Question: How to compute the surface area of a numerically defined isosurface?

Hi all,

I am trying to define iso surfaces mathematically. From teh output of a numerical simulation, I have a 3d field of a parameter called MF. So, MF = MF (x,y,z).

So, when I have MF = constant, I will hypothetically have the equation for a surface called x = f(y,z). As I said it's the output of a simulation so I don't have a defined function for MF. Now, I wanted to calculate the surface area on a constant value of MF. I know that the way to calculate a surface is: integral of(1=Fx^2 +Fy^2)^0.5. on the other hand I know that MF = 11, everywhere on the surface. I am trying to come up with an expression for surface area, based on special derivatives of MF. I started by assuming a potential field for MF, but I didn't get to a conclusion and got a little confused. I would greatly appreciate any comments or helps.

Thanks,

Haley