ios – iPhone: what combination of gestures should I use to manipulate a 3D model?

I hope I’m asking in the right place. Anyway: I am working on an AR map where I load a model onto the screen, and I’d like to allow the user to do the following:

  1. Scale size
  2. Move up/own/sideways, so basically X/Y axes.
  3. Move forward/backward, z axis

So for scaling I think of pinching, for moving on the X/Y axes one finger pan/drag.

What would be a good gesture to use for the 3rd use case?