## 3 Results and Discussion
### Discussion
Since persons with lower limb paralysis cannot maintain standing state on their own, it must be erected using an artificial standing holding device. The 3D scan should be performed in a state where there is no physical interference factor that unnecessarily obstructs the human body shape. For these two reasons, securing a database of human body shape for people with leg paralysis disorder can be achieved through a very long-term project over several years. In this study, a size system was developed using a database of normal persons due to the fact that it targets persons with subacute paralysis, which is the stage before sudden muscle contraction due to paralysis of the lower extremities, and the practical difficulty of securing the human body shape database of persons with paralysis of the lower extremities. In addition, the shape of the human body varies according to factors, such as country, adult-child, male-female, and so on. In this study, as the first step of the gradual study, the size system of 3 DP-pHRI was developed using the human body shape database for Korean male adults. A size system-based 3 DP-pHRI was developed and proposed as a new alternative to realize the body shape-fit without the 3D scanning process and template remodeling process in the 3D printing body-fit of the wearable robot. In the existing template remodeling-based 3D printing body fit, the 3D scanning of the human body shape of the wearer is indispensable. It is very cumbersome and complicated because a specially designed standing posture maintenance device must be used to 3D scan the human body shape of a person with a paralysis disorder, and falls may occur in some cases due to insufficient safety management. 3D scanning data is additionally required for post-processing. There is a variation in effort and time required according to the function of the 3D modeling program used in the remodeling process for 3D printing body shape fit based on template remodeling up to now. 3D modeling programs are divided into surface-based modeling and solid-based modeling. For 3D printing production, solid-based modeling that completely fills the interior is most suitable. Existing solid-based modeling programs include polygon-based 3D animation-only modeling programs (e.g., Maya, 3D Max, Blender, etc.) and parametric solid modeling programs (e.g., SOLIDWORKS, CATIA, Proe, etc.) used for product design. Since 3 DP-pHRI has an organic double-curve shape, it is difficult to use a parametric solid modeling program. Modeling program dedicated to 3D animation is advantageous for realizing an organic double-curved surface, and template remodeling can be implemented by utilizing some functions such as 'wrap geometry on a surface'. However, these programs have a disadvantage in that it is difficult to control dimensions such as the thickness or contour shape of a template based on parameters in the process of automatic deformation remodeling. As the shape complexity of the template increases, errors in automatic deformation remodeling increase. Therefore, it is considered that 3D printing body fit based on template remodeling is not yet a feasible alternative due to the difficulty of the 3D scanning of the human body shape of the paralyzed person and the still incomplete automatic transformation remodeling process. In this respect, the size system-based 3 DP-pHRI developed and proposed in this study is considered a more effective alternative compared to the existing template remodeling-based 3D printing body shape customization. However, research on the development of a dedicated platform that solves the difficulties of the 3D scanning process and that can fully implement the 3 DP-pHRI remodeling process automatically is valuable as the ultimate future research goal.