Data fitting with 3 independent variables

Hi everybody,

I have a dataset of four variables: 3 independent and one dependent. Is there any way to fit the dependent variable expressing it as a function of the other ones, i.e. z = f(x1, x2, x3)? Please note that I don't know the "shape" of the function.

For curve and surface fitting I use TableCurve 2D and 3D, but can't find any software to do just what I need now.

Any input on this would be extremely appreciated.

Best regards.