*.object files are compatible between all (soc, cs, cop) SDK, regardless they are map geometry, static objects, npc/monster modells etc.
*.ogf files are very different case, these are object files with animations converted into ogf files: SOC character modells, and CS/COP character modells are different, CS/COP npc modells have 2 extra bones. Some COP monsters are different too from SOC/CS monsters, because they have very different bone structures.
"Some sort of pressure must exist; the artist exists because the world is not perfect. Art would be useless if the world were perfect, as man wouldn’t look for harmony but would simply live in it. Art is born out of an ill-designed world."