Changing the line color in plot_surface

I did a surface plot with some data in Python. Now I tried to change the style of such a plot. But unfortunately I am stuck in the line color. It's default is black, but I want to make it red or any other color. My code is: ``` from mpl_toolkits.mplot3d import Axes3D import matplotlib.pyplot as plt from matplotlib import cm import numpy as np data=np.loadtxt("test.txt") def formateU(data): U = np.zeros((20,20)) for value in data: U[value[0],value[1]] = value[2] return U U = formateU(data) y,x=np.meshgrid(np.linspace(0.,19,20),np.linspace(0.,19,20)) fig = plt.figure() ax=plt.axes(projection='3d') ax.plot_surface(x,y,U,rstride=1,cstride=1,alpha=0,linewidth=0.5) ax.view_init(30, 45) plt.savefig("test.png") plt.show() ``` It' seems obvious that it has to be an additional argument in: ``` ax.plot_surface(x,y,U,rstride=1,cstride=1,alpha=0,linewidth=0.5) ``` but I can't figure it out. Can you help me please? The test.txt is available at http://www.file-upload.net/download-8564062/test.txt.html