I am beginning on a project consisting of a high performance game server that serves multiple clients. The target game is a real-time 3D model renderer, the wishful thinking is to achieve something like Povray, or even adopt the libraries. I am not sure whether I should also use an open-source game engine such as Quake (II or III) ? Or I should go for OpenGL or DirectX. So, there's 2 part here, the 3D real-time model rendering game and a game server that utimately dishes out other client/server games. Please advise the right architecture, pros & cons, and right combination of open-source engine & libraries, so as to start right.