   scene graph?
  I saw something about scene graph.. I get the idea that it is some sort of Object/mesh sorting stuff with nodes and leafs and so.. but I can''t understand how it works.. how to store the objects and the materials(textures) and so on.. I guess I store my object one time at some place and then I use a pointer (or more pointers) to that object. but I don''t understand how to store everything.. ok, an object structure isn''t to hard to create.. but then how do I do the nodes and leafs and so?and then how to render the mesh with the material they want without change material more then I need draw all objects using the same material then change to the next material..can someone give me a simple answer or some sort of pseudo code or some easy example code ? 
Whether a scene graph should store materials and states depends on personal preference. Some people manage their whole engine off a single scene graph; others use them purely for objects, with things like materials being properties of the object rather than nodes in the graph.Some links:http://openscenegraph.sourceforge.net/http://www.sgi.com/software/performer/   --Simon O''Connorex  -Creative AsylumProgrammer &Microsoft MVP