## 3 Metaverse Classroom: A Layered Architectural View  
### Infrastructure Layer  
#### 3.1.1 Platform Technology  
The platform technology of a Metaverse classroom serves as the essential foundation, enabling the creation and hosting of dynamic, interactive virtual environments [52]. It supports immersive 3D spaces and interactive features, making the virtual learning experience engaging and accessible [53]. Platforms like Unity, Unreal Engine, and AltspaceVR provide robust tools to build virtual worlds, offering graphical fidelity, customizability, and essential functionalities [54]. Unity and Unreal Engine are particularly well-suited for creating detailed educational simulations and virtual laboratories due to their powerful 3D rendering and scripting capabilities [55]. These platforms also support scripting and modular asset management, allowing developers to create customized spaces tailored to specific educational needs [56]. An effective platform must support virtual reality (VR) and augmented reality (AR) to enhance immersion. VR enables students to engage deeply with their environment through life-like simulations [57]. For example, science students could perform virtual dissections, and history students could explore ancient civilizations [58]. AR, on the other hand, overlays virtual elements onto the real world, enriching blended learning experiences [59]. Tools like ARKit and ARCore facilitate these integrations, allowing students to explore holographic models or engage with landmarks through mobile devices [60]. Combining VR and AR creates a flexible and versatile learning environment [60]. Scalability is a critical feature of Metaverse platforms, as it ensures that the classroom can accommodate a wide range of devices and user volumes [16]. These platforms must be accessible on various devices such as VR headsets, PCs, tablets, and smartphones to ensure inclusivity [61]. They should also manage varying numbers of users efficiently to maintain performance, whether for small lab activities or large lectures [62]. Platforms like AltspaceVR offer infrastructure for large groups, while Unity and Unreal allow performance customization across different devices [63]. Scalability ensures the classroom can grow with minimal disruption as user needs evolve [53]. Platform technology must also support integrations with additional tools and plugins to enhance functionality [64]. These integrations can include AI tools for personalized learning paths, analytics to track student engagement, and gamification features like quizzes and rewards [65]. Unity and Unreal can connect with third-party tools, such as IBM Watson for AI-driven customization or Kahoot for interactive assessments, through plugins and APIs [66]. This extensibility enables the creation of adaptive, interactive classrooms that meet diverse educational requirements [67]. Finally, data security and encryption are integral to platform technology to protect sensitive student information [68]. Platforms must comply with data protection standards like the General Data Protection Regulation (GDPR) and the Family Educational Rights and Privacy Act (FERPA) to ensure privacy [69]. Unity and Unreal offer documentation on data encryption, and platforms like AltspaceVR have built-in security features [54]. Strong security protocols prevent unauthorized access, allowing students to participate in virtual learning safely [70]. By prioritizing security, platform technology creates a safe and stable learning experience [56]. Figure 1 illustrates the conceptual layers of the Metaverse classroom, providing a foundation for understanding its structure and applications. Also, Table 1 represents the MoSCoW (must-have, should-have, could-have) prioritization for essential features critical to the foundational functionality of the Metaverse classroom.