How to change zdata of Poly3DCollection object?

Question

I am currently modifying the xdata and ydata properties for the Line2D object as follows:

plt.setp(ph, xdata=event.xdata,ydata=event.ydata); thisline.figure.canvas.draw(); 

I would like to do the same for a surface plot like Poly3DCollection, however Poly3DCollection does not have zdata property, therefore

 plt.setp(surf,zdata=z_surface); 

does not work. At the moment, I am re-creating the plot using plot_surface, but it is very slow and creates other problems. Is it better to talk about this? I want to change the zdata graph in real time.