I read several tutorials how to place 3d objects in SceneKit/ARKit applications and all of them uses .scn format files for the objects. 

But I found there is no any issues if I use original .dae format and do not convert it to .scn format. 

I don't really see any difference between .dae and .scn formats.

Actually result seems to me the same but can you explain what the difference between them and what I should use in what cases?

Thank you!