## 2 The Model and Architecture of the Remote Prototyping System  
The functionality of the remote prototyping system ought to meet modern challenges and expectations of its target users. Hence, the prepared model should combine a wide range of functionality with intuitive operation, taking into account the scalability, as well as reliability and high security level. Unfortunately, models of design and production systems, which have been used so far, had referred to two classic approaches. The first one assumed that all necessary resources are located in one place and such a model had a centralized nature. In the second one, the distributed nature of resources was assumed, however, assuming their individual and independent character. Of course, the last decade hasbroadened the view on remote, distributed work in the form of the development and implementation of cloud computing models, but mainly all their implementations were related solely to \(\Pi\) systems. Yet the actual implementation of the Industry 4.0 concept [39] requires an unconventional view not only of local design and production resources in terms of their automation and computerization, but also requires breaking down barriers by recognizing that integrated infrastructure may not have geographical limitations. The principles of the RDRP presented in the introduction were the basis for the development of a new model and then an architecture for the integration of distributed resources with different characteristics and purposes. This approach is particularly important in the case of distance limitations, unusual events and natural disasters or even the epidemic state. The team has thereby adopted a new model that allows design and production without time and geographical limitations. The concept of this model is presented in Figure 2.  
The adopted model implies four main action stages and four functional areas supporting them. Separate action stages are correlated with the process of rapid prototyping and include:  
* Creation of a concept: This is the first stage, during which initial assumptions are made about the future solution, its functionality and technical parameters, as well as its intended purpose. * Creation of a digital model: Within this stage a digital model is developed using dedicated CAx applications. At this stage, the data concerning the modelled object should be initially verified. This allows for adjustments to be made to the initial assumptions obtained at the concept development stage. Any actions taken at this stage may save time and reduce the costs of future revisions. As for the incremental production, CAD/STL/RP numerical data is required for test models. Additionally, the choice of incremental method ought to be analyzed in terms of manufacturing process parameters, expected area of application (RP, RM, RT), and material selection. Development of numerical data can be divided into several stages. The first stage is to develop 3D geometry-CAD of the test model in the selected environment. Each 3D-CAD geometry creation software saves data with a selected software-specific file format, e.g., saving  
Figure 2: The adopted model of remote and distributed prototyping system. solid geometry in Autodesk Inventor occurs with the IPT format. However, other software on the market provides the ability to read as well as edit a file with a format other than the one dedicated for your chosen software. In many cases, however, to help multiple users working on a single test model, a file is saved in the standard ISO STEP data exchange format. The next stage is the processing of data into an incremental process. It involves superimposing a grid of triangles on the received solid models (tessellation or triangulation). With the use of 3D-CAD solid models as a base, the models with the format recognizable by software dedicated to the machine and incremental method need to be developed. The STL (Standard Triangulation Language) happens to be the most frequently used format so far.