How is defined the support plane ?



The Structure SDK provides the STCameraPoseInitializer which is able to provide a support plane.
After some tests, I’m not able to understand what it looks like.

I’m currently working with the pose initializer top cube (1m x 1m x 1m), my device (iPad 6th) is oriented 60° from the ground (almost vertical), in landscape (round button to the right) and the provided support plane is the following: ( 0.00 ; -0.62 ; -0.78 ; 0.77 )

My questions are the following:

  • What is the “support plane” in terms of geometry, in terms of the real world physics ?
  • In which coordinate system is this plane expressed ?

Thanks in advance