How to use "mphinterp" to extract information from a 2-D axisymmetric simulation case

Hello all,

I have a question on mphinterp function in MATLAB livelink for COMSOL. I want to extract the electric field intensity (ewfd.normE) in a specified domain (surface) of a 2-D axisymmetric simulation case. Thus the coordinates are "r, z" (cylindrical coordinates) instead of the global "x,y,z" (cartesian coordinates). How to use mphinterp function for the cylindrical coordinates instead of the cartesian coodinates?

Thanks,
Jinlong