## 3 Results
### Analysis of Current Modular Design and Prosumer Methods
#### 3.1.2 Analysis of Modular Design Methods  
The relationship between modular design methods and the design phase in which each one is used is analyzed. In addition to locating each method in its phase of use, in Figure 2, we have used three colors to differentiate the essential, interesting and potential methods to achieve the objective set in this research. First, those methods that are considered essential to apply the modular design methodology because they are the basis of the other methods or because of the frequency of their use appear in red. In the case of developing a methodological model, the presence of these methods would ensure the correct application of modular design. Secondly, those methods considered interesting if they are adapted with small modifications to the objective of this research have been highlighted in yellow. Finally, those methods that can potentially be used for both modular design and prosumers at the same time have been highlighted in green.  
Figure 2 shows a total of 31 modular design methods that have been previously compiled in other review articles on this field [8; 20]. The methods presented are not the most relevant at a global level in the field of modular design but are the most present in the cited review articles. As can be seen, an absence of methods is detected in the phases of the identification of primary needs, preliminary design and distribution plan. However, some of the cited methods indirectly affect the distribution phase, although it is not their main objective. The same is not true for the preliminary design phase, where no method has been developed with the aim of being applied in the conceptualization of the product. Instead, most methods operate in the design development phase with an equitable presence between the detailed design and manufacturing planning phases. Finally, we also observe that the presence of methods in the consumption phase is limited, concluding that the end user can hardly take part in the transformation of their own products through modular design.  
Figure 2: Analysis of current modular design methods according to the phases of the process.  
Four essential methods to apply modular design are detected as they are the basis for the creation of other methods, such as Design Structure Matrix (DSM) or Modular Function Deployment (MFD) [19; 28]. This fact is also supported by the number of citations and year of publication of these methods. We observe that two of these aim to identify functional groups (feasibility study), while the other two seek the development of modules to modularize products (detailed design). On the other hand, most of the interesting and potential methods are located in the manufacturing planning phase. Three methods have been identified that could be of interest if they are adapted to other objectives or design phases [29; 30; 31]. Two of them are located in the planning for manufacturing phase, and their objectives include developing interchangeable accessories and creating modular products that are user-friendly for the customer. Both methods would be interesting if they evolved to be applied in the consumption phase by the end user. The other method identified is located in the consumer phase and focuses on the brand and sensory esthetics, but it could be of interest if the objective were also functional. Finally, three methods with potential use for prosumers have been detected that can improve their relationship with modular design through product variety, attention to consumer demand and the creation of product families [32; 33; 34].