   My 3D Engine can't play animation
  I know nothing about directX. Is there a way to know what version of directX a .x is made. I have a model that come with the engine that have a animation that work. I created one and it play in DirectX viewer (I have the sdk), but it won't play in the game engine.Is there a software I can send my animation and save it back into another version?   
  What engine are you using?Your X file might use a method of animation that is unsupported by the engine.   ;  yeah directx .x files is pretty standard across the big boysblender can load it. but your problem isn't the file its the code since you know little about it. msdn have some tutorials on getting animation done. basically you must tell it to play the animation and when it should update to the next frame   