Alex,
Unfortunately the polyfit VI does not have support for cylinderal coordinate system. Could you implement a system in which for every XY plane in your dataset (for a unique z) you complete a polynomial fit, whether it be horizontal or vertical on your human torso? In general the polynomial fit is for a 2-D curve and not for polynomial fitting of a 3-D mesh.
Cheers,
Jonah
Applications Engineer
National Instruments
Jonah Paul
Marketing Manager, NI Software