gradient of a surface property along the surface

Hi,

I wonder if I can calculate the gradient of a surface property (curvature, surface energy, surface charge, etc.) along the surface?
(d(curvature)/ds) both 2D and 3D...

Note:
I know that d(phi)/ds = tx*d(phi)/dx+ty*d(phi)/dy+tz*d(phi)/dz
but I doesn't work.
d(curv1,x) gives zero so it doesn't work for curvature and also for other properties...
I tried quality options like smoothing and recovery also...

Thanks...

Aytac Celik