarm optimization algorithm. As a result, a parametric CAD model that perfectly fulfils the imposed geometric relations is produced and a feature tree, defining an associative modelling history, is available to the reverse engineer. The proposed implementation exploits a cooperation between a CAD software package (Siemens NX) and a numerical software environment (MATLAB). Five reconstruction tests, covering both synthetic and real-scanned mesh data, are presented and discussed in the manuscript; the results are finally compared with models generated by state of the art reverse engineering software and key aspects to be addressed in future work are hinted at.

Keywords: 3D mesh | CAD reconstruction | CAD template | Constrained fitting | Particle Swarm Optimization | Reverse engineering

Abstract: Several models of FDM machines, characterized by different architecture and hardware components, have flooded the market in the last 5 years. As a result, given the high sensitivity of FDM to the specific machine characteristics, the search for optimal printing parameters is a renown problem. This two-parts paper proposes an easy-to-follow and low-cost procedure for the characterization of any given FDM machine. The method allows the evaluation of the effects of a wide selection of FDM process parameters on the quality of 3D printed parts. The first part focused on the definition of a series of metrics to be measured on a series of test prints to evaluate the quality of the produced parts. The evaluation of seven quality parameters on a single print is made possible thanks to: i) a specifically designed specimen that is made available to the user and ii) a rigorous and repeatable measurement procedure, which are both discussed in the first part of the paper. This second part presents the characterization procedure, the statistical tools used in the experimentation (DOE tools and principles are adopted throughout the experimentation) and provides guidelines to be used for the characterization of any FDM machine. The whole procedure is tested on a desktop FDM machine to demonstrate obtainable results, proving the efficacy of the proposed methodology and highlight strengths and drawbacks of the approach.

Keywords: 3D printing | Additive manufacturing (AM) | Design of experiments (DOE) | Fused deposition modeling (FDM) | Process optimization

Abstract: Several models of FDM machines, characterized by different architecture and hardware components, have flooded the market in the last 5 years. As a result, given the high sensitivity of FDM to the specific machine characteristics, the search for optimal printing parameters is a renown problem. This two-parts paper proposes an easy-to-follow and low-cost procedure for the characterization of any given FDM machine. The method allows the evaluation of the effects of a wide selection of FDM process parameters on the quality of 3D printed parts. The first part focuses on the definition of a series of metrics to be measured on a series of test prints to evaluate the quality of the produced parts. Specifically, several effects are considered: dimensional accuracy, small details, overhang surfaces, ability of printing small holes/thin extrusions and overall quality of the prints. The evaluation of seven quality parameters on a single print is made possible thanks to: i) a specifically designed specimen that is made available to the user and ii) a rigorous and repeatable measurement procedure, which are both discussed in the first part of the paper. The second part presents the characterization procedure, the statistical tools used in the experimentation and provides guidelines to be used for the characterization of any FDM machine. The whole procedure is tested on a desktop FDM machine to demonstrate obtainable results.

Keywords: 3D Printing | Additive Manufacturing (AM) | Design of Experiments (DOE) | Fused Deposition Modeling (FDM) | Process Optimization

Abstract: Wrist injuries are one of the most common fractures, specifically around 25% of fractures among the pediatric population and up to 18% in the elderly age group are distal radius fractures. To date, the standard treatment entails the use of a tailor-made plaster of Paris cast. Although it is a simple and reliable treatment, it presents several disadvantages: its weight generally causes discomfort, it cannot be taken off without breaking it, it can cause skin rashes and prevents ventilation of the treated area. To overcome the limitations of the above mentioned treatment, 3D printed orthopaedic casts based on reverse engineering (RE) and additive manufacturing (AM) techniques have been proposed in literature. Despite these solutions prove to be a valid alternative to the standard treatment, the clinical use of AM-based devices is not trivial due to the need of expert CAD modelers to design the 3D model of the orthosis starting from the patient’s anatomy 3D acquisition. In this work, the authors identify a systematic procedure to create an orthosis model, compliant with medical guidelines, using common CAD tools. The systematic procedure, even still manually performed, envisages a set of tasks, grouped into five main blocks, that will be easy to be automatized in the future, thus eliminating the necessity of designing expertise to model the orthosis. The proposed procedure allows to design a device composed of two halves, to ease the application, locked through a zip tie-based mechanism. A preliminary ventilation pattern is proposed and tested with a FEM analysis to ensure structural resistance. The procedure has been tested on six case studies: all the orthoses models were correctly generated without major complications and positive user feedbacks were generally obtained throughout the tests.

Keywords: Cad | Cast modeling | Orthosis modelling | Personalized medicine | Reverse engineering

Abstract: The surgical process adopted to repair cranial defects using an implant, typically called Cranioplasty, has seen an abrupt increase in recent years due to the introduction of Reverse Engineering (RE) and Additive Manufacturing (AM) techniques. By adopting these techniques, CT/MRI data can be used to reconstruct, in a pre-operative stage, the 3D anatomy of the defective skull in order to design a patient-specific digital model of the prosthesis. The so-designed cranial plate can be then fabricated via AM, in a suitable metal alloy, and implanted. This allows for a perfect fit of the implant during the actual surgery, reducing the risks for the patient and increasing the efficacy of the treatment. This paper reviews existing approaches for the virtual reconstruction of defective skulls, and a basic classification, proposing four different classes of strategies (Mirroring, Surface Interpolation, Template-Based and Slice-based techniques) is provided. The findings of the study suggest that the reconstruction of skull defects is still an open problem, due to the complexities imposed by surface that needs to be retrieved (i.e. the human anatomy). All the presented approaches share weaknesses and limits, which are discussed in the article. Finally, possible directions to improve the existing techniques are briefly presented.

Keywords: Biomedical engineering | Cranioplasty | Reverse engineering | Skull reconstruction

Abstract: Reverse Engineering represents a long-term goal of computer science and engineering; it aims at the reconstruction of digital models from measured data by means of 3D mathematical surfaces and geometrical features representing the geometry of a physical part. In this paper, an overview of constrained fitting optimization methods specifically devised for the reconstruction of mechanical parts is proposed, highlighting the connections between the theoretical problem and some practical solutions. Furthermore, algorithmic procedures are provided in order to underline the main differences between the considered approaches. Critical aspects of constrained fitting and recent trends on Reverse Engineering are finally presented and discussed.

Keywords: CAD reconstruction | Constrained fitting | Optimization algorithms | Reverse engineering

Abstract: The participation of blind people (BP) in cultural life can be improved by enhancing methodologies and tools for facilitating the 3D reproduction of artworks and, at the same time, to facilitate their exploration. The creation of integrated systems including not only tactile media such as, for instance, sculptures or bas-reliefs but even a set of tools capable of providing the users with an experience cognitively comparable to the one originally envisioned by the artist, may undoubtedly enhance artworks exploration. The present work aims to design a conceptual system to aid BP in the tactile exploration of bas-reliefs. This conceptual system comprises both a hand-tracking system and an audio device, together with a number of methodologies, algorithms and information related to physical design. The designed layout, preliminarily tested to understand its potential and limits, proved to be a promising first attempt in enhancing the BP exploration experience.

Keywords: 3D reconstruction | Blind people | Hand-tracking system | Tactile bas-relief | Tactile exploration

Abstract: This paper presents a brief review of recent methods and tools available to designers to perform reverse engineering of CAD models starting from 3D scanned data (mesh/points). Initially, the basic RE framework, shared by the vast majority of techniques, is sketched out. Two main RE strategies are subsequently identified and discussed: automatic approaches and user-guided ones.

Keywords: CAD reconstruction | Constrained Fitting | Reverse Engineering

Abstract: Nowadays, the creation of methodologies and tools for facilitating the 3D reproduction of artworks and, contextually, to make their exploration possible and more meaningful for blind users is becoming increasingly relevant in society. Accordingly, the creation of integrated systems including both tactile media (e.g., bas-reliefs) and interfaces capable of providing the users with an experience cognitively comparable to the one originally envisioned by the artist, may be considered the next step for enhancing artworks exploration. In light of this, the present work provides a description of a first-attempt system designed to aid blind people (BP) in the tactile exploration of bas-reliefs. In detail, consistent hardware layout, comprising a hand-tracking system based on Kinect® sensor and an audio device, together with a number of methodologies, algorithms and information related to physical design are proposed. Moreover, according to experimental test on the developed system related to the device position, some design alternatives are suggested so as to discuss pros and cons.

Keywords: 3D reconstruction | Blind people | Hand-tracking system | Kinect sensor

Abstract: Reverse Engineering (RE), also known as "CAD reconstruction", aims at the reconstruction of 3D geometric models of objects/mechanical parts, starting from 3D measured data (points/mesh). In recent years, considerable developments in RE were achieved thanks to both academic and industrial research (e.g. RE software packages). The aim of this work is to provide an overview of state of the art techniques and approaches presented in recent years (considering at the same time tools and methods provided by commercial CAD software and RE systems). In particular, this article focuses on the "constrained fitting" approach, which considers geometrical constraints between the generated surfaces, improving the reconstruction result. On the basis of the overview, possible theoretical principles are drafted with the aim of suggest new strategies to make the CAD reconstruction process more effective in order to obtain more ready/usable CAD models. Finally, a new RE framework is briefly outlined: the proposed approach hypothesizes a tool built within the environment of an existing CAD system and considers the fitting of a custom-built archetypal model, defined with all the a-priori known dimensions and constraints, to the scanned data.

Abstract: Hand impairments represent a significant category of injuries, which can be limiting and impeding in the execution of Activities of Daily Living (ADLs). As can be widely appreciated in scientific literature, a great number of solutions has been proposed in last years for rehabilitating and assisting the patient in both mechanical (e.g. object manipulation) and also social tasks (e.g. shaking hands). Among the numerous approaches, robotic Hand Exoskeleton Systems (HES) represent a vast class of solutions to the problem, as they have several advantages. Contrarily to functional electrical stimulation techniques, for example, HES devices are less invasive and entail to a lesser induced muscular fatigue. In the present work, the authors propose the redesign of a HES robotic device developed at the University of Florence, by means of Topological Optimization (TO) techniques. Even if the existing device is already functional and tested it is still characterized by high encumbrances and masses, in disrespect to the functional requirements. The redesign process has been addressed to a future production of the final object prototype in a titanium alloy, by means of an Electron Beam Melting (EBM) 3D printing machine. The entire procedure was carried out starting from a complete kinematic and dynamic study, followed by the application of TO techniques and it was finally validated by Finite Element Method (FEM) analysis. A single-finger mechanism prototype has been fabricated through additive manufacturing (by means of PolyJet technology) to test the ergonomics and aesthetics of the device. The problem is introduced and contextualized in the Introduction section, while the methodology is subsequently extensively explained, followed by the presentation of the results. In the Conclusion section, the discussion of the process and the result is presented, while possible improving and developments are briefly hinted at.

Abstract: Blind people are typically excluded from equal access to the world’s visual culture, thus being often unable to achieve concrete benefits of art education and enjoyment. This is particularly true when dealing with paintings due to their bi-dimensional nature impossible to be explored using the sense of touch. This may be partially overcome by translating paintings into tactile bas-reliefs. However, evidence from recent studies suggests that the mere tactile exploration is often not sufficient to fully understand and enjoy bas-reliefs. The integration of different sensorial stimuli proves to dramatically enrich the haptic exploration. Moreover, granting blind people the possibility of autonomously accessing and enjoying pictorial works of art, is undoubtedly a good strategy to enrich their exploration. Accordingly, the main aim of the present work is to assess the feasibility of a new system consisting of a physical bas-relief, a vision system tracking the blind user’s hands during “exploration” and an audio system providing verbal descriptions. The study, supported by preliminary tests, demonstrates the effectiveness of such an approach capable to transform a frustrating, bewildering and negative experience (i.e. the mere tactile exploration) into one that is liberating, fulfilling, stimulating and fun.

Keywords: Blind people | Cultural heritage | Hand tracking | Human-computer interaction