2.1. Design culture

Fisher (Reference Fisher2000) was one of the early designers to use the phrase “design culture.” He regarded culture as a conservative force that could resist the rapid shifts and dramatic upheavals of the marketplace. Julier (Reference Julier2006) viewed design culture as an academic discipline that has always existed as a process, a context-informed practice, a kind of organization or attitude, an agency and a pervasive but differentiated value. However, Julier also pointed out that design culture should therefore seek to understand and properly manage the relationships between designers, production and consumption and establish how to materialize these relationships through professional design practices in production and consumption. Atkinson (Reference Atkinson2015) argued that according to Julier’s assertion, the notion of “good design” and “bad design” should be conceptualized less in terms of artifact form and more in terms of the relationship between designer, producer and consumer. With the economic turn in sociology, a new interpretation of design culture is offered by Julier (Reference Julier2013), suggesting it is a state of being resulting from actions generated from circumstances. In addition, he also regarded design culture not only as a product but also as a description of the transformation from design into wider social and economic processes existing within neoliberalism. According to Manzini (Reference Manzini2016), design culture is the carrier for design experts and can be the original source of innovation for these experts. Therefore, he defines design culture as the “meaningful context” in which new projects are conceived and developed – including knowledge, values, visions and quality criteria that emerge from the tangle of conversations occurring during the design process across various arenas. Recently, “Design culturology” has been proposed by Chai & Zou (Reference Chai and Zou2024); the connotation of design culture has been further expanded.

In general, design culture research has sought to interpret, from both disciplinary and theoretical perspectives, how both tangible and intangible designs are related to culture, society, circumstances, the market, designers and consumers. The evolution of the “design culture” theory has shifted from being seen as a conservative force in the marketplace to a multifaceted concept encompassing academic discipline, social and economic transformation and a meaningful context for innovation; this concept has recently been expanded through the proposal of “Design culturology.”

2.2. Culture-centered/oriented design

Shen et al. (Reference Shen, Woolley and Prior2006) established the culture-centered design (CCD) system and proposed the culture-centered design process in the field of user interface design. Researchers believe that a favorable interface design must recognize and value its cultural context, and issues such as meaning and metaphors play a critical role in the design of user interfaces (Bourges-Waldegg & Scrivener Reference Bourges-Waldegg and Scrivener1998). Moalosi, Popovic & Hickling-Hudson (Reference Moalosi, Popovic and Hickling-Hudson2010) integrated three aspects: factors in the user’s domain, designer’s domain and product domain to construct a culture-oriented design model, which enables designed products to meet functional requirements, users’ aspirations, emotions, aesthetics and socio-cultural needs. According to Veer (Reference Veer2011), the cultures of design clients and users must be taken into account during the design process; culture-centered design requires designers to have a practical understanding of cultural aesthetics, languages and values. Heimgärtner (Reference Heimgärtner2013) argued that culture-centered design must consider basic cultural differences when incorporating cultural elements into human–machine interaction. Gozde (Reference Gozde2013) developed a culture-centered design process to help designers effectively create designs for cultures other than their own. To accommodate the needs of users from different cultural backgrounds, Asano & Yamazaki (Reference Asano and Yamazaki2014) used culture-centered design to quickly identify a user’s culture and proposed that cultural differences can be recognized by designers through observation, analysis and design methods. Then Parmaxi & Zaphiris (Reference Parmaxi and Zaphiris2016) proposed that culture-centered design and internationalization of user interfaces are key areas for universal access in information society; related studies emphasized the need to integrate cultural aspects into interface design. Clark & Yamazaki (Reference Clark and Yamazaki2019) stated that culture-centered design – enabled by digital transformation – situated within human-centered design embraces variations in products, services and experiences to accommodate the cultures served by organizations. Li et al. (Reference Li, Sun and Zhang2007) pointed out that rapid global development of information communication technologies has led standardized interface applications to pose usability challenges for multicultural users; these cultural issues provide valuable implications for digital product designers regarding approaches to usability testing methods.

Overall, culture-centered design is related to human-centered design and user-centered design (Gasson Reference Gasson2003). It is regarded as a focused version of human-centered design and can make it possible to design for cultures (Clark & Yamazaki Reference Clark and Yamazaki2019). Culture-centered design research emphasizes the cultural elements and differences of users in order to provide a reference for the design of intangible products, such as human-machine interface design and interaction design. Existing studies gradually establish culture-centered design as a paradigm that coordinates technological functionality with cultural inclusivity, reshaping how designers integrate cultural awareness into digital products, services and user experiences. Culture-centered design fundamentally transforms interface design and interaction design by systematically integrating cultural contexts, symbols and values into the design process, ensuring that products and services meet both functional requirements and the socio-cultural needs of diverse users while addressing globalization-driven usability challenges.

2.3. Cultural product design

Leong & Clark (Reference Leong and Clark2003) developed a framework that can significantly distinguish research cultural objects at three levels. Lin (Reference Lin2007), Lin et al. (Reference Lin, Xian, Chang, Chan, Hsieh and Huang2007), Lin, Cheng & Sun (Reference Lin, Cheng and Sun2007) highlighted the significance of culture in design and predicted cross-cultural design as a key future criterion. They proposed the three layers and levels of cultural objects and design features, developing a cultural product design model to systematically transform cultural features into products that meet the demands of contemporary consumers while preserving cultural value. Following research on how to integrate traditional cultural elements into product design in order to better satisfy consumers, Chai et al. (Reference Chai, Bao, Sun and Cao2015) suggested that consumers prefer cultural products with modern design elements. Moreover, Chai et al. (Reference Chai, Shen, Bao and Sun2018) proposed an intangible culture-oriented product design approach. This verified the feasibility of the Doctrine of the Mean with regard to product design and showed designers a new way to approach the creation of cultural products. From the perspective of kyosei (co-living), Nguyen (Reference Nguyen2016) interpreted the development and features of Japanese culture and design practice, proposing some controversial methods in design. Çakmakçıoğlu (Reference Çakmakçıoğlu2017) proposed a method for transferring cultural elements into future designs within the scope of product design, suggesting that culturally influenced product designs would become increasingly abstract due to new techniques. Shin & Westland (Reference Shin and Westland2017) explored principles, strategies and processes for transforming traditional culture into digital design programs and developed a traditional digital cultural design tool, which has been used to assist in traditional Korean bojagi textile design. Recently, Han, Shi & Shi (Reference Han, Shi and Shi2022) pointed out that the main aspect of culturally creative products is incorporating cultural features into new products; thus, obtaining creative- and culture-based products is what this article refers to as a type of cultural product.

Overall, these studies emphasize the importance of integrating cultural elements into product design, illustrating how cultural features can be transformed into products that resonate with contemporary users’ cultural identities. Cultural product design primarily focuses on how to extract cultural elements and transform cultural features, as well as how to embed them in tangible products such as buildings, furniture and textiles so that these products are endowed with culturally specific themes and are therefore culturally recognizable to users.

3.1. Framework of cultural carriers

To seek a more structured framework to organize these features, the discussion on the levels of culture has been explored. Liu (Reference Liu1998) classified culture into material culture and spiritual culture, and Oswell (Reference Oswell2006) argues that culture consists of both non-material and material elements. According to Yang (Reference Yang1998), culture can be divided into physical, mid-level and metaphysical levels. For Leong & Clark (Reference Leong and Clark2003), the three levels of culture are the outer “tangible” level, the mid “behavioral” level and the inner “intangible” level. Similarly, Lin (Reference Lin2007) suggests that the design features of cultural products can be divided into outer “tangible,” mid “behavioral,” and inner “intangible” levels. Culture has different layers and corresponds to different levels: the spiritual/ideal layer, which corresponds to the inner level, refers to implicit and intangible concepts and awareness such as psychological structure, philosophy and religion; the social/behavior layer, which corresponds to the middle level, refers to visible but intangible immaterial carriers such as behaviors and habits, rules and regulations and traditional dialects; and the physical/material layer, which corresponds to the outer level, refers to visible and tangible material carriers such as landscapes, architectural relics, animals and plants.

In this article, the framework of cultural carriers is proposed as shown in Table 1 based on the research on cultural classification mentioned above, which covers most of the common tangible material and intangible immaterial cultural carriers and groups them into the following three levels:

• • Level 1. Broad cultural carriers at each of the three layers. Combining the three levels of culture theory (Leong & Clark Reference Leong and Clark2003; Lin Reference Lin2007), cultural carriers at Level 1 can be divided into three categories: (C ₁) spiritual/ideal layer, primarily corresponding to the inner level and conceptual design level; (C ₂) social/behavioral layer, mainly aligned with the middle level and behavioral design level and (C ₃) physical/material layer, principally mapped to the outer level and visual design level. These cultural carriers at Level 1 constitute a macroscopic classification framework and do not encompass specific cultural manifestations.

• • Level 2. Subdivision of the broad cultural carriers. Based on research on regional cultural composition (Xu, Wang & Xiang Reference Xu, Wang and Xiang2014; Liang et al. Reference Liang, Liu, Xiang, Zhi, Bu and He2023), we have currently subdivided cultural carriers at Level 1 as follows: Cultural carriers belonging to (C ₁) spiritual/ideal layer have been clearly divided into four subdivisions at Level 2; cultural carriers belonging to (C ₂) social/behavioral layer have been clearly divided into three subdivisions at Level 2 and cultural carriers belonging to (C ₃) physical/material layer have been clearly divided into four subdivisions at Level 2. These subdivided cultural carriers are not currently comprehensive and may be further expanded. While cultural carriers belonging to the spiritual/ideal layer at Level 2 have been explicitly defined, those belonging to the social/behavioral and physical/material layers still do not encompass specific cultural manifestations.

• • Level 3. Specific cultural carriers. Building on the classification of regional cultural factors (Xu et al. Reference Xu, Wang and Xiang2014; Liang et al. Reference Liang, Liu, Xiang, Zhi, Bu and He2023) and incorporating practical implementation requirements, the subdivided cultural carriers belonging to the social/behavioral and physical/material layers at Level 2 have been further categorized as follows at Level 3: Cultural carriers belonging to (C ₂₁) regional folk customs have been clearly divided into eight specific cultural carriers; cultural carriers belonging to (C ₂₂) regional systems have been clearly divided into three specific cultural carriers; cultural carriers belonging to (C₂₃) relations between different ethnic groups have been clearly divided into three specific cultural carriers; cultural carriers belonging to (C ₃₁) ecological materials have been clearly divided into five specific cultural carriers; cultural carriers belonging to (C ₃₂) historical remains have been clearly divided into seven specific cultural carriers; cultural carriers belonging to (C ₃₃) landmarks have been clearly divided into four specific cultural carriers; cultural carriers belonging to(C ₃₄) cultural and creative products have been clearly divided into four specific cultural carriers. Similarly, specific cultural carriers belonging to the social/behavioral and physical/material layers at Level 3 are also not complete and need further expansion. However, due to the insufficient clarity of cultural carriers within the spiritual/ideal layer, the specific cultural carriers at Level 3 are not further divided in this framework.

Table 1. Framework of composition and division of cultural carriers

3.2. Extraction and translation method of culture

To further describe how to provide a systematic and operational method after defining the composition and division of cultural carriers, an extraction and translation model of culture is constructed, and the extraction and transformation paths of cultural elements are explained, respectively, from the ordered association framework of cultural carriers, cultural elements and cultural features. The extraction and transformation methods of culture at different levels are then elaborated through the conceptual design level, behavioral design level and visual design level within the model’s architecture.

3.2.1. The model

Selecting suitable cultural elements from the diversified cultural carriers could be dazzling. To avoid the simple and direct replication of cultural factors, designers need to carefully identify, extract and translate culture into design elements and achieve a balance between identity and abstraction. This sub-subsection describes a model to guide designers in extracting and translating culture. However, only by transforming cultural elements into cultural features can they be effectively integrated into the design scheme and convey the cultural connotations of the target region with the help of that design scheme.

According to ISO (2015), “product” is defined as “the output of an organization which can be produced without any transaction taking place between the organization and the consumer.” It lists “product” and “service” independently to emphasize the tangibility of products and the intangibility of services. In terms of the tangibility of products and the different layers of culture, Lin (Reference Lin2007) divides the properties of cultural products into: (1) An inner, “intangible” level, which includes distinctiveness, storytelling, emotionality and cultural features; these properties are predominantly expressed in the conceptual design level (which belongs to reflective design). (2) A mid, “behavioral” level, which includes function, usability, operation and user satisfaction; these properties are predominantly expressed in the behavioral design level. (3) An outer, “tangible” level, which includes appearance, color, material, line and texture; these properties are predominantly expressed in the visual design level (which belongs to visceral design). In addition, Norman (Reference Norman2004) presents three levels of design: visceral level focuses on beauty and safety while satisfying appearance; behavioral level focuses on functionality and use/operation; reflective level focuses on impression and meaning.

“Translation” has long been a crucial yet equivocal concept in the human sciences, intrinsically entwined with the equally ambiguous notion of “culture” in addressing fundamental problems of understanding and interpretation (Ødemark Reference Ødemark2018). Cultural translation involves understanding ourselves and developing ourselves by interacting with others who are different (Kroneman Reference Kroneman2019). Meanwhile, design culture primarily explains how tangible and intangible designs relate to culture, society, circumstances, markets, designers and consumers, serving as a meaningful context for innovation. In practice, the extraction and translation of culture in product design remain ambiguous. To address this gap, we synthesize the aforementioned perspectives on cultural translation and design culture, proposing a method for the extraction and transformation of cultural elements in product design. This method emphasizes that the extraction and translation process should systematically incorporate factors such as culture, society, context, markets and consumers associated with the target product(s). It fully explores cultural elements and embodies meaningful contexts within the innovative design process, thereby interpreting and showcasing cultural features through the interaction between design solutions and users, enabling users to easily understand them. To further enhance cultural product design creativity, the extraction and translation model of culture is developed based on the three levels of conceptual design, behavioral design and visual design; see Figure 1.

Figure 1. Extraction and translation model of culture.

In this model, the elements can be obtained from the corresponding cultural carriers in Table 1. Cultural features refer to visible, understandable, or operable special features with cultural symbolic significance obtained by further summarizing the cultural carriers, so as to integrate these features into the new cultural product schemes via innovative design and be perceived and understood through interaction with the users. The design work after fully constructing the cultural carriers database for the target region according to Table 1 includes: (1) Deriving conceptual cultural elements from the extraction of the spiritual/ideal cultural carriers, and then further deriving the conceptual cultural features applicable to the product design schemes from the translation of the conceptual cultural elements, which belong to the tasks of the conceptual design level; (2) deriving behavioral cultural elements from the extraction in social/behavioral cultural carriers, and then further deriving the behavioral cultural features applicable to product design schemes from the translation of behavioral cultural elements, which belong to the tasks of behavioral design level; (3) Deriving conceptual cultural elements from the extraction in the physical/material cultural carriers, and then further deriving the visual cultural features applicable to the product design schemes from the translation of the visual cultural elements, which belong to the tasks of the visual design level.

3.3. The strategy

The cultural elements at the conceptual design level, the behavioral design level and the visual design level are reflections of the spiritual/ideal cultural carriers, the social/behavioral cultural carriers and the physical/material cultural carriers. In the design process, cultural elements should first be extracted and translated at the conceptual design level to set the basic cultural tone. Based on this, behavioral cultural elements and/or visual cultural elements can be further extracted at the behavioral design level and visual design level. All of these elements should be used to construct a database of cultural features. It is important to note that in practice, due to the diversity of product functions and use behaviors, not all products are imbued with relevant cultural elements at either the conceptual or behavioral design levels. As shown in Figure 1, the strategy for using the extraction and translation model of culture works as follows:

• • The identified conceptual cultural elements should guide the extraction of behavioral and visual cultural elements.

• • The identified behavioral and visual cultural features should, in turn, reflect the conceptual cultural features.

• • These three should have the same or similar cultural themes.

3.4. Cultural product design process

Lin (Reference Lin2007), Lin et al. (Reference Lin, Xian, Chang, Chan, Hsieh and Huang2007), Lin, Cheng & Sun (Reference Lin, Cheng and Sun2007) developed a cultural product design model to systematically transform cultural features into products (e.g., cups, pots and bags) and outlined a four-stage cultural design process. Chai et al. (Reference Chai, Shen, Bao and Sun2018) proposed a design process for infusing products (e.g., chairs) with Confucian culture and formalized a four-stage cultural design framework. To better realize the incorporation of culture into products, especially modern large and complex products, a detailed cultural product design process is proposed with consideration of how to embed the proposed model in the whole design process (Figure 2); its main stages are as follows:

• • Stage 1: Establish the territorial scope (geographical space) for the target product. This stage requires designers to make determinations based on the specific product being designed, explicitly clarifying the territorial scope of product usage, the demographic composition of target users and any potential cultural preferences or taboos inherent to the user group. A precise definition at this stage enables more accurate identification of matching regional cultural carriers during subsequent cultural carrier identification processes.

• • Stage 2: Identify typical representative tangible material and intangible immaterial cultural carriers within the territorial scope of product usage. This stage necessitates that designers systematically investigate cultural carriers related to the target product, employing the Framework of Composition and Division of Cultural Carriers (see Table 1) to document representative carriers across three levels: spiritual/ideal layer, social/behavioral layer and physical/material layer. All identified cultural carriers within the territorial scope of product usage are cataloged within this tripartite structure, establishing a proprietary cultural carrier database. Comprehensive documentation during this stage ensures the availability of sufficient foundational materials for subsequent cultural element extraction processes.

• • Stage 3: Extract conceptual, behavioral and visual cultural elements. This stage requires designers to filter the cultural carrier database built in the previous stage according to the Extraction and Translation Model of Culture (Figure 1), extract conceptual, behavioral and visual cultural elements at the conceptual design, behavioral design and visual design levels, and further build a cultural element database. A comprehensive and detailed extraction of the cultural elements involved in the target product will help provide rich and necessary materials for the next stage of translating cultural features.

• • Stage 4: Translate conceptual, behavioral and visual cultural features. This stage requires designers to select cultural elements suitable for the target product from the cultural element database built in the previous stage, combine them with the Extraction and Translation Model of Culture (Figure 1), and construct applicable cultural features for the target product, such as themes, usage behaviors, form/pattern sets, color sets, or material libraries. The cultural features generated in this stage should be easily perceived and recognized by the public through visual channels. This process is key to endowing the design solution with cultural features in the next stage.

• • Stage 5: Apply cultural features in target product design. This stage requires designers to determine in detail the technical, design-related and standard constraints of the target product. During the design process, it is critical to comprehensively balance the potential impact of these constraints on the incorporation of conceptual, behavioral and/or visual cultural features. In addition, this stage requires designing as many design schemes with regional cultural features as possible to provide evaluation materials for the next stage.

• • Stage 6: Conduct a survey to evaluate the cultural identity of the design schemes. This stage requires designers to search for as many adults and design professionals as possible who can represent potential future users of the target product to subjectively evaluate the design schemes. By using convenient and effective methods such as smartphone questionnaires or on-site questionnaires, the cultural significance of the design schemes can be quantitatively evaluated. Based on the evaluation feedback results, it is determined whether the design schemes have obvious cultural features, which can be included in the design scheme library.

Figure 2. Cultural product design process.

4.1. Identification and extraction

The territorial scope for the case study is Thailand (Stage 1). Data regarding typical Thai cultural carriers were acquired from the Internet, literature research and field surveys (Stage 2). Once the data had been sorted, conceptual cultural elements related to the design of the inter-city train were proposed. These included “Buddhist culture” (C ₁₂) and “Thailand’s totem culture” (C ₁₃). From the acquired cultural carriers, the White elephant (C ₃₁₃) and Lophura diardi (Siamese Fireback Pheasant) (C ₃₁₃) were chosen as cultural elements. The former was selected because Thailand is known as “the land of the White elephant” (Bacon Reference Bacon2010), while the latter is the country’s national bird (Ramel Reference Ramel2023). Both animals were chosen to be the visual cultural elements for the train’s exterior design. Based on conceptual cultural elements of Buddhist culture and the Grand palace (C ₃₃₁), various Thai temples (C ₃₂₁), ancient Thai national dress (C ₃₂₃) and the country’s most famous railway station landmark, where a photo of Princess Sirindhorn hangs (C ₃₃₁), were selected as visual cultural elements for the train’s interior design (Stage 3).

4.2. Translation

According to the White elephant and L. diardi prototypes, together with the head form of the inter-city train, the designers used a freehand drawing to extract basic styling lines that visually reflected the morphological features of the White elephant (Figure 3a) and L. diardi (Figure 3b). The designers then hand-copied recurring features of lotus patterns, fish tooth patterns and golden patterns from samples in the Grand Palace, temples, the railway station landmark and Thai national dress (He Reference He2012). In addition, a color set of these typical cultural elements, which were specifically distributed in color space, was constructed using a natural color system (Figure 3c) (Stage 4). However, the exterior and interior of the inter-city train did not correlate with user behavior at the social/behavioral layer; therefore, the designers failed to extract and translate suitable behavioral cultural elements and features for its design.

Figure 3. Translation of the suitable forms, patterns and colors for the Thailand inter-city train: (a) land of the White elephant; (b) national bird L. diardi and (c) the Grand Palace, temples, Thai national dress, railway station, etc.

4.3. Implementation

Based on the acquired forms, patterns and colors, as well as in accordance with the technical characteristics of the train, design constraints and standards and industrial specifications (Xiang et al. Reference Xiang, Zhi, Huang, Kang, Li, Gao and Li2019), several exterior and interior design schemes were developed via computer-aided design in Figure 4. Exterior design 1 (Figure 4a), the White elephant (Figure 3a) was selected as the visual cultural element for the design. The form of the White elephant was given full consideration and infused into both the train’s exterior shape and coating. Exterior design 2 (Figure 4b), L. diardi (Figure 3b) was selected as the visual cultural element for the design. The form of this bird was given full consideration and infused into both its exterior shape and coating. As compared to Exterior design 1, Exterior design 2 is more abstract.

Figure 4. Exterior and interior design schemes for Thailand’s inter-city train: (a) exterior design 1; (b) exterior design 2; (c) end space; (d) business coach and (e) economy coach.

The commonly used lotus pattern, fish tooth pattern, golden pattern and colors in Figure 3c were infused into the interior design of the train, creating a series of interior design schemes for the end space (Figure 4c), business coach (Figure 4d) and economy coach (Figure 4e). Each of the design schemes was aimed at presenting the cultural features of Thailand (Stage 5).

4.4. Evaluation

With the development of the mobile Internet, WeChat^TM-based electronic surveys have become an important method as they are easy to implement and spread, and can collect extensive amounts of subjective feedback (Sun et al. Reference Sun, Zhu, Liang and Xu2016). To evaluate whether the above-mentioned design schemes were consistent with Thailand’s cultural features, a smartphone survey was designed on the network platform WJX.CN™ (Stage 6). The advantages of the Chi-square test include its robustness in handling data, ease of computation and the absence of assumptions regarding a specific data distribution (McHugh Reference McHugh2013). It has been demonstrated that Chi-square tests perform well in assessing the relevance of characteristics of design alternatives (Xie Reference Xie2023) and are particularly suitable for analyzing the qualitative nature of evaluation data for design schemes. Therefore, Chi-square tests were employed in this study to analyze the data and evaluate design schemes, as they are appropriate for testing the independence or association of parameters with score distributions (Franke, Ho & Christie Reference Franke, Ho and Christie2012).

The survey collected feedback from four groups of respondents: doctoral degree design students (G1, N = 37), master’s degree design students (G2, N = 38), bachelor’s degree design students (G3, N = 31) and a random sample of adults (G4, N = 95) to provide feedback on the design from multiple perspectives. Except for the G4 group, the respondents from the other three groups have a certain understanding of Cultural product design and the application of cultural carriers, cultural elements and cultural features in Thailand was fully explained in the experimental online questionnaire. Respondents were required to register online and use their smartphones to evaluate the design schemes according to the following options: “Reflects Thailand’s cultural features,” “Does not reflect Thailand’s cultural features,” or “Not sure if it reflects Thailand’s cultural features.” Each respondent had only one chance to make each choice. The survey and results can be viewed at https://tp.wjx.top/m/38615903.aspx (G1), https://tp.wjx.top/m/38611265.aspx (G2), https://tp.wjx.top/m/38611461.aspx (G3) and https://tp.wjx.top/m/41182601.aspx (G4) (Note: Please refer to the Supplementary material for the English versions of the four survey results). The survey results of the four groups are shown in Table 2. It can be concluded that:

• • Cultural feature significance of design schemes and recommended criteria for inclusion in the design scheme library. Overall, the four groups of survey feedback results show that the majority of respondents believe that the design schemes reflect Thailand’s cultural features. Among the 201 respondents, the percentages indicating that each design scheme “do not reflect Thailand’s cultural features” are as follows: exterior design 1 (Figure 4a): 6.47%; exterior design 2 (Figure 4b): 10.95%; end space (Figure 4c): 4.98%; business coach (Figure 4d): 4.48%; economy coach (Figure 4e): 3.48%. Conversely, the percentages indicating that each design scheme “Reflects Thailand’s cultural features” are as follows: exterior design 1: 72.14%; exterior design 2: 57.71%; end space: 82.09%; business coach: 80.60%; economy coach: 84.58%. When establishing criteria for inclusion in the design scheme library, we propose disregarding the proportion of respondents who selected “unsure whether it reflects Thailand’s cultural features.” It is recommended to comprehensively evaluate the proportions of respondents selecting both “does not reflect Thailand’s cultural features” and “reflects Thailand’s cultural features” for assessment. Specifically, the criteria suggest that the proportion of respondents selecting “reflects Thailand’s cultural features” should exceed 50%, while the proportion selecting “does not reflect Thailand’s cultural features” should ideally be maintained below 15%.

• • Cultural feature expression effectiveness of each design scheme. Based on the feedback data, the percentages of “Reflections of Thailand’s Cultural Features” selected in descending order for the five design schemes are as follows: economy coach (84.58%), end space (82.09%), business coach (80.60%), exterior design 1 (72.14%) and exterior design 2 (57.71%). According to chi-square tests, the results showed that the feedback on exterior design 1 and exterior design 2 was statistically significantly different (Χ² = 9.310, df = 2, p = 0.010), whereas the feedback on end space, business coach and economy coach showed no statistically significant differences. By analyzing the feedback data, it can be concluded that infusing concrete and visually perceivable cultural elements – such as lotus patterns, fish tooth patterns, golden motifs and colors – into the train’s interior design enhances the effectiveness of cultural feature expression and elicits a higher proportion of positive feedback. Conversely, cultural elements such as the White elephant and Lophura diardi, which are relatively abstract and less visually distinctive, may struggle to achieve high recognition in terms of cultural feature expression effectiveness, as evidenced by previous interior design schemes. Overall, while both exterior design and interior design of trains must adhere to technical constraints, standards and industry specifications, exterior design faces more complex limitations, thereby reducing design flexibility. As a result, the cultural feature expression effectiveness of exterior designs 1 and 2 is notably lower than that of the three interior schemes. The significant difference between exterior design 1 and exterior design 2 likely stems from the White elephant’s greater familiarity and visual recognizability compared to L. diardi when associating train head shapes with cultural elements. Therefore, visual cultural element(s) for the exterior design of trains should prioritize public familiarity and perceptibility.

• • Cultural features significance feedback from different respondents. According to Chi-Square tests, in terms of the comparison between exterior design 1 and exterior design 2, there was a statistically significant difference (Χ ² = 16.184, df = 2, P < 0.001) in whether the design reflects Thailand’s cultural features from the feedback of design professionals (G1 & G2 & G3, N = 106). However, from the perspective of a random sample of adults (G4, N = 95), Exterior design 1 is as good as exterior design 2. The design professionals and a random sample of adults have statistically significant different options on whether the design schemes successfully reflect Thailand’s cultural features. Analysis of potential reasons for these differences suggests two main factors: Compared to the random sample of adults, design professionals generally possess a deeper understanding of cultural and aesthetic principles. As a result, they adopt a more rigorous and cautious attitude when cognitively evaluating the cultural features reflected in products. These factors may explain why design professionals were more likely to select the “unsure whether it reflects Thailand’s cultural features” response option compared to the random sample of adults. Consequently, to gain approval from design professionals, the design process should strive to comprehensively incorporate conceptual, behavioral and/or visual cultural features. The random sample of adults primarily relied on visually conveyed information from the design schemes to make subjective judgments. Unlike design professionals, they tended to respond quickly with “yes” or “no.” Therefore, to secure their approval, designs should prioritize clarity and intuitiveness to emphasize visual cultural features.

Table 2. The survey results of the four groups for the schemes of the Thailand inter-city train

4.5. Summary

The three-layer framework proposed in this paper can guide designers in rapidly selecting cultural elements by searching for tangible and intangible cultural carriers once the target product’s usage region is established in design practice. To integrate regional culture into modern products, it is critical to manage the identification, translation and implementation of cultural features throughout the product design process. The cultural product design process proposes six stages for developing target products: identifying cultural carriers, extracting cultural elements, translating and applying regional cultures, followed by implementation and evaluation. The design case of the Thai inter-city train’s exterior and interior – completed following this cultural product design process – provides implementation examples demonstrating practical applications of this approach. Meanwhile, due to product diversity, technical characteristics, design constraints, standards and industrial specifications differ across product categories. To successfully apply acquired regional cultural elements to target product design, designers must thoroughly understand these constraints. Additionally, designers should identify carriers that are familiar and easily understandable to public audiences within target product domains; then extract and translate these into conceptual, behavioral, and/or visual cultural features. Through design implementation, they should showcase maximal visual cultural features in proposals. This approach may prove more effective for creating culturally connotative products, achieving broad public recognition.