## 2 The Model and Architecture of the Remote Prototyping System
Recording the geometry in the form of a triangular grid with the above mentioned formats. It allows for the next stage of data processing, which consists of transforming the geometry into a control program for the machine. This stage is performed with the use of dedicated or supporting software and includes cutting the model into layers and defining the manufacturing parameters of the process, and then converting it into G-code. After generating a G-code, the file saved in this way should be transferred to a properly prepared device and the incremental manufacturing process should be started [40; 41; 42]. * Creation of a physical model: At this stage the design concept is implemented in the form of a physical object. This stage is accompanied by a set of activities aimed at precise determination of technological parameters, selection of devices from the machine park and their calibration, etc. * Control and verification is carried out in order to analyze whether the obtained component meets both the assumed quality parameters and expectations with regard to functionality. As presented in Figure 2, the relations between individual stages are in most cases bidirectional, i.e., the future solution should enable the return to previous stages in order to introduce corrections, improvements and modifications. Such an approach is consistent with the spiral model of the life cycle of a technical and technological project for industry 4.0 [43]. The developed model also implies 4 functional areas, which are not directly connected with only one stage of operation. This is due to the fact that in most cases they apply to all stages. The first group includes functionality related to defining, discussing and specifying initial project assumptions. These activities are often accompanied by a \"brainstorming\" and are connected with relations between many team members or teams. Within this group, the choice of the physical manufacturing method is also distinguished. At this point, it should be emphasized that currently there are many methods of physical production of objects in the process of rapid prototyping [44; 45; 46]. These methods must guarantee the results that are consistent with the initial assumptions. Furthermore, they require proper definition of technological parameters. The second functional group consists of basic elements of widely understood infrastructure including: ICT infrastructure, software, and full machine park. These elements are necessary for the proper functioning of the remote prototyping service based on a distributed system. This group includes both efficient servers, disk arrays, high-performance computer network, general and specialist software, manufacturing machines and equipment, as well as hardware control and supervision elements. The third functional group refers to providing coherence of operation of the whole system through integration of distributed resources, as well as access control and tariffication. This functionality must take into account different levels of access to different system resources located in different locations, companies, institutions and universities. Access to individual resources must be in accordance with the security policy and level of authorization adopted, or the purchased or split tariffication/license. The last functional area shall include all methods and means to ensure scalability, reliability, and security of system operation. They shall provide for the system to be used at local, regional, national or even international level. The model itself does not impose any specific solutions and mechanisms, as technological development in this area is very fast, and what is more, it is in line with the latest developments relating to the principle of openness of systems. When adapting the presented model (Figure 2), before developing the targeted system architecture, it is necessary to take into account the rapid prototyping process, the outline of which is presented in Figure 3.  
This diagram illustrates the process of rapid prototyping.