   Scene graphs, hardware transforms, and matrix types
  Hello,I am implementing a scene graph, which will be traversed each frame to determine visibility of nodes, which get sent into a list sorted on texture/shader/etc. However I'm not sure what approach I should take with the matrix transforms. If the scene graph is traversed completely before any rendering takes place, how can I make use of the OpenGL matrix stack? Are these transformations commonly done in software or hardware?Also I'm having trouble deciding what kind of matrix to represent the transformations at transformation nodes. Should I just go for a 4x4 or a 4x3 to save some processing time?I've been reading through the scene graph resources but I haven't found the answer to these questions yet.Any suggestions?   
  Get a really solid matrix class together and do your own calculations. The visibility should be calculated using a minimum of points (if you are using AABB or other bounding objects), so the performance hit will be minimal. Then either load the matricies at each node using glLoadMatrix, or reperform the transformations with glRotatef, glTranslatef as you step through.   