Product Design Trends within the Footwear Industry: A Review

: Computer technology influences the capability to enhance the functionality of manufacturing and product design technologies. Innovations in computational design and digital manufacturing empower designers and manufacturers to create novel representations and algorithms for designing, analyzing, and planning the production of highly complicated products achievable through state-of-the-art technology. Various principles, including computational physics, geometric reasoning, and automated spatial planning, enable engineers to generate entirely new categories of products in the footwear industry. This study aims to review the methods and tools that have been published in the literature for the last twenty years, and provide a better understanding of the parameters, tools


Introduction
Even today, owing to the limited capabilities of design software, designers frequently find themselves resorting to more traditional methods and techniques, often resorting to manual craftsmanship, for designing and manufacturing shoe components.Emerging technologies and parametric design offer avenues to optimize the creation and construction of intricate geometries, indicated products, and footwear tailored to individual consumers' needs.The need to reduce production time, costs, and material usage, along with effective waste management, forces the adoption of contemporary and efficient manufacturing methods.The evolving market landscape reflects the changing demands of consumers, who increasingly desire active involvement in the shoe design process, prompting shifts in design practices.While traditional design methodologies have long been the basis of shoe production, evolving design trends, combined with the necessity for greater adaptability and consumer preferences, are driving the adoption of algorithmic design techniques [1].This approach not only overcomes many constraints of traditional design, enhancing both the geometric details of shoe shapes and the utilization of innovative manufacturing technologies but also increases opportunities for personalized design solutions, tailored to specific requirements (e.g., product dimensions, color options, morphological shape, depending on the physical characteristics of the user).As previously noted, the future of footwear development is deeply influenced by the integration of advanced technologies (such as 3D printing, 3D scanning, V-Ray rendering, 3D knitting, and sensor technology) across various stages of design and manufacturing [2][3][4][5][6][7][8][9][10][11][12][13][14][15].As these technologies continue particularly among the elderly [15].Moreover, consumers should be aware of the essential criteria for selecting shoes before making a purchase.This awareness is increasingly vital, given the prevailing consumer trend towards personalized products that align closely with individual preferences.Such emphasis on personalization is prepared to become even more imperative in the years ahead.
The main objectives of the article are to document and clarify the main areas for (1) designing footwear with new technologies, (2) manufacturing footwear with new technologies, (3) controlling footwear with new technologies, and (4) personalizing footwear to each user with new technologies.

Research Methodology
In the initial phase of the research methodology, it was deemed necessary to categorize the literature review based on the year of publication, as shown in Figure 1.This approach allows for a clear understanding of the footwear industry's development.Specifically, as depicted in the chart below, there has been steady growth in the industry over the past two decades, with a significant boom in 2016 and a notable acceleration in the years 2019-2021.An important role was played by the emergence and use of new production technologies, enhancing this result.However, significant efforts had already been made earlier for this industry to thrive and experience this rise.A notable observation is the growing interest in the footwear industry, both in terms of research and industrial activity.However, this does not imply the absence of areas for improvement, extending from the design phase to the production processes.Finally, as discussed below, there is a need for continued research and exploration of new methods, technologies, materials, and cultural aspects to drive the evolution of footwear, promising ever more original yet functional footwear designs.particularly among the elderly [15].Moreover, consumers should be aware of the essential criteria for selecting shoes before making a purchase.This awareness is increasingly vital, given the prevailing consumer trend towards personalized products that align closely with individual preferences.Such emphasis on personalization is prepared to become even more imperative in the years ahead.
The main objectives of the article are to document and clarify the main areas for (1) designing footwear with new technologies, (2) manufacturing footwear with new technologies, (3) controlling footwear with new technologies, and (4) personalizing footwear to each user with new technologies.

Research Methodology
In the initial phase of the research methodology, it was deemed necessary to categorize the literature review based on the year of publication, as shown in Figure 1.This approach allows for a clear understanding of the footwear industry's development.Specifically, as depicted in the chart below, there has been steady growth in the industry over the past two decades, with a significant boom in 2016 and a notable acceleration in the years 2019-2021.An important role was played by the emergence and use of new production technologies, enhancing this result.However, significant efforts had already been made earlier for this industry to thrive and experience this rise.A notable observation is the growing interest in the footwear industry, both in terms of research and industrial activity.However, this does not imply the absence of areas for improvement, extending from the design phase to the production processes.Finally, as discussed below, there is a need for continued research and exploration of new methods, technologies, materials, and cultural aspects to drive the evolution of footwear, promising ever more original yet functional footwear designs.After gathering a sufficient number of scientific documents, the primary objective of this research was established: to contribute towards the development of footwear products.It was discovered that the application of new technological methods is essential for the accurate design, control, and optimal construction of shoes and their individual components.These advancements yield positive outcomes for the footwear industry, enhancing its competitiveness and meeting the evolving needs of consumers.Furthermore, Designs 2024, 8, 49 4 of 27 the continuous development of expertise contributes to the creation of shoes that fulfill both functional and aesthetic requirements of users.Consequently, emerging trends can be increasingly addressed.The research review undertaken was focused on this sector.
Figure 3 illustrates the number of works in each proposed category, separately categorized by year of publication.During these twenty years, either the methods of design, construction, control, or even the target groups to which they were addressed have changed.In all four charts, there is an erratic overall increase in studies, especially over the last five years in all categories.Particularly noteworthy are the categories "Digital Manufacturing Technologies" and "Target Group", which, according to the collected studies, can shed light on research trends and corresponding gaps in the specific field.
After gathering a sufficient number of scientific documents, the primary objective of this research was established: to contribute towards the development of footwear products.It was discovered that the application of new technological methods is essential for the accurate design, control, and optimal construction of shoes and their individual components.These advancements yield positive outcomes for the footwear industry, enhancing its competitiveness and meeting the evolving needs of consumers.Furthermore, the continuous development of expertise contributes to the creation of shoes that fulfill both functional and aesthetic requirements of users.Consequently, emerging trends can be increasingly addressed.The research review undertaken was focused on this sector.
Figure 3 illustrates the number of works in each proposed category, separately categorized by year of publication.During these twenty years, either the methods of design, construction, control, or even the target groups to which they were addressed have changed.In all four charts, there is an erratic overall increase in studies, especially over the last five years in all categories.Particularly noteworthy are the categories "Digital Manufacturing Technologies" and "Target Group", which, according to the collected studies, can shed light on research trends and corresponding gaps in the specific field.The current research review focused on shoe design and manufacturing.Through targeted exploration and research across various aspects of footwear, the literature was categorized into four main directions: Design, Digital Manufacturing Technologies, Simulation Control Methods, and Target Group.Table 1 provides an overview of the research work conducted, presenting these categories along with their respective subcategories.
The first category encompasses research focusing on parametric or traditional shoe design methodologies.The second category encompasses research that explores new technologies such as 3D printing, 3D scanning, 3D knitting, sensors, virtual and augmented reality, which increasingly contribute to the holistic design process of shoes and their individual components.The third category includes control methods involved in testing and research, such as Finite Element Analysis and others.Finally, the fourth category is centered on users and user groups (Professional and Medical), addressing the designer's considerations regarding user needs and preferences.The current research review focused on shoe design and manufacturing.Through targeted exploration and research across various aspects of footwear, the literature was categorized into four main directions: Design, Digital Manufacturing Technologies, Simulation Control Methods, and Target Group.Table 1 provides an overview of the research work conducted, presenting these categories along with their respective subcategories.The first category encompasses research focusing on parametric or traditional shoe design methodologies.The second category encompasses research that explores new technologies such as 3D printing, 3D scanning, 3D knitting, sensors, virtual and augmented reality, which increasingly contribute to the holistic design process of shoes and their individual components.The third category includes control methods involved in testing and research, such as Finite Element Analysis and others.Finally, the fourth category is centered on users and user groups (Professional and Medical), addressing the designer's considerations regarding user needs and preferences.
Table 2 depicts a significant amount of research work conducted, organized according to the aforementioned directions, and further separated based on the publication source type, whether it is a journal or a conference paper.

Design
Design constitutes the initial phase in the production of footwear, wherein emerging fashion trends and consumer demands mainly shape the final geometric form.To meet these evolving requirements, designers select appropriate design tools tailored to each scenario.The first subcategory encompasses computational design, wherein automated processes, guided by parameters specified by the designer, enhance both the design process and the resulting outcome.Conversely, the second subcategory, Computer-Aided Design (C.A.D.), encompasses more traditional and conventional design methodologies.

Computational Design
Computational Design utilizes computational algorithms and tools to optimize design processes, facilitating rapid prototyping and iteration.By harnessing the power of computing, designers can explore complex design spaces, leading to innovative solutions that might not be feasible through traditional methods alone.Computational design plays a significant role in shoe design, revolutionizing the way footwear is created and manufactured.Kuwer Bugin et al. [16] introduced a process for designing and manufacturing a shoe midsole through parametric design, utilizing software such as Rhinoceros TM and Grasshopper TM .The primary shape of the midsole is derived from a standard sole, with key variables, such as point density, pressure values, and sole thickness modifiable to define its final form.This process results in the formation of 3D Voronoi cells.Additionally, the final form is 3D printed using rigid polylactic acid (PLA), enabling the observation of real-world performance through testing.These advancements herald a new approach to shoe design, catering to the individual aesthetic and functional needs of each consumer.Di Roma [17] highlighted the significance of modern digital shoe design processes, particularly focusing on 3D parametric design with user-centric principles.This approach not only enhances traditional handmade shoe production but also offers interactivity, comfort, and safety to users.Integration with Industry 4.0 technologies further enhances competitiveness in the industry (i.e., customization capabilities through a computational design approach).
Amorim et al. [18] developed a shoe sole based on an algorithm, utilizing a single material with diverse properties and 3D printing technology.This approach simplifies production and facilitates recycling.By leveraging various material manufacturing systems (MMS) and considering diverse foot requirements, the researchers generated customizable and functional footwear.Their investigation also included analyzing foot measurements on a case-by-case basis, further enhancing the adaptability and effectiveness of the footwear design.Tian et al. [19,20] utilized parametric design methods to develop customized shoelast designs, significantly reducing the time required for both design and production.By automating calculations and controlling parameters through algorithms, the researchers achieved more personalized and adaptable shoe-last components.Furthermore, their focus [20] on methodically designing shoe-lasts based on parametric principles offers several benefits, including time and cost savings in both the design and production phases, while catering to the individual needs of consumers.By integrating feature parameters with software, the overall process of shoe-last design is enhanced, resulting in greater customization and competence.Zhang et al. [21] concentrated on parametrically designing the heel of women's shoes to address the demand for personalized footwear in the industry.Through the automatic and rapid modification of model parameters, the research demonstrates effective and efficient outcomes.Furthermore, the application of parametric design methods extends beyond sole components to other parts of footwear.In another reference [22], the significance of the instep in the shoe manufacturing process is emphasized.The authors developed a parametric calpod design system for custom production.By setting parameter values, the system adjusts curved lines on each consumer's foot accordingly.This approach aims to reduce production costs, time, and the risk of poor fit in the final product.Overall, this innovative method promises to yield positive outcomes for shoe design and mass customization.
Liu et al. [23] introduced a novel approach to footwear design, specifically focusing on cushioning design for shoe soles.By leveraging new modeling technology and parametric software, they developed various models of elementary porous structures for shoe soles, each with distinct geometries and dimensions.Through extensive testing and measurements of plantar pressure, their method demonstrated significant improvements in shock absorption, underscoring its importance in footwear design.Minaoglou et al. [24] utilized a visual programming language, Grasshopper TM , supported by Rhinoceros3D TM to create shoe soles.Integrating parametric design with 3D scanning and printing technologies enabled precise control over the final geometry and prototype, resulting in a diverse display of geometries that enhance customer satisfaction.Song et al. [25] employed parametric design techniques to generate a 3D model of a shoe last.This involved defining custom 3D geometry based on a specific number of points on the foot, facilitated by software such as Rhinoceros TM and Grasshopper TM .The accuracy of the proposed 3D model demonstrates its potential for informing footwear design decisions.
García-Dominguez et al. [26] developed a methodology that integrates three technologies, including parametric software, to enhance the design process.Through a case study focusing on a shoe heel, they illustrated how modifications to the final model can lead to alternative approaches, thereby improving the methodology's complexity, utility, and applicability.This advancement not only enhances ergonomics but also has implications for mass production, offering researchers the opportunity to refine and expand upon the methodology's capabilities.Feijs et al. [27] developed a design methodology based on algorithmic design, generating patterns with a unique aesthetic and approach.This methodology enables clients to personalize their shoe soles, leveraging Voronoi diagrams to offer a broader range of patterns compared to traditional methods.This approach is compatible with digital fabrication techniques, particularly 3D printing, further enhancing customization possibilities.Finally, Christodoulou et al. [28] concentrated on designing pointe shoes, considering various parameters to ensure proper adaptation to each dancer's foot.Their objective is to optimize performance and prevent injuries by parametrically deriving the geometry of the shoe based on leg morphology and other defined parameters.This approach prioritizes individual fit and functionality, contributing to dancers' overall experience and well-being.

Computer-Aided Design
Computer-Aided Design (CAD) revolutionizes the shoe design process by providing designers with powerful tools for creating, visualizing, and refining footwear concepts.Davia-Aracil et al. [29] introduced a novel methodology aimed at assisting designers in the design and validation of shoe soles.This methodology not only enhances the conceptual design process but also streamlines manufacturing phases.Emphasizing both structural and functional aspects, the approach enables designers to determine quantitative and qualitative values essential for meeting international safety standards for shoe design, such as coefficients of abrasion and slip resistance.Luximon and Luximon [30] developed a new software dedicated to shoe-last design, offering designers real-time intervention and modification capabilities based on foot shape measurements.This contrasts with other software options that lack such flexibility.By reducing design phase duration and enhancing comfort and sustainability for future users, this software revolutionizes the design process for this critical component of shoes.Wang et al. [31] contributed to the development of a CAD program designed for easy and rapid personalized shoe-last design, aligning with the needs of modern footwear manufacturing.Their focus on interactive deformation of shoe-last forms, coupled with a novel method rooted in parametric design, facilitates efficient design iteration.Additionally, the resulting shoe-last types can be saved and utilized globally, meeting diverse design requirements for these essential shoe components.
Leshchyshyn et al. [32] formulated a novel method for shaping the bottom parts of shoes, incorporating a more artistic approach to analyze and classify forms, resulting in the automatic generation of modern shapes.This approach enhances the effectiveness of footwear design and simplifies manufacturing processes through technological integration.Utilizing sketches and 3D models, designers determine the shape of shoe bottom parts, followed by the analysis and estimation of parameters such as stability, strength, and materials, reflecting the increasing complexity designers face in their considerations.Sambhav et al. [33] focused on digital design of shoe lasts, employing specific and automated steps in the design process.Starting from leg scans, B-spline curves are adjusted to fit the leg geometry, concluding in a final design suitable for sampling or mass production.
Luo et al. [34] concentrated on enhancing the relationship between the foot and leg through an integrated design system.By leveraging database technology for automatic foot classification and model extraction, the system facilitates precise fitting of footwear to individual foot characteristics, thus improving the traditional footwear design process.
Figure 4 illustrates the categorization related to the Design module, while also highlighting trends that stood out within it.More specifically, in the two subcategories of the Designs 2024, 8, 49 9 of 27 first section, computational design and CAD, the optimization and algorithm trends were observed in one and digital presentation and design software in the other, respectively.mated steps in the design process.Starting from leg scans, B-spline curves are adjusted to fit the leg geometry, concluding in a final design suitable for sampling or mass production.
Luo et al. [34] concentrated on enhancing the relationship between the foot and leg through an integrated design system.By leveraging database technology for automatic foot classification and model extraction, the system facilitates precise fitting of footwear to individual foot characteristics, thus improving the traditional footwear design process.
Figure 4 illustrates the categorization related to the Design module, while also highlighting trends that stood out within it.More specifically, in the two subcategories of the first section, computational design and CAD, the optimization and algorithm trends were observed in one and digital presentation and design software in the other, respectively.

Digital Manufacturing Techologies
Digital manufacturing technologies are driving significant growth in the footwear industry, offering new possibilities in design and manufacturing that result in higher quality footwear products.The first subcategory encompasses 3D printing, which allows for the production of shoe parts with virtually limitless final geometries.The second subcategory involves 3D scanning, a technology that provides precision through the digitization of physical models, facilitating construction and quality control processes.Next, 3D knitting emerges as an innovative technique, strengthening the textile sector by enabling complex and customized designs.Virtual and augmented reality constitute the fourth category, offering experiences for users through virtual environments where they can interact with virtual models in real time, enhancing their online shopping experience.Finally, sensors represent the fifth subcategory, integrated into footwear parts to gather measurements that provide valuable insights for users, improving the functionality and usability of the shoes.

3D Printing
Three-dimensional printing is revolutionizing the shoe industry by offering innovative solutions for design, customization, manufacturing, and sustainability.As the technology continues to advance, there is an expectation for further integration of 3D printing into all aspects of shoe production, leading to more personalized, sustainable, and highperformance footwear options.Spahiu et al. [35] leveraged new 3D technologies such as 3D scanning, 3D printing, and 3D simulation in the design process.They utilized scanned human models to apply clothing and footwear digitally, comparing them with their physical counterparts to demonstrate the reliability of FDM (fused deposition modeling) technology.This underscored the significance of new manufacturing technologies such as 3D scanning and 3D printing in the design process, particularly in the realm of customized

Digital Manufacturing Techologies
Digital manufacturing technologies are driving significant growth in the footwear industry, offering new possibilities in design and manufacturing that result in higher quality footwear products.The first subcategory encompasses 3D printing, which allows for the production of shoe parts with virtually limitless final geometries.The second subcategory involves 3D scanning, a technology that provides precision through the digitization of physical models, facilitating construction and quality control processes.Next, 3D knitting emerges as an innovative technique, strengthening the textile sector by enabling complex and customized designs.Virtual and augmented reality constitute the fourth category, offering experiences for users through virtual environments where they can interact with virtual models in real time, enhancing their online shopping experience.Finally, sensors represent the fifth subcategory, integrated into footwear parts to gather measurements that provide valuable insights for users, improving the functionality and usability of the shoes.

3D Printing
Three-dimensional printing is revolutionizing the shoe industry by offering innovative solutions for design, customization, manufacturing, and sustainability.As the technology continues to advance, there is an expectation for further integration of 3D printing into all aspects of shoe production, leading to more personalized, sustainable, and highperformance footwear options.Spahiu et al. [35] leveraged new 3D technologies such as 3D scanning, 3D printing, and 3D simulation in the design process.They utilized scanned human models to apply clothing and footwear digitally, comparing them with their physical counterparts to demonstrate the reliability of FDM (fused deposition modeling) technology.This underscored the significance of new manufacturing technologies such as 3D scanning and 3D printing in the design process, particularly in the realm of customized shoes.The authors demonstrated the application of these technologies in redesigning a shoe model, wherein manufacturing design tools were utilized to shape the form and aesthetics, highlighting their transformative impact [36].Gong and Luping [37] listed the advantages offered by 3D technology tools in the footwear industry.An example of a digital shoe was provided, detailing its design and manufacturing process, showcasing the efficacy and versatility of these tools in modern footwear production.Lim [38] envisioned how 3D printing technology could revolutionize the production of shoes by reinterpreting patterns from traditional culture to create customized designs.This innovative approach opens up a new design frontier, resulting in unique products tailored to specific consumers.
Lin and Chen [39] explored the feasibility of manufacturing women's high-heeled shoes using 3D printing technology.Their study focused on addressing ergonomic and comfort issues while selecting suitable materials and assembly methods.By leveraging 3D printing, they aimed to streamline production, ultimately saving both time and costs.Armillotta et al. [40] investigated the custom design and production of high-heeled shoes, recognizing the need to digitally manufacture heel components for assembly.Through 3D printing, they produced samples for evaluation, highlighting the applicability of this method.Future research will further explore the optimal shape of heel components.Salles and Gyi [41] outlined a process for customizing shoe soles, beginning with foot scanning and culminating in prosthetic construction using polyamide material.Positive feedback was received during testing, demonstrating the comfort and effectiveness of the customized soles.

3D Scanning
Three-dimensional scanning technology is reshaping the shoe industry by revolutionizing the way shoe designs are created, customized, and manufactured.This technology is playing a crucial role in the shoe industry by enabling customization, improving design efficiency, enhancing product quality, and providing innovative solutions for foot measurement and analysis.Telfer and Woodburn [42] highlight the advantages of modern 3D scanning systems, emphasizing their application in various fields due to their design capabilities and cost-effectiveness.They specifically mention foot scanning for the study and production of custom footwear as a prominent application.Al-Kharaz and Chong [43] gathered basic information on shoe production, considering foot changes during walking.They employ photogrammetric techniques using mobile phone shots to create three-dimensional foot models, facilitating the understanding of foot dynamics during walking.Shariff et al. [44] utilize a 3D foot scanner and anthropometric measurements to establish a new standard shoe size, enabling manufacturers to create shoes tailored to specific foot sizes and shapes.Lee and Whang [45] leverage 3D scanning technology to collect data on foot shapes from a specific demographic, allowing for the design of more tailored and specific shoes for consumers.Butdee and Tangchaidee [46] investigate typical Thai shoe sizes through 3D scanning of feet across various demographic groups.Their findings inform the customization of shoe sizes for individuals as well as for the Thai population in general.

3D Knitting
Three-dimensional knitting technology is changing the shoe industry by offering innovative solutions for footwear design, manufacturing, and customization.Overall, 3D knitting technology is transforming the shoe industry by offering efficient, customizable, and sustainable solutions for footwear design and manufacturing.The further integration of 3D knitting into all aspects of shoe production is leading to more personalized, highperformance, and aesthetically pleasing footwear options.Duarte et al. [47] underscored the transformative impact of three-dimensional knitting technology on textile production, particularly in sportswear and footwear.By comparing conventional techniques with modern knitting processes, they highlighted the advantages of the latter, including time and cost savings, as well as enhanced consumer experiences.Power [48] emphasized the significance and innovation of three-dimensional knitting machines as modern production techniques.By showcasing examples from various industries, including sports and footwear, they illustrated the potential of this technology to revolutionize design and knitting processes, enabling the creation of complex shapes and integration with smart materials.Kumar B. and Gupta [49] investigated 3D knitting as a shoe manufacturing process, particularly in the context of sports shoes.Their study demonstrated that 3D knitting enhances productivity and sustainability by reducing material costs, production time, and waste.Additionally, the resulting footwear can be customized to meet the specific needs of individual customers.Wicaksono et al. [50] applied 3D knitting technology to fabricate fabrics embedded with specially adapted sensors.These sensors were designed to identify activity levels based on pressure concentration on the fabric surfaces.By integrating digital circuits for operation and data collection, they successfully tested the sensors on fabric squares and socks, showcasing the versatility and potential applications of 3D knitting in sensor technology.VR and AR technology are transforming the shoe industry by offering immersive, interactive, and personalized experiences for consumers, designers, and retailers alike.Sim et al. [51] developed a fall detection system designed for the elderly, different from conventional methods by integrating sensors into the shoes.This innovative approach not only ensures better placement of sensors but also considers factors like battery adjustment to optimize size and weight during design and usage.Nilpanapan and Kerdcharoen [52] embedded various sensors into shoe soles to monitor the walking patterns of elderly individuals within their homes, enabling real-time data transmission to their relatives.This system facilitates instant information sharing, including through social networks, enhancing monitoring and support for elderly individuals.Kong and Tomizuka [53] proposed a method for detecting gait phases by incorporating sensors into shoe soles, enabling the monitoring and analysis of steps through algorithmic processing.Jung et al. [54] developed smart shoes equipped with sensors in their soles to gather data and provide insights into changes occurring within the user's body, offering valuable information for health monitoring and management.Truong et al. [55] introduced a wearable sensor system placed on shoes and wrists to monitor and recognize users' daily activities, aiming to improve their daily routine.The positioning of sensors was optimized to ensure reliable data collection, with the collected information aimed at improving user well-being and quality of life.
Aminian et al. [56] developed motorized shoes aimed at assisting the gait and balance of the elderly.These shoes feature soles that adjust inclination based on posture and gait, facilitating training activities targeting specific muscle groups while simultaneously controlling sole inclination during various movements.Huang et al. [57] created smart shoes capable of human identification based on the conception and analysis of human gait.This innovation enables real-time user ranking by characterizing gait performance effectively, enhancing applications such as security and personalized healthcare.Li et al. [58] introduced wearable sensor shoes equipped with inertial sensors for gait analysis.These sensors, tailored to fit within the shoes, collect data on parameters such as ground forces, torques, and joint angles, ensuring accurate measurements and results.Proper placement within the shoes enhances reliability and effectiveness in gait analysis.

Sensors
Sensors in the shoe industry are transforming footwear into intelligent, data-driven devices that enhance performance, promote health and safety, and improve the overall user experience.Nordahl et al. [59] developed a gait simulation system that integrates tactile and auditory sensations into a shoe.Through experiments, they aimed to enhance users' ability to recognize different walking surfaces using these specific senses.Wang et al. [60] developed a system by integrating it with the Smart Shoe to enhance the walking experience, particularly for individuals facing difficulties with uneven surfaces or obstacles.They conducted experiments and distributed questionnaires to verify the accuracy and reliability of the system.Lécuyer et al. [61] introduced a novel approach to improve walking experiences both indoors and outdoors.Their system projects artificial footstep sounds using pressure sensors, enhancing the overall walking experience, and potentially finding applications across various sectors.Son et al. [62] developed a tactile pair of shoes (RealWalk) that interacts with both physical ground surfaces and virtual reality environments.By incorporating magneto-realistic fluid and virtual scenes, they aimed to create realistic sensations of ground deformation and provide immersive interaction scenarios.Yang et al. [63] manufactured VR shoes utilizing alternating magnetic fields and magnetorheological fluid to create a more realistic sense of contact with different surfaces.This innovative construction enhances the involvement in virtual reality environments.Strohmeier et al. [64] focused on creating virtual materials through a prototype shoe, utilizing motion sensors to simulate walking effects.They presented case studies to showcase the potential applications and possibilities of the shoe in creating virtual experiences.
Jiang et al. [65] developed a theoretical model focusing on the relationship between consumers' perceived interactivity and intrinsic value, particularly in the context of ecommerce for footwear purchases.They advocate for the utilization of augmented reality (AR) technologies to enhance or create new mobile applications, aiming to provide consumers with improved services and experiences during their footwear shopping journey.Chu et al. [66] stress the significance of augmented reality in modern e-commerce, particularly in enabling anthropocentric design evaluation.They highlight the capability of AR to allow customers to try on real-time 3D shoe models on their mobile devices, improving the interactive shopping experience.Eisert et al. [67] introduced a virtual mirror using augmented reality, aiming to replace physical mirrors with digital ones.This technology enables customers to view and test virtual shoes against real products in real time, offering additional options and refining the shopping experience.Furthermore, Eisert et al. [68] utilized augmented reality techniques to enhance the real-time display of custom sports shoes.They developed a new algorithm to replace mirrors with cameras that detect motion, providing customers with an interactive and personalized experience when trying on sports shoes.
An advanced shoe prototype was created to aim at enhancing online shopping experiences by reducing the incidence of incorrect shoe size choices among consumers [69].This prototype allows users to compare their foot shape with the shoes before making an online purchase, significantly decreasing the rate of returns for online orders.Additionally, the incorporation of virtual reality technology enables customers to assess both the aesthetics and functionality of the shoes, providing them with greater autonomy in their online search for footwear.The research aims to extend these advancements to other electronic markets for industrial products, further enhancing consumer satisfaction.As a result of the aforementioned process, a virtual shoe construction system was developed utilizing augmented reality (AR) technology for foot detection [70].The system relies on seven registered leg types combined with a light detection and range sensor to determine foot shapes and sizes in real time.The effectiveness of this approach suggests its potential to replace traditional measurement techniques, particularly for vulnerable patients.Future research goals include identifying factors such as age and gender that may influence measurement outcomes, thereby refining the system's accuracy and applicability.
Figure 5 illustrates the categorization related to the Digital Manufacturing Technologies module.At the same time, in each of its five sub-categories, the main trend prevailing in them emerges.In 3D printing, mass production, in 3D scanning, measurements, in 3D knitting, complex shapes, in sensors, movement and trends, and in virtual and augmented reality, visualization and interaction.

Simulation Control Methods
Simulation methods are categorized into two subcategories in research.The first subcategory involves Finite Element Analysis (FEA) methods, which conduct virtual tests to extract valuable insights regarding the durability, comfort, and lifespan of shoe components.These simulations enable researchers to assess the structural integrity and performance of various shoe parts under different conditions.The second subcategory focuses

Simulation Control Methods
Simulation methods are categorized into two subcategories in research.The first subcategory involves Finite Element Analysis (FEA) methods, which conduct virtual tests to extract valuable insights regarding the durability, comfort, and lifespan of shoe components.These simulations enable researchers to assess the structural integrity and performance of various shoe parts under different conditions.The second subcategory focuses on control methods aimed at optimizing design through user testing.By incorporating feedback from users, these methods seek to enhance the overall design of footwear, ensuring it meets the needs and preferences of consumers.This approach allows for iterative improvements based on real-world usage scenarios, leading to better-performing and more user-friendly shoe designs.

Finite Element Analysis (FEA)
Finite Element Analysis is a valuable tool in the footwear industry, enabling designers to optimize shoe designs for performance, comfort, durability, and fit.By simulating the behavior of shoe components under various conditions, FEA helps designers create footwear that meets the demands of athletes, consumers, and specialized applications.Moghaddam et al. [71] developed a modeling framework capable of estimating wear evolution on shoe soles using Finite Element Analysis and mathematical equations.Their framework, validated through experimental results, provides realistic predictions of sole wear.By considering these predictions, it can contribute to the design and construction of more durable and slip-resistant shoes.Cheung and Nigg [72] created a three-dimensional model of the human foot and ankle using the finite element method.This detailed model serves as a reliable tool for parameter control in both understanding the human foot and designing shoes.Franciosa et al. [73] carried out experimental tests and finite element simulations to identify the main factors influencing shoe comfort.Their research revealed that sole thickness and material are the primary factors affecting comfort during walking.Antunes et al. [74] explored the use of Finite Element Analysis to understand the mechanical behavior of the human foot and its relationship to comfort.By analyzing a 3D model, they have found that Finite Element Analysis is a promising method for designing shoe insoles that provide optimal comfort during walking.
Chen et al. [75] investigated the properties required for insoles to reduce plantar pressure by conducting a three-dimensional finite element study of the foot and footwear.They identified the thickness of the insole and the distribution of plantar pressure on the metatarsals as key parameters.Their simulations, conducted under walking conditions, revealed that to alleviate foot pressure, the insole must be sufficiently thick and create a uniform compression pattern near the metatarsals.Song et al. [76] aimed to improve athletic shoes through finite element modeling, creating a 3D model to test interactions between the foot and the shoe and understanding conditions.Using scientific CT (Computed Tomography) images, they digitally constructed foot and shoe models, as well as analyzed loading conditions and sensitivity during walking to identify optimal material properties for the sole.Validation using the Bland-Altman method confirmed the accuracy of their simulations, facilitating footwear design optimization.
Verdejo and Mills [77] utilized Finite Element Analysis (FEA) to examine tension distribution in a sneaker's heel and midsole.Their analysis revealed that prolonged use and running over certain distances lead to reduced heel absorption due to foam wear in this area.Hale et al. [78] employed a 3D finite element (FE) model to investigate the friction coefficient during walking, focusing on the influence of sole groove shapes on slip resistance in rubber footwear.Their study demonstrated a significant effect of sole surface and ground interaction on the friction coefficient, suggesting that different groove shapes and materials could further improve slip resistance.Yu et al. [79] developed a 3D model of a human foot and accurately fitted a high-heeled shoe for Finite Element Analysis.By studying foot movement during gait and associated changes in foot joints, heels, and toes, they demonstrated the potential of computational approaches in virtual environments for realistic evaluation and optimization of footwear design.Wang et al. [80] explored the impact of high-heeled shoe height on treating plantar fasciitis using finite element method (FEM) and musculoskeletal modeling.Their study indicated that increasing heel height during walking may exacerbate plantar fascia tension, suggesting the need for further investigation into therapeutic benefits of heel elevation.
Braun and Baritz [81] focused on correcting orthopedic diseases using special insoles for the feet, analyzing finite element models.By testing prototypes, they demonstrated the endurance of these insoles during walking and standing, validating their effectiveness.Huang et al. [82] assessed shoe strength using Finite Element Analysis, particularly examining slip resistance between the outsole and contacting surface.Their study admitted the utility of Finite Element Analysis for such evaluations, highlighting the importance of designing high-slip outsoles to prevent falls while walking.Gupta and Chanda [83] investigated outsole patterns and geometry in relation to shoe-to-floor adhesion, particularly focusing on slip control on wet floors.Their experiments revealed that selected patterns can effectively reduce the risk of shoe slippage, providing valuable insights for designing safer footwear.

Other Control Methods
Control methods in the shoe industry play a crucial role in ensuring product quality, process efficiency, regulatory compliance, and customer satisfaction.Nachtigall [84] developed a shoe research model for data collection, employing separate approaches including pressure sensors on the sole and studying wear over time.These methods facilitate questions regarding shoe design, accuracy, and viability.Weisz et al. [85] simulated and altered the pressures experienced by the viscoelastic midsole (by 3D scanner ARTEC EVA) of a sports shoe during running.Their findings highlighted the importance of considering fundamental shoe elements such as properties, components, and age for accurate modeling of heel-shoe interactions.Moghaddam et al. [86] created a model to calculate the coefficient of friction between the shoe and its sole using finite elements of multiple friction scales.This aims to prevent slipping and falls, reducing associated injuries.
Morio et al. [87] focused on the absorbency quality of the midsoles in sports shoes.They evaluated the viscoelastic properties between new and used shoes to assess their effectiveness over time.Yang et al. [88] investigated parameters crucial for optimal sports shoe design and reducing plantar pressure.They applied the Taguchi method to determine the best combination of these parameters and validated the model using Ansys TM .Their findings identified specific values for inner and outer sole materials and thicknesses to improve plantar pressure on the heel.Li et al. [89] measured coefficients of friction between shoes and floors using various patterns and sole designs.This research aimed to identify the most suitable shapes and dimensions for shoe soles.Hennig [90] examined shoe tests conducted according to specific protocols regarding material and properties of athletic shoes.His findings indicated improvements over the years, particularly in shoe quality against vibration, leading to increased athlete satisfaction and longevity of high-quality shoes based on the distance athletes travel with them.
Navarro-Cano et al. [91] conducted research on orthopedic shoes, particularly their importance during the post-surgical period.They focused on controlling the distribution of load on the foot with and without orthopedic shoes, aiming to optimize foot recovery.da Silva Azevedo et al. [92] compared data from runners wearing different types of sports shoes (conventional, transitional, minimalist, and barefoot).They concluded that transitional shoes serve as an intermediate state of mechanical load, potentially facilitating the transition from conventional to minimalist running shoes.Hong et al. [93] investigated the impact of overall contact inserts on the comfort of women's high-heeled shoes.Their research found that while higher heel heights generally decrease comfort, using an overall contact insert can increase comfort when wearing high heels.Khoury et al. [94] examined biomechanical manipulations caused by footwear and their correlation with the position of the center of pressure orbit during walking.Their research aimed to understand how footwear affects foot biomechanics during movement.
Derlatka and Bogdan [95] developed a system using sensors and process data to identify the type of shoes users wear based on their gait.This contributes to the advancement of biometrics and improves the accuracy of similar methods.Kim et al. [96] aimed to enhance the design and manufacturing processes of footwear by analyzing the effect of materials used for the upper part of casual shoes during walking.Finite element simulation tools were utilized to accurately assess strain and stress values.Jung et al. [97] developed a three-dimensional motion recording system using smart shoes and inertial sensors to analyze and record postures during sports activities.This real-time monitoring system provides continuous and accurate information for improved analysis of body movements.
Figure 6 schematically depicts the categorization associated with the Simulation Control Methods module, while also highlighting notable trends within it.The most important trends observed in the FEA and other control methods subcategories are in the former experimental control and mechanical behavior, while in the latter, they involve data collection and testing.
shoes (conventional, transitional, minimalist, and barefoot).They concluded that transi-tional shoes serve as an intermediate state of mechanical load, potentially facilitating the transition from conventional to minimalist running shoes.Hong et al. [93] investigated the impact of overall contact inserts on the comfort of women's high-heeled shoes.Their research found that while higher heel heights generally decrease comfort, using an overall contact insert can increase comfort when wearing high heels.Khoury et al. [94] examined biomechanical manipulations caused by footwear and their correlation with the position of the center of pressure orbit during walking.Their research aimed to understand how footwear affects foot biomechanics during movement.
Derlatka and Bogdan [95] developed a system using sensors and process data to identify the type of shoes users wear based on their gait.This contributes to the advancement of biometrics and improves the accuracy of similar methods.Kim et al. [96] aimed to enhance the design and manufacturing processes of footwear by analyzing the effect of materials used for the upper part of casual shoes during walking.Finite element simulation tools were utilized to accurately assess strain and stress values.Jung et al. [97] developed a three-dimensional motion recording system using smart shoes and inertial sensors to analyze and record postures during sports activities.This real-time monitoring system provides continuous and accurate information for improved analysis of body movements.
Figure 6 schematically depicts the categorization associated with the Simulation Control Methods module, while also highlighting notable trends within it.The most important trends observed in the FEA and other control methods subcategories are in the former experimental control and mechanical behavior, while in the latter, they involve data collection and testing.

Target Group
In the last category of specific research, the target groups for footwear are often identified based on consumer preferences and needs.Consumers select shoes based on various criteria, including functionality, style, comfort, and performance.Additionally, there is a growing trend towards personalized products tailored to individual customers' preferences and requirements.This trend reflects a shift towards consumer-centric approaches in manufacturing, where companies strive to offer customized solutions to meet the unique needs and desires of each customer.

Professional
The shoe industry often focuses on creating shoes that meet the specific needs and preferences of individuals in various industries and occupations.Piperi et al. [98] emphasized the significance of the human foot and modern trends in footwear design by presenting a comprehensive process for designing and producing customized shoes.By employing technologies such as 3D scanning, 2D and 3D software, and 3D printing, they enabled the creation of personalized shoes that address customers' foot problems.This approach not only benefits customers by providing tailored solutions but also allows designers to maintain better control over all design stages, from prototype models to the final shape and form of the shoes.Clifton et al. [99] considered not only the fundamental parameters required for designing sports shoes but also the specific needs of a particular user group.By profiling this user group, they identified the design features required based on the functional specifications of each subgroup.This approach ensures that the design of sports shoes meets the diverse needs of different user groups, enhancing overall user satisfaction.Kalantari et al. [100] investigated consumers' willingness to purchase mass-customized running shoes, aiming to understand gender differences in product preferences.Their research focused on identifying which product features, such as price, degree of customization, and delivery time, men and women prioritize when purchasing running shoes.The findings highlighted distinct preferences between genders, providing valuable insights for manufacturers and marketers to tailor their offerings to different consumer segments effectively.
Fruet et al. [101] addressed stress control in cycling shoes by utilizing pressure sensor networks placed inside the shoes to identify points of maximum stress during cycling.This data offers valuable insights into the interaction between the cyclist's foot and the shoe sole, particularly during push-off phases, aiding in the development of cycling footwear that optimizes comfort and performance.
Sankar et al. [102] focused their research on studying and designing weightlifting shoes, recognizing a gap in optimizing their control.They employed Finite Element Analysis (FEA) in a digital environment to analyze the physical properties of materials used in the 3D model of the shoe sole.Subsequently, they validated the results obtained from the analysis software by conducting physical tests on the sole.This research provides valuable insights into the properties of weightlifting shoes, such as stress, tension, and deformation, serving as a guideline for optimization for designers and manufacturing companies.Nachtigall et al. [103] followed a specific methodology to design and produce a personalized highheeled shoe for a single user.The shoe's shape, geometry, comfort, aesthetics, materials used in 3D printing, durability, and balance were determined based solely on the user's profile.This approach ensures that the shoe meets the unique needs and preferences of the individual user.Skidan et al. [104] were involved in designing and manufacturing low shoes for school students.They utilized appropriate software and parametric foot models to create the shoes, paying special attention to the upper part of the footwear.This research aims to provide comfortable and durable footwear tailored to the needs of schoolchildren.Golubeva and Pogorelova [105] conducted a study on soles for agricultural shoes, with the goal of identifying the most suitable material for enhancing wear resistance.Through experiments conducted on three-dimensional models, they determined that a combination of two materials and increasing sole thickness maximized wear resistance.This research contributes to improving the durability and performance of agricultural footwear.Spahiu et al. [106] focused on developing a method for calculating and creating personalized footbeds for shoe soles.Considering both aesthetics and pressure distribution, their method aims to design soles that provide optimal support while minimizing material usage.This research offers insights into enhancing comfort and performance through customized shoe sole designs.Greci et al. [107] developed a personalized shoe device called Footglove, which allows customers to try on and select footwear before it is made.This device helps customers find the right size and type of shoe that fits them best, reducing the need for excessive stock in stores.Testing of the device and completion of a questionnaire showed that the mechanism of the device is functional and reliable in providing accurate results.
Spahiu et al. [108] presented a case study for shoe sole design based on the specific geometry of the wearer's foot.Through customized design and topological optimization to control sole pressure, this approach achieves material savings in shoe production while ensuring optimal aesthetics and performance.

Medical
The footwear industry is also focused on designing, producing, and prescribing medical footwear tailored to address various foot-related conditions and improve overall foot health.There is a rapid development and provision of footwear designed to enhance foot health, alleviate pain, and improve mobility for individuals with foot-related conditions or injuries.Tang et al. [109] aimed to optimize a custom shoe sole by designing a porous sole to reduce maximum plantar pressure for each user in a static position.They proposed a lattice structure that can adjust the diameter of struts inside the sole, with future research planned to explore additional factors for further optimization.Fergiawan et al. [110] studied the design of orthotic footwear for individuals with specific foot shapes, using scans of the sole to obtain correct geometry for the inner sole.Simulation models were employed to achieve optimal design parameters and reduce shoe manufacturing time, utilizing CAM (Computer-Aided Manufacturing) and CNC (Computerized Numerical Control) machine techniques along with Taguchi methods.Chapman et al. [111] investigated how specific variable characteristics in the design of arched shoes can affect peak plantar pressure, focusing on diabetic and healthy individuals.Their findings suggest that certain combinations of parameters can lead to balance and pressure relief in different areas of the feet, but further research is needed for standard results.
Pradipta et al. [112] applied Finite Element Analysis to find the optimal material with parameters for mechanical comfort in a shoe insole for diabetics.Their study concluded that Memory Foam is the ideal material due to its good shock absorption and mechanical properties, providing comfort and support for diabetic individuals.
Keukenkamp et al. [113] focused on designing special indoor footwear for individuals with diabetes, recognizing the heightened risk they face with their feet.They aimed to provide a higher quality result compared to standard custom-made footwear already available on the market.To achieve this, they used lighter and softer materials in the construction of these shoes.Feedback from individuals with diabetes who participated in the research indicated that the custom-made shoes were of better quality and provided sufficient relief.Additionally, the lower production costs make these shoes more affordable for the specific target group.Nathan et al. [114] aimed to improve the daily lives of people with vision problems by designing a smart shoe to replace traditional canes.This shoe operates using sensors and sound methods to perceive the environment, allowing users to walk independently.The researchers plan to test the smart shoe in real-world environments, with the goal of enhancing the mobility of visually impaired individuals.
Oh and Suh [115] developed shoe soles specifically designed for elderly individuals with flat feet.They utilized three-dimensional systems in the production process of these shoes.Initially, the feet of the subjects were scanned, both with and without flat feet.Subsequently, the collected data was used to appropriately design and manufacture the insole model, employing 3D printing for this purpose.Cheung et al. [116] focused on understanding the footwear preferences of seniors in Hong Kong.The primary objective was to identify shoes that are both comfortable and aesthetically pleasing for them.By emphasizing these two parameters, the researchers aimed to provide valuable insights to footwear designers, enabling them to better meet the needs and preferences of senior consumers from the outset of the design process.By considering comfort and aesthetics as key factors, designers can make informed decisions regarding materials, color shades, and manufacturing techniques to create footwear that is not only functional but also visually appealing.Moreover, the study suggests that the use of new technological tools, such as 3D printing, holds promise for further enhancing the design and production of footwear tailored to the preferences of seniors.Moufawad el Achkar et al. [117] developed a shoe-integrated system designed to monitor the daily activities of elderly individuals.By analyzing data gathered from walking and other activities, the system provides valuable information such as the type of walking and posture, with the main purpose of identifying any potential risks of falls or weakness.The system utilizes an algorithm to classify these activities accurately, enhancing its effectiveness.Davis et al. [118] discovered that for older women, the primary factors influencing their choice of shoes are aesthetics and comfort, rather than safety.This neglect of safety considerations may lead to an increased risk of falls, injuries, or foot distortions.However, the researchers suggested that combining aesthetics, comfort, and safety in shoes for older women is achievable, provided they are educated on the importance of making choices based on safety.Jellema et al. [119] conducted a literature review focusing on the needs and demands of elderly individuals regarding footwear.They evaluated the effects of shoes on this age group, summarized the characteristics of comfortable shoes, and proposed suitable shoe design suggestions based on documented evidence, aiming to address the specific requirements of the elderly.Figure 7 illustrates the categorization associated with the Target Group unit, while also highlighting notable trends within it within each of its subcategories.More specifically, in the subcategory professional (shoes for various sports, work shoes, as well as shoes for each gender), the trends personalization, adaptability, and identity stood out.In the other subcategory, medical (shoes for the elderly and people with health problems and special needs), injuries, safety, and needs stood out.falls, injuries, or foot distortions.However, the researchers suggested that combining aesthetics, comfort, and safety in shoes for older women is achievable, provided they are educated on the importance of making choices based on safety.Jellema et al. [119] conducted a literature review focusing on the needs and demands of elderly individuals regarding footwear.They evaluated the effects of shoes on this age group, summarized the characteristics of comfortable shoes, and proposed suitable shoe design suggestions based on documented evidence, aiming to address the specific requirements of the elderly.
Figure 7 illustrates the categorization associated with the Target Group unit, while also highlighting notable trends within it within each of its subcategories.More specifically, in the subcategory professional (shoes for various sports, work shoes, as well as shoes for each gender), the trends personalization, adaptability, and identity stood out.In the other subcategory, medical (shoes for the elderly and people with health problems and special needs), injuries, safety, and needs stood out.At this point, to further understand the role of new technologies in the industry's product design, Figure 8 was created.Considering Table 1 and Figures 4-7, the following relationship graph emerged.The purpose of the overall diagram is to centrally present the main stages of shoe production, as well as the interactions between them.
In more detail, and according to the literature research carried out, design is the first step to create a shoe, or a part of it.The way to design its geometry can be performed At this point, to further understand the role of new technologies in the industry's product design, Figure 8 was created.Considering Table 1 and Figures 4-7, the following relationship graph emerged.The purpose of the overall diagram is to centrally present the main stages of shoe production, as well as the interactions between them.either through computational design or traditional CAD.The second step involves new digital production technologies.Three-dimensional printing and 3D knitting contribute to the main creation of the 3D form.Three-dimensional scanning with reverse engineering provides the ability to digitize the 3D shape to form the basis for digitally modifying it.In addition, the contribution of virtual and augmented reality is now very decisive in displaying and promoting, especially in online shopping.Additionally, sensors as a technology have the potential to enhance digital media for their final results.At the same time, in the third step where the control is conducted, data collection can be accomplished either through sensors or mechanical controls and through virtual or real tests.The resulting outcomes, in turn, lead to the approval or redefinition of the design or construction parameters.In the final step, the emerging market trend places the consumer-user at the center.This human-centered model results in the production of footwear products that perfectly suit the needs, characteristics, and personal preferences of each user.However, to achieve this, appropriate cooperation between the new technologies belonging to the previous steps is required.

Summary of Key Research Areas Depicted
The first category of research tasks focuses on the design of various parts of the shoe or the shoe's overall geometry.This category encompasses a total of 18 research papers, with 12 based on parametric design methods and 6 utilizing more traditional CAD design approaches.In the first subcategory, which centers on parametric design, algorithms play a key role in product design.These algorithms are programmed to generate personalized geometry for each user based on defined parameters.By inputting specific data, such as foot measurements or user preferences, the algorithms can produce customized shoe designs tailored to individual needs and characteristics.Conversely, the second subcategory focuses on CAD design methods aimed at enhancing the final product.In this approach, factors such as fit, comfort, and safety are prioritized in the design process.Designers utilize CAD software to refine and optimize the shoe's geometry, ensuring that it meets the requirements and preferences of users while also maximizing functionality and usability.
The second category identified in the research focuses on the utilization of new technological tools within the footwear industry.This category encompasses a total of 38 research papers, which are further divided into 5 subcategories: 3D printing, 3D scanning, In more detail, and according to the literature research carried out, design is the first step to create a shoe, or a part of it.The way to design its geometry can be performed either through computational design or traditional CAD.The second step involves new digital production technologies.Three-dimensional printing and 3D knitting contribute to the main creation of the 3D form.Three-dimensional scanning with reverse engineering provides the ability to digitize the 3D shape to form the basis for digitally modifying it.In addition, the contribution of virtual and augmented reality is now very decisive in displaying and promoting, especially in online shopping.Additionally, sensors as a technology have the potential to enhance digital media for their final results.At the same time, in the third step where the control is conducted, data collection can be accomplished either through sensors or mechanical controls and through virtual or real tests.The resulting outcomes, in turn, lead to the approval or redefinition of the design or construction parameters.In the final step, the emerging market trend places the consumer-user at the center.This human-centered model results in the production of footwear products that perfectly suit the needs, characteristics, and personal preferences of each user.However, to achieve this, appropriate cooperation between the new technologies belonging to the previous steps is required.

Summary of Key Research Areas Depicted
The first category of research tasks focuses on the design of various parts of the shoe or the shoe's overall geometry.This category encompasses a total of 18 research papers, with 12 based on parametric design methods and 6 utilizing more traditional CAD design approaches.In the first subcategory, which centers on parametric design, algorithms play a key role in product design.These algorithms are programmed to generate personalized geometry for each user based on defined parameters.By inputting specific data, such as foot measurements or user preferences, the algorithms can produce customized shoe designs tailored to individual needs and characteristics.Conversely, the second subcategory focuses on CAD design methods aimed at enhancing the final product.In this approach, factors such as fit, comfort, and safety are prioritized in the design process.Designers utilize CAD software to refine and optimize the shoe's geometry, ensuring that it meets the requirements and preferences of users while also maximizing functionality and usability.
The second category identified in the research focuses on the utilization of new technological tools within the footwear industry.This category encompasses a total of 38 research papers, which are further divided into 5 subcategories: 3D printing, 3D scanning, 3D knitting, augmented reality-virtual reality, and sensors.The 3D printing subcategory highlights the contribution of 3D printing technology to the design and manufacturing phases of footwear.Through techniques such as fused deposition modeling, new geometries can be created to produce personalized shoes.The selection of suitable materials further optimizes shoe components.The 3D scanning subcategory explores the benefits of 3D scanning in footwear design.By capturing measurements and creating 3D models of users' feet, designers gain immediate insights for crafting personalized footwear.The 3D knitting subcategory introduces innovative technological tools such as 3D knitting, which revolutionizes the production process of footwear.By enabling the creation of complex shapes and materials, 3D knitting offers new possibilities and solutions while also reducing time and costs.Augmented Reality-Virtual Reality (AR/VR) technologies are combined in this subcategory to enhance the footwear design experience.These tools enable simulations and virtual interactions, allowing users to explore different environments and products.Virtual try-on experiences offer users a unique purchasing journey.Finally, the sensors subcategory focuses on the integration of sensors into footwear to monitor the user's gait.By collecting data on foot movements and performance, these sensors contribute to improving footwear functionality and user experience.
The third category of research work focuses on control simulation methods throughout the design and manufacturing stages of footwear.This category comprises twenty-nine research papers and is divided into two subcategories: Finite Element Analysis (FEA) and other control methods.The FEA subcategory includes thirteen research papers that utilize FEA for virtual experimental tests.These tests provide insights into the mechanical behaviors of footwear and its components.Factors such as materials, sole thickness, and plantar pressure points are analyzed to create functional shoes with optimized designs.The second subcategory of other control methods encompasses sixteen research papers that explore various control methods beyond FEA.These methods are employed to test footwear products and collect essential information for potential corrections and optimization of design and construction.These methods may include experimental tests and simulations aimed at improving footwear functionality and performance.
The fourth category of research work identified in the review concerns the targeted consumer groups within the footwear industry.This category comprises twenty-two research papers, categorized into two subcategories: professional and medical.The profes-sional subcategory includes twelve research papers that focus on adapting the geometry and characteristics of shoes, as well as their individual parts, to meet the specific needs of different user groups.Research in this subcategory addresses various sectors such as sports, work, and gender-specific shoes.The aim is to design shoes that address specific problems encountered by users in these contexts, ultimately improving user experience and performance.The second subcategory related to medical consists of ten research papers that prioritize user safety, particularly among vulnerable groups.Studies within this subcategory focus on designing specialized shoes for individuals with medical conditions such as diabetes, vision impairments, and the elderly.These shoes are tailored to minimize the risk of accidents and injuries in daily life, thereby enhancing the overall quality of life for these vulnerable groups.Improving the design of shoes for these specific demographics can significantly benefit their well-being and mobility.
At the conclusion of each analysis for every category, a graph was included (Figures 4-7), which depicted the basic category along with its respective subcategories, along with some related keywords.The primary objective of including these keywords was to offer concise and targeted descriptions of the main themes observed in the specific research.By identifying these keywords as 'trends', researchers can derive conclusions about potential directions for a more comprehensive approach to footwear.Additionally, Figure 9 illustrates the correlation between the number of trends and the number of research publications referenced in each category.The insights gained from this correlation could yield valuable insights into the current state of research.were prominently featured in the 3D scanning, Finite Element Analysis, and professional subcategories.
The trend of "Mass Production", extending beyond the 3D printing subcategory, was associated with computational design, professional, and medical subcategories."Adaptability" and "Identity" trends exhibited nearly identical prevalence across all categories."Visualization" and "Interaction" appeared the least frequently, particularly within their respective subcategories.The "Personalization" trend emerged as the most prevalent among research studies, followed closely by "Testing" and "Optimization".Interestingly, the "Personalization" trend was particularly prominent in the categories of Digital Manufacturing Technologies and Target Group.Conversely, "Testing" and "Optimization" were predominantly observed in the Simulation Control Methods category."Measurements" and "Needs" trends were prominently featured in the 3D scanning, Finite Element Analysis, and professional subcategories.
The trend of "Mass Production", extending beyond the 3D printing subcategory, was associated with computational design, professional, and medical subcategories."Adaptability" and "Identity" trends exhibited nearly identical prevalence across all categories."Visualization" and "Interaction" appeared the least frequently, particularly within their respective subcategories.
Figure 10 illustrates the distribution of the results, categorizing trends into three priority levels based on the number of occurrences.In detail, level 1 contains the set of trends that appear with the highest frequency in all articles.Level 2 includes trends that occur with slightly less frequency.Finally, level 3 includes the trends with minimum frequency.The above hypothesis formed the basis for the categorization of the three classes (level 1, 2, 3).Trends with values ranging from 0 to 15 are classified in the third and lowest level, those with values from 16 to 30 are placed in the second level, and those with values from 31 to 45 are in the highest level.Based on the internal elements from Figures 4-7, including their trends and number of occurrences across the literature survey, the categorization of Figure 10 was derived.According to the evidence from Figure 10, there are many opportunities for future review in the footwear industry.The trends identified in the analysis could potentially be integrated into other categories or subcategories, thus strengthening the research fields.In addition, focusing on trends with lower levels of hierarchy could lead to the emergence of new studies in areas that are either underexplored in the footwear sector or represent emerging trends in the industry.For instance, with the increasing adoption of algorithmic design by designers, more intricate and complex forms could be generated, particularly suitable for production via 3D printing technology.Moreover, by leveraging 3D scanning to digitize foot geometries, researchers can create highly accurate 3D models, which can then serve as a foundation for developing advanced control methods to optimize footwear products.Furthermore, the trend towards personalized footwear, which was identified as a predominant trend in most research studies, is likely to continue growing, indicating a significant area of focus for future research endeavors.

Conclusions
As already mentioned, the main objectives of the article are to document and clarify the main areas for (1) designing footwear with new technologies, (2) manufacturing footwear with new technologies, (3) controlling footwear with new technologies, and (4) personalizing footwear to each user with new technologies.For this reason, the research review conducted in the footwear design and manufacturing field identified four main directions: Design (De), Digital Manufacturing Technologies (Di Ma T), Simulation Control Methods (Si Co M), and Target Group (Tar G), each with corresponding subcategories.Through this comprehensive review, it became clear that there is a growing need for further research and engagement in personalized shoe design, particularly when combined with emerging technologies.In recent years, there has been an increasing demand for companies to produce footwear that not only exhibits superior quality, aesthetics, ergonomics, and functionality but also caters to the individual preferences and requirements of each customer.This requires shorter production times and reduced production costs.
In this particular article, an attempt was made to highlight the main trends that dominate the footwear industry.The above approach was based on the characteristics of new technologies and the possibilities they can offer (in design, manufacture, control, and to Based on the internal elements from Figures 4-7, including their trends and number of occurrences across the literature survey, the categorization of Figure 10 was derived.According to the evidence from Figure 10, there are many opportunities for future review in the footwear industry.The trends identified in the analysis could potentially be integrated into other categories or subcategories, thus strengthening the research fields.In addition, focusing on trends with lower levels of hierarchy could lead to the emergence of new studies in areas that are either underexplored in the footwear sector or represent emerging trends in the industry.For instance, with the increasing adoption of algorithmic design by designers, more intricate and complex forms could be generated, particularly suitable for production via 3D printing technology.Moreover, by leveraging 3D scanning to digitize foot geometries, researchers can create highly accurate 3D models, which can then serve as a foundation for developing advanced control methods to optimize footwear products.Furthermore, the trend towards personalized footwear, which was identified as a predominant trend in most research studies, is likely to continue growing, indicating a significant area of focus for future research endeavors.

Conclusions
As already mentioned, the main objectives of the article are to document and clarify the main areas for (1) designing footwear with new technologies, (2) manufacturing footwear with new technologies, (3) controlling footwear with new technologies, and (4) personalizing footwear to each user with new technologies.For this reason, the research review conducted in the footwear design and manufacturing field identified four main directions: Design (De), Digital Manufacturing Technologies (Di Ma T), Simulation Control Methods (Si Co M), and Target Group (Tar G), each with corresponding subcategories.Through this comprehensive review, it became clear that there is a growing need for further research and engagement in personalized shoe design, particularly when combined with emerging technologies.In recent years, there has been an increasing demand for companies to produce footwear that not only exhibits superior quality, aesthetics, ergonomics, and functionality but also caters to the individual preferences and requirements of each customer.This requires shorter production times and reduced production costs.
In this particular article, an attempt was made to highlight the main trends that dominate the footwear industry.The above approach was based on the characteristics of new technologies and the possibilities they can offer (in design, manufacture, control, and to the consumer).However, limiting the category to the footwear industry could be the basis for exploiting the main areas analyzed above in other sectors of the industry, for example, in furniture, clothes, and packaging.A key aspect of this new approach is the active involvement of users in the design process.By actively participating in the design process, designers can gain deeper insights into the unique needs and preferences of each user, allowing them to create products that truly meet their requirements.End users play a crucial role in shaping the design process, and their feedback and input are invaluable throughout the design journey.To achieve these goals, it is essential to make use of technology effectively.The use and development of technology offer designers the necessary tools and capabilities to create more efficient and customized designs.As part of future work, the authors intend to focus on utilizing parametric design tools to create personalized footwear products.By employing appropriate design software and leveraging modern technological tools, it is possible to develop customized products tailored to the preferences and needs of individual users.Additionally, conducting research to select suitable materials can further optimize the final product, ensuring it meets the highest standards of quality and functionality.

Figure 2
Figure2illustrates the primary research categories along with the respective number of scientific publications classified within each category.

Figure 2
Figure2illustrates the primary research categories along with the respective number of scientific publications classified within each category.

Figure 2
Figure2illustrates the primary research categories along with the respective number of scientific publications classified within each category.

Figure 3 .
Figure 3.The division of research based on the category and the year of their publication.

Figure 3 .
Figure 3.The division of research based on the category and the year of their publication.

Figure 4 .
Figure 4.The classification related to design category.

Figure 4 .
Figure 4.The classification related to design category.

4 .
Virtual and Augmented Reality (VR and AR)

28 Figure 5 .
Figure 5.The categorization of digital manufacturing technologies.

Figure 5 .
Figure 5.The categorization of digital manufacturing technologies.

Figure 6 .
Figure 6.The classification related to simulation control methods.Figure 6.The classification related to simulation control methods.

Figure 6 .
Figure 6.The classification related to simulation control methods.Figure 6.The classification related to simulation control methods.

Figure 7 .
Figure 7.The classification related to the target group category.

Figure 7 .
Figure 7.The classification related to the target group category.

Figure 8 .
Figure 8.The relationship of knowledge graph.

Figure 8 .
Figure 8.The relationship of knowledge graph.

Figure 9 .
Figure 9.The classification of the categories with the resulting trends.

Figure 10
Figure 10 illustrates the distribution of the results, categorizing trends into three priority levels based on the number of occurrences.In detail, level 1 contains the set of trends that appear with the highest frequency in all articles.Level 2 includes trends that occur with slightly less frequency.Finally, level 3 includes the trends with minimum frequency.The above hypothesis formed the basis for the categorization of the three classes (level 1, 2, 3).Trends with values ranging from 0 to 15 are classified in the third and lowest level, those with values from 16 to 30 are placed in the second level, and those with values from 31 to 45 are in the highest level.The third level includes the trends Algorithm, Injuries, Visualization, and Interaction.Moving up to the second level, the trends are Digital Presentation, Mass Production, Com-

Figure 9 .
Figure 9.The classification of the categories with the resulting trends.

Figure 10 .
Figure 10.Prioritization of trends.The third level includes the trends Algorithm, Injuries, Visualization, and Interaction.Moving up to the second level, the trends are Digital Presentation, Mass Production, Complex Shapes, Motion, Mechanical Behavior, Identity, and Safety.At the highest level are the trends Optimization, Design Software, Measurements, Experimental Control, Data Collection, Testing, Personalization, Adaptability, and Needs.It is worth noting that the maximum value a trend could attain is 106, which represents the total number of research papers.Adjustments to the level intervals would be made if trend values varied across different indications.Based on the internal elements from Figures4-7, including their trends and number of occurrences across the literature survey, the categorization of Figure10was derived.According to the evidence from Figure10, there are many opportunities for future review in the footwear industry.The trends identified in the analysis could potentially be integrated into other categories or subcategories, thus strengthening the research fields.In addition, focusing on trends with lower levels of hierarchy could lead to the emergence of new studies in areas that are either underexplored in the footwear sector or represent emerging trends in the industry.For instance, with the increasing adoption of algorithmic design by designers, more intricate and complex forms could be generated, particularly suitable for production via 3D printing technology.Moreover, by leveraging 3D scanning to digitize foot geometries, researchers can create highly accurate 3D models, which can then serve as a foundation for developing advanced control methods to optimize footwear products.Furthermore, the trend towards personalized footwear, which was identified as a predominant trend in most research studies, is likely to continue growing, indicating a significant area of focus for future research endeavors.

Table 1 .
Names, acronyms, and number of categorized research papers.

Table 2 .
Research work according to the aforementioned directions.