Convert 3d models from fbx to scenekit

I bought a 3d dog animated models from sketchfab. It included fbx,3dmax,gITF formats. I need to convert one of these file to ios scenekit (dae or scn) [login to view URL] We are importing dae file into xcode and covert dae to .scn for ios scenekit. so we will need : The materials and animations work on xcode in dae format models should have one root node instead of scattered objects scale measured in meter(some times the model is huge after importing as original model may be in cm)