How to create a good engine with my existing class

I want to create an engine with my existing class, but i don’t know how to arrange it.
Do u have any idea abt it?

  1. Camera
  2. frustum culling
  3. quadtree
  4. sound
  5. 3ds Model class
  6. Network
  7. Skybox
  8. AI
  9. tree (create 2 quad with blending
    texture) movement
    12.heightmap class
    14.collision detection

What objects need to add in?

[This message has been edited by cwc36 (edited 02-16-2003).]

Better look at how good engines are organized - Crystal Space is an excellent but complex example.