#!/usr/bin/env python  header = 'Stellated rhombic dodecahedron made of pyramids and half-cubes by CMG Lee.'  import re, struct, math def fmt(string): ## string.format(**vars()) using tags {expression!format} by CMG Lee  def f(tag): i_sep = tag.rfind('!'); return (re.sub('\.0+$', '', str(eval(tag[1:-1])))   if (i_sep < 0) else ('{:%s}' % tag[i_sep + 1:-1]).format(eval(tag[1:i_sep])))  return (re.sub(r'(?<!{){[^{}]+}', lambda m:f(m.group()), string)          .replace('{{', '{').replace('}}', '}')) def append(obj, string): return obj.append(fmt(string)) def tabbify(cellss, separator='|'):  cellpadss = [list(rows) + [''] * (len(max(cellss, key=len)) - len(rows)) for rows in cellss]  fmts = ['%%%ds' % (max([len(str(cell)) for cell in cols])) for cols in zip(*cellpadss)]  return '\n'.join([separator.join(fmts) % tuple(rows) for rows in cellpadss]) def hex_rgb(colour): ## convert [#]RGB to #RRGGBB and [#]RRGGBB to #RRGGBB  return '#%s' % (colour if len(colour) > 4 else ''.join([c * 2 for c in colour])).lstrip('#') def viscam_colour(colour):  colour_hex      = hex_rgb(colour)  colour_top5bits = [int(colour_hex[i:i+2], 16) >> 3 for i in range(1,7,2)]  return (1 << 15) + (colour_top5bits[0] << 10) + (colour_top5bits[1] << 5) + colour_top5bits[2] def roundm(x, multiple=1):  if   (isinstance(x, tuple)): return tuple(roundm(list(x), multiple))  elif (isinstance(x, list )): return [roundm(x_i, multiple) for x_i in x]  else: return int(math.floor(float(x) / multiple + 0.5)) * multiple def flatten(lss): return [l for ls in lss for l in ls] def rotate(facetss, degs): ## around x then y then z axes  (deg_x,deg_y,deg_z) = degs  (sin_x,cos_x) = (math.sin(math.radians(deg_x)), math.cos(math.radians(deg_x)))  (sin_y,cos_y) = (math.sin(math.radians(deg_y)), math.cos(math.radians(deg_y)))  (sin_z,cos_z) = (math.sin(math.radians(deg_z)), math.cos(math.radians(deg_z)))  facet_rotatess = []  for facets in facetss:   facet_rotates = []   for i_point in range(4):    (x, y, z) = [facets[3 * i_point + i_xyz] for i_xyz in range(3)]    if (x is None or y is None or z is None):     facet_rotates += [x, y, z]    else:     (y, z) = (y * cos_x - z * sin_x,  y * sin_x + z * cos_x) ## rotate about x     (x, z) = (x * cos_y + z * sin_y, -x * sin_y + z * cos_y) ## rotate about y     (x, y) = (x * cos_z - y * sin_z,  x * sin_z + y * cos_z) ## rotate about z     facet_rotates += [round(value, 9) for value in [x, y, z]]   facet_rotatess.append(facet_rotates)  return facet_rotatess def translate(facetss, ds): ## ds = (dx,dy,dz)  return [facets[:3] + [facets[3 * i_point + i_xyz] + ds[i_xyz]                        for i_point in range(1,4) for i_xyz in range(3)]          for facets in facetss]  ## Add facets facet_sidess        = [[None,0,0,   0, 0,0, 20,20,-20, -20, 20,-20]] facet_basess        = [[None,0,0, -20,20,0, 20,20,  0,  20,-20,  0]] facet_basess       += rotate(facet_basess, (0,0,180)) facet_1_pyramidss   = translate(facet_sidess, (0,0,-1)) facet_1_pyramidss  += rotate(facet_1_pyramidss, (0,0,-90)) facet_1_pyramidss  += rotate(facet_1_pyramidss, (0,0,180)) facet_1_pyramidss  += translate(facet_basess, (0,0,-21)) facet_3_pyramidss   = facet_1_pyramidss.copy() facet_3_pyramidss  += rotate(facet_1_pyramidss, (-90,0,0)) facet_3_pyramidss  += rotate(facet_1_pyramidss, (0,90,0))  facet_sixth_cubess  = facet_sidess.copy() facet_sixth_cubess += rotate(facet_sixth_cubess, (0,0,-90)) facet_sixth_cubess += translate(facet_basess, (0,0,-20)) facet_half_cubess   = facet_sixth_cubess.copy() facet_half_cubess  += rotate(facet_sixth_cubess, (-90,-90, 0)) facet_half_cubess  += rotate(facet_sixth_cubess, ( 90,  0,90)) facetss             = (rotate(translate(facet_3_pyramidss, (22,22,22)), (0,0,180)) +                               translate(facet_half_cubess, (22,22,22))              ) facetss            += rotate(facetss, (-90,0,0)) facetss            += rotate(facetss, (180,0,0)) # facetss = [facets[:3] + facets[6:9] + facets[3:6] + facets[9:] for facets in facetss] ## flip  ## Calculate normals for facets in facetss:  if (facets[0] is None or facets[1] is None or facets[2] is None):   us      = [facets[i_xyz + 9] - facets[i_xyz + 6] for i_xyz in range(3)]   vs      = [facets[i_xyz + 6] - facets[i_xyz + 3] for i_xyz in range(3)]   normals = [us[1]*vs[2] - us[2]*vs[1], us[2]*vs[0] - us[0]*vs[2], us[0]*vs[1] - us[1]*vs[0]]   normal_length = sum([component * component for component in normals]) ** 0.5   facets[:3] = [-round(component / normal_length, 10) for component in normals]  print(tabbify([['N%s'  % (xyz   )                   for xyz in list('xyz')] +                ['%s%d' % (xyz, n) for n in range(3) for xyz in list('XYZ')] + ['RGB']] + facetss)) ## Compile STL outss = ([[('STL\n\n%-73s\n\n' % (header[:73])).encode('utf-8'), struct.pack('<L',len(facetss))]] +          [[struct.pack('<f',float(value)) for value in facets[:12]] +           [struct.pack('<H',0 if (len(facets) <= 12) else                             viscam_colour(facets[12]))] for facets in facetss]) out   = b''.join([bytes(out) for outs in outss for out in outs]) # out += ('\n\n## Python script to generate STL\n\n%s\n' % (open(__file__).read())).encode('utf-8') print("# bytes:%d\t# facets:%d\ttitle:\"%-73s\"" % (len(out), len(facetss), header[:73])) with open(__file__[:__file__.rfind('.')] + '.stl', 'wb') as f_out: f_out.write(out)