Crystal Space is an Open Source 3D SDK for Unix, Windows, and MacOS/X. It renders with OpenGL and features GLSL shaders, CG shaders, deferred rendering, dynamic shadows, bullet based physics library, terrain engine, skeleton based animation meshes, exporter for Blender, portals, etc...
Server and Client XML exchange via reflection. AJAX,PHP,JAVA and PERL reflection helper classes. Full NIO server for JAVA and RMI service. Basically create a PlugIN and let reflection do the work for you.