'Label center' of 3D surface patch instead of centroid

Dear All,

I have an irregular 3d surface patch expressed as vertices (x,y,z) coordinates and faces (triagles), this can be concave or convex or more complex. Since the centroid as usually calculated can lie outside the surface, I need the 'label' center, the farthest away point from the countour inside the surface, on the surface. Thank you, Octavian