I try to save it as eps file, but matlab default setting save it as bitmap instead of vector format (it doesn't happen for 2D plot). I then go to Export Setup > Rendering > tick Custom renderer with painter (vector format), but it gives me the contour plot under 3D surface plot. I have tried to use surf() instead, but it gives me a blank graph. I think MatLab saves the XY plane without projection of Z values, instead of the figure in 2D view. Does anyone have an alternative solution? Thanks!