# A Survey of the Real-Time Metaverse: Challenges and Opportunities +
## 8 Challenges and Opportunities
### Interoperability and Standards
#### 8.3.5 Data Compatibility  
_Data compatibility_ ensures that different systems, platforms, and applications can effectively share, interpret, and use data across various environments [270]. These issues arise when there is no common format or protocol for data representation, storage, and exchange, leading to difficulties in integrating and synchronizing data across different virtual worlds and applications.  
In the metaverse, data compatibility is essential for a seamless user experience [18]. Users create and interact with various digital assets, including avatars, virtual goods, and user-generated content. When these assets are created in one environment but incompatible with others, users face significant barriers in transferring or utilizing their data across different platforms [10]. For instance, an avatar designed in one virtual world might not be recognized, or digital assets purchased in one marketplace might not be usable in another due to differences in data formats and structures.  
The lack of data compatibility hampers the metaverse's potential as a unified and interconnected digital universe [271]. To address these issues, there needs to be a concerted effort to develop and adopt common data standards and protocols. These standards would define how data should be formatted, stored, and exchanged, ensuring that it can be seamlessly interpreted and used across different systems. By achieving data compatibility, the metaverse can provide a more cohesive and integrated experience, allowing users to move fluidly between different environments and fully leverage their digital assets across the entire ecosystem. Common formats and data integration are the most important factors of data compatibility [267].  
Common formats in data compatibility within the metaverse are essential for ensuring seamless interoperability across various platforms, applications, and virtual environments [146; 223]. These standardized formats facilitate the consistent representation, storage, and exchange of data, allowing different systems to interpret and use the same data efficiently. Common formats are critical in avatars, digital identities, digital assets,virtual goods, user data, profiles, virtual currency, transactions, communication, interaction data, environments, and world data.  
Common formats like FBX (Filmbox), OBJ (wavefront object), and gITF (GL transmission format) are widely used for 3D models and animations for avatars and digital identities. These formats ensure that avatars created in one virtual world can be rendered and animated correctly in another [272]. Metadata formats such as JSON (JavaScript object notation) and XML (extensible markup language) are essential for including information about avatars, such as appearance, accessories, and customizations, ensuring consistent interpretation across platforms. Standardizing these formats helps maintain the visual and functional integrity of avatars and digital identities as they move across different virtual environments.  
For digital assets and virtual goods, standardized formats for textures and materials--such as PNGs (portable network graphics), JPEG (joint photographic experts group) for textures, and PBR (physically based rendering) materials--ensure that the visual quality of digital assets is maintained across various platforms [273]. Asset bundles packaged in standard formats like Unity Asset Bundles or Unreal Engine's asset format facilitate the transfer and usage of digital assets across different virtual worlds. Additionally, blockchain standards like ERC-20 or ERC-721 for tokens ensure that virtual currencies and digital collectibles can be managed and exchanged securely and interoperably [274].