RealXtend vs. Second Life RealXtend overview  Main ambition Promote the evolution of 3D web Promote virtual world standards  Open source  Based on OpenSimulator  Consists of viewer, Naali, and server suite, Taiga

RealXtend vs. Second Life Second Life overview  Largest install base, most popular virtual world platform  Proprietary  Viewer only is open source

Second Life Architecture Monolithic Very entangled Two domains: Agent and Regionhttp://wiki.secondlife.com/wiki/Structural_Desi gn_Overview  Architectures of both are identical  Consists of hosts, services, and stores

RealXtend Architecture Seeks to be “robust, extensible, and flexible” Three main elements: Entity-Component (EC) scene model, core API, network protocol  EC scene model: Any component that contains arbitrary data can be added to a generic entity  Core API: implements basic functionality (e.g. display graphics, manipulate scene, user input)  Network protocol: Extensible and allows applications to define custom messages Three main technologies: Qt, Ogre3D, and kNet, which implement core API and EC

RealXtend Architecture: Modularity Consists of a number of modules, core and user- defined Modules implement a functionality or service Modules have a minimal dependency on one another Events are passed along hierarchy of modules

RealXtend Architecture: Extensibility Modules/features implemented as plug-ins can be enabled/disabled at runtime and are not distinct to a particular entity Can easily add new module or override old module to add/change a functionality without having to change the system

RealXtend Architecture: Entity- Component All objects on scene are represented as entities Each entity has a number of components (e.g. light, mesh, scripts, etc.) attached to it Concept of actions  Write Javascript/Python code for entity to manipulate components

Scripting Second Life  Uses Linden Scripting Language  Effects available immediately RealXtend  Uses Python  Must reload Both  Need scripting privileges

Graphics Second Life  Uses prims  Just now starting to support mesh RealXtend  Uses OGRE 3D graphics rendering engine  Supports meshes for avatar, terrain, objects  Can display shadows and particle effects  Can import scenes from Blender

Community Second Life  ~10m total residents  RealXtend  ~30,000

Use Cases Similar for both  Conferencing  Games  Simulation  Socialization

Scalability Second Life  50 avatars per region RealXtend  Unlimited number of entities

Conclusions Depending on what definition you take of a virtual world  Similar in a broad sense Both offer basic virtual world functionalities  Different in terms of implementation Modular vs. monolithic Feasibility/practicability of using realXtend instead of Second Life?