How do I extract the output equations from a sfit object (linear interpolation) ?

Hi, I am trying to get equations from a sfit object.

I used cftool to create the sfit object. I have 3 dimensional data and I selected interpolation-> linear to get 3D surface.

I want to extract equations from the surface (sfit object). But, I couldn't find a way to do it.

If you could help me, I would be glad.

Regards