Hello there, I posted this on the graphic board and nobody seemed to care. Since I implement my engine under OpenGl, I decided to repost it here. Im SirCyr, long time reader first time poster... I''m designing a 3D engine to be used in a space shooter game using OpenGl. I was thinking about how I will render my object list and I came up with the following thoughts or question: -> Each object polygons would be only stored once in the graphic engine and located at the origin. So if I want to have two spaceships that use the same mesh, I would use two object "handles" that would bind a different texture and position to the polygon mesh. -> My meshes would be stored in a database that would be sorted in a shader tree(As suggested on the Delphi3D site lately) to eliminate state changes as much as I can. Should I build that tree only once? or at each frame for the polygon that are visible...And, if the same mesh, at a given node, is used by more than one model. Does it means that I can''t render them only by one call to OpenGl since I have to transform that mesh two times...Ideally I would like to make only one render call for all the meshes that shares the same texture settings...Do you have some ideas how to acheive that? thansk!