Faced with the advantages of cross-platform compatibility, distributed processing, and high reliability of networked programs, the development direction of general-purpose software is from stand-alone versions to C/S and then to B/S. The challenge of networking simulation software is how to quickly transition to a B/S network architecture while making the most of existing resources. This paper proposes an improved model that combines Java and VRML to directly upgrade a stand-alone simulation system to a B/S architecture. Furthermore, the feasibility of the proposed method is verified using a spiral bevel gear CNC simulation system as an example. 1 Introduction With the development of virtual reality technology, simulation technology in the manufacturing industry has developed rapidly, especially in virtual machine tool simulation systems. Due to its positive impact on shortening production and development cycles, reducing R&D costs, and improving production efficiency, virtual simulation has received widespread attention and research. The simulation machining system implemented by Liu Xiaohui et al. was developed using a combination of VC++ and OpenGL, a common development method adopted by most domestic industrial simulation software providers. Similar methods include VB plus OpenGL and VB plus D3D. Based on AutoCAD as the graphics library, VC++ as the main development environment, and MATLAB as the numerical calculation support module, the author and Xiong Yuedong developed a spiral bevel gear CNC simulation system. Huo Zhipu summarized four methods of traditional simulation system software, basically covering the current development models of industrial simulation systems. Furthermore, he implemented a networked remote simulation system platform using a network-based Java environment combined with VRML. With the advent of the network age, the networking of programs is booming. The intellectual property rights of standalone software are very difficult to guarantee. Bundling hardware dongles only adds extremely limited protection. Moreover, upgrading and updating standalone programs is very inconvenient. Their security is also very poor, making them easy to crack and tamper with. At the same time, for different operating systems, standalone software usually requires the development of different versions, resulting in poor portability. Therefore, more and more software is moving away from standalone and towards networking. In this environment, the so-called C/S (Client/Server) model has emerged. It is a transformation of standalone software towards networking. It usually appears as a combination of standalone software sales and online real-time upgrade and update services. However, since the main software resources still reside on the client machine, its security cannot be guaranteed. The emergence of the B/S (Browser/Server) model perfectly solves these problems. Because it uses widely adopted web browsers as clients, the user interface is user-friendly and consistent; the logic layer is transferred to the server side, saving development time; and the greatest advantage of B/S lies in its powerful cross-platform portability. However, simulation system software faces an awkward situation. If it is networked using the C/S model, the workload is not large, but due to the real-time animation generation required by the simulation system, network transmission limitations mean that most of the software code must still be placed on the client machine, thus the security problem remains unsolved; it is merely equivalent to adding an online upgrade and update function. If it is modified to the B/S model, placing most of the software resources directly on the server side, the data transmission problem becomes even more insurmountable. Huo Zhipu et al. directly used a Java environment in the B/S model combined with VRML to establish a robot simulation system, creating a networked embedded remote simulation system. Li Ran et al. discussed in detail how to combine VRML and Java to create interactive dynamic scenes. Leveraging VRML's advantages in 3D modeling and Java's strong interactive features and cross-platform capabilities, it becomes remarkably convenient to implement complex, highly interactive dynamic scenes on the internet. Furthermore, VRML is introduced in detail, including its node-based organization and its specific integration with Java. Undoubtedly, this B/S-based networked cross-platform development model has many advantages over traditional development. However, completely discarding past code and starting from scratch when moving towards networking is unacceptable. Many software vendors have chosen to first transition to C/S. However, as we have discussed, this transition is far from thorough. [IMG=Figure 1 Development and Brief Structure of Spiral Bevel Gear Simulation System]/uploadpic/THESIS/2007/11/2007111411053795960Y.jpg[/IMG] Figure 1 Development and Brief Structure of Spiral Bevel Gear Simulation System [IMG=Figure 2 Main Interface of Spiral Bevel Gear Simulation System]/uploadpic/THESIS/2007/11/20071114111116726654.jpg[/IMG] Figure 2 Main Interface of Spiral Bevel Gear Simulation System [IMG=Figure 3 Graphical Interface of Network Version Simulation System]/uploadpic/THESIS/2007/11/2007111411154046134A.jpg[/IMG] Figure 3 The purpose of this paper is to find a reasonable method to directly transform the simulation system into a new generation of remote virtual machining system with a B/S architecture, while making full use of existing software resources, and to summarize this method into a general one. 2 Introduction to the Standalone Version of the Spiral Bevel Gear CNC Simulation System The standalone version of the spiral bevel gear CNC simulation system, developed at the end of 2004, was a research project to adapt to the advancement of spiral bevel gear machine tools from traditional rocker table type to 5-axis linkage CNC type. The system implementation scheme is a program developed by combining VC++ with AutoCAD's ObjectARX library and MATLAB as the numerical calculation development environment. Its simplified structure is shown in Figure 1. The main interface of the standalone version of the software is shown in Figure 2. 3 VRML Language and JAVA Development Platform 3.1 Introduction to VRML Language VRML (Virtual Reality Modeling Language) is a new technology developed by the close integration of Internet technology and virtual reality technology. It aims to create realistic interactive 3D scenes on the Internet and become an effective 3D file exchange format. VRML technology integrates 3D, 2D, text, and multimedia. When combined, this creates entirely new interactive applications. VRML was officially approved as an international standard in 1998 (ISO/IEC 14772-1:1997, VRML97). Because VRML fills the gap in HTML's ability to display only 2D information and overcomes the limitations of the original WWW's monotony and poor interactivity, it has become the main standard for the Internet's 3D virtual world. Currently, most 3D graphics software, such as 3DS MAX, has developed VRML file format output interfaces. 3.2 Introduction to the Java Language The Java language has only been around for four years, but its development has been extremely rapid. Java breaks away from the hybrid language structure of C++ and is a true object-oriented language. Java quickly attracted widespread attention after its emergence. Java's most important and superior feature is its platform independence. Through a structure-neutral virtual machine, its programs can run on any computer across operating system platforms. This is a feature that no previous language possessed. In addition, its ease of use, distributed processing, and excellent security have made it increasingly popular. Java has a wide range of applications, among which the creation of dynamic interactive web pages using JavaScript combined with Java web applications is an important application direction for Java. Because VRML fills the gap in HTML's ability to display planar information and overcomes the original weaknesses of the WWW (monotonous and poorly interactive), it has become the main standard for the Internet's three-dimensional virtual world. Currently, most 3D graphics software, such as 3DS MAX, has developed VRML file format output interfaces. In short, the combination of Java and VRML provides a practical and effective development environment for realizing distributed B/S mode virtual simulation systems. 4. Networking of Standalone Simulation Systems To achieve networking of a standalone system, the three main modules in Figure 1 must be networked and distributed in an acceptable form. The numerical calculation module developed by MATLAB is loaded as a DLL dynamic link library. Therefore, in the network version, it can also be placed on the server side and accessed by the Java main module. The graphics motion module developed using Object ARX in the VC environment needs to first convert the standalone version's graphics display scene into VRML language format. The converted graphical interface is shown in Figure 3. Then, the module can be modified according to the corresponding motion defined in the original program. For simple motion, sensor nodes and movement position nodes can be converted. For complex interactive motion, Script nodes enable VRML to interact with Java or JavaScript, simulating the machining process through event handling. Finally, the main module modification involves transforming the form-based Windows program into a dynamic web application. Since VC and Java are object-oriented, they can be modified to a Java-recognizable format based on their corresponding structures. This completes the networking of the spiral bevel gear simulation system. 5. Conclusion This paper analyzes and compares traditional simulation software development models and network-based development models, describes the application of VRML and Java, and after analyzing the advantages and disadvantages of stand-alone simulation software and B/S-based networked simulation software, proposes a feasible solution for upgrading from stand-alone simulation software to B/S-based networked simulation software. The correctness of the solution is verified using a spiral bevel gear virtual simulation system as an example. Due to the widespread use of VRML, most graphics software has a VRML interface, making the modification model presented in this paper more universally applicable. Proceedings of the 2nd Servo and Motion Control Forum and the 3rd Servo and Motion Control Forum