Need to make an equation driven surface...

All:

I need to define a part with that has a solid surface which is a 4th order polynomial of form z = f(r, theta); cylindrical coordinates.

can soldworks do this? I can see how to do equation driven curves, but not surfaces. Do i need to convert to cartesian z = f(x,y) first?

help!

Thanks in advance all

Jason

SolidworksSurfacing