Hello everyone I want to create a lead for a 3D structure, but when I run the program, I get the following error: ###No sites close to (0, 0, 14) are inside the desired shape.### Please help me find the mistake. Thanks in advance for your reply. #### import kwant from matplotlib import pyplot lat = kwant.lattice.general([(0, 0.5, 0.5), (0.5, 0, 0.5), (0.5, 0.5, 0)], [(0, 0, 0), (0.25, 0.25, 0.25)], name=['a1', 'a2']) a1, a2 = lat.sublattices def make_cuboid(a=10, b=10, c=15): def cuboid_shape(pos): x, y, z = pos return 0 <= x < a and 0 <= y < b and 0 <= z < c syst = kwant.Builder() syst[a1.shape(cuboid_shape, (0, 0, 0))] = 1 ## the same on-site foar a1 and b1 syst[a2.shape(cuboid_shape, (0, 0, 0))] = 1 syst[lat.neighbors()] = 1 def lead_shape(pos): x,y,z = pos return 0 <= x < a and 0 <= y < b and 14 <= z < c lead = kwant.Builder(kwant.TranslationalSymmetry([1,0,0])) lead[lat.shape(lead_shape, (0, 0, 14))] = 1 lead[lat.neighbors()] = 1 return syst,lead def main(): syst,lead = make_cuboid() kwant.plot(syst) syst = syst.finalized() syst = make_cuboid(a=1.1, b=1.1, c=1.1) def family_colors(site): return 'r' if site.family == a1 else 'g' syst.attach_lead(lead) kwant.plot(syst, site_size=0.18, site_lw=0.01, hop_lw=0.05, site_color=family_colors) if __name__ == '__main__': main() #####