For an options market making operation I need to be able to build a volatility surface, based on only 5 degrees of freedom, like e.g.: MaxPut, MaxCall, Skew, Curve and At The Money Vol.
Is there an existing model or mathematical function, that is able to replicate any given vol surface by using just these 5 degrees of freedom?
I am currently using the SABR model, but it cannot adjust to any vol curve. I have used Cubic Splines, but it is really difficult to calibrate it.