Home Forums Nazca bbox bug Reply To: bbox bug


Hey Joe,

There are some pro’s and con’s of a hull vs. bbox. A convex hull is like a rubber band around the shapes. It can not be assigned a top-right etc corner like a rectangular bbox. The bbox is not supposed to be the tightest shape under rotation, it serves another purpose, like placement convenience, vizualization or finding overlaps with other boxes efficiently. Hulls take an order longer to calculate, so default they are off. Note that for your topcell of interest you do want a width and a height, according to a rectangular bbox, if I understand correctly, which depends on the orientation of that topcell.

A way to get the tight bbox of your top cell is to flatten it and get the bbox for that flattened cell. This can be done with the cell_iter(). I also switched the hull on for the flattened cell. The hull has a lot more points than a bbox in this case, due to the outside of the bend being part of the hull.

import nazca as nd
from nazca.interconnects import Interconnect as IC

#  Interconnect settings
XS = 'xs1'
nd.add_layer2xsection(xsection=XS, layer=1)
IC_1 = IC(width=1, radius=80, xs=XS)

# main
with nd.Cell('main') as main:
    IC_1.bend(angle=45).put(0, 0, 45)

nd.cfg.use_hull = True # switch on hull calculations.
lyo = nd.layout()
for P in nd.cell_iter(main, flat=True):
    if P.cell_start:
        if P.level == 0:
    if P.cell_close and P.level == 0:

# output
(-0.35355339059327373, -0.3535533905932738, 23.931457505076203, 56.56854249492379)
[[-3.53553391e-01  3.53553391e-01]
 [ 3.53553391e-01 -3.53553391e-01]
 [ 7.07106781e-01 -3.88578059e-16]
 [ 1.19628836e+00  5.01371256e-01]
 [ 1.75083025e+00  1.07841601e+00]
 [ 2.29960800e+00  1.66094527e+00]
 [ 2.84256736e+00  2.24890147e+00]
 [ 3.37965467e+00  2.84222649e+00]
 [ 3.91081685e+00  3.44086168e+00]
 [ 4.43600139e+00  4.04474789e+00]
 [ 4.95515640e+00  4.65382541e+00]
 [ 5.46823055e+00  5.26803407e+00]
 [ 5.97517314e+00  5.88731314e+00]
 [ 6.47593406e+00  6.51160141e+00]
 [ 6.97046382e+00  7.14083720e+00]
 [ 7.45871354e+00  7.77495830e+00]
 [ 7.94063497e+00  8.41390203e+00]
 [ 8.41618046e+00  9.05760525e+00]
 [ 8.88530302e+00  9.70600434e+00]
 [ 9.34795629e+00  1.03590352e+01]
 [ 9.80409452e+00  1.10166333e+01]
 [ 1.02536727e+01  1.16787337e+01]
 [ 1.06966462e+01  1.23452708e+01]
 [ 1.11329715e+01  1.30161789e+01]
 [ 1.15626053e+01  1.36913915e+01]
 [ 1.19855052e+01  1.43708421e+01]
 [ 1.24016294e+01  1.50544633e+01]
 [ 1.28109367e+01  1.57421877e+01]
 [ 1.32133867e+01  1.64339473e+01]
 [ 1.36089397e+01  1.71296737e+01]
 [ 1.39975565e+01  1.78292981e+01]
 [ 1.43791987e+01  1.85327515e+01]
 [ 1.47538286e+01  1.92399642e+01]
 [ 1.51214092e+01  1.99508663e+01]
 [ 1.54819041e+01  2.06653877e+01]
 [ 1.58352777e+01  2.13834576e+01]
 [ 1.61814951e+01  2.21050052e+01]
 [ 1.65205221e+01  2.28299590e+01]
 [ 1.68523251e+01  2.35582475e+01]
 [ 1.71768714e+01  2.42897986e+01]
 [ 1.74941289e+01  2.50245401e+01]
 [ 1.78040662e+01  2.57623993e+01]
 [ 1.81066526e+01  2.65033033e+01]
 [ 1.84018584e+01  2.72471789e+01]
 [ 1.86896543e+01  2.79939526e+01]
 [ 1.89700119e+01  2.87435505e+01]
 [ 1.92429034e+01  2.94958985e+01]
 [ 1.95083019e+01  3.02509224e+01]
 [ 1.97661811e+01  3.10085474e+01]
 [ 2.00165156e+01  3.17686987e+01]
 [ 2.02592806e+01  3.25313011e+01]
 [ 2.04944522e+01  3.32962794e+01]
 [ 2.07220070e+01  3.40635578e+01]
 [ 2.09419226e+01  3.48330605e+01]
 [ 2.11541773e+01  3.56047115e+01]
 [ 2.13587500e+01  3.63784346e+01]
 [ 2.15556206e+01  3.71541532e+01]
 [ 2.17447696e+01  3.79317906e+01]
 [ 2.19261783e+01  3.87112701e+01]
 [ 2.20998288e+01  3.94925145e+01]
 [ 2.22657039e+01  4.02754467e+01]
 [ 2.24237872e+01  4.10599893e+01]
 [ 2.25740631e+01  4.18460647e+01]
 [ 2.27165167e+01  4.26335952e+01]
 [ 2.28511340e+01  4.34225030e+01]
 [ 2.29779017e+01  4.42127101e+01]
 [ 2.30968072e+01  4.50041385e+01]
 [ 2.32078387e+01  4.57967098e+01]
 [ 2.33109853e+01  4.65903459e+01]
 [ 2.34062369e+01  4.73849681e+01]
 [ 2.34935839e+01  4.81804980e+01]
 [ 2.35730178e+01  4.89768570e+01]
 [ 2.36445307e+01  4.97739663e+01]
 [ 2.37081155e+01  5.05717472e+01]
 [ 2.37637660e+01  5.13701208e+01]
 [ 2.38114766e+01  5.21690081e+01]
 [ 2.38512427e+01  5.29683304e+01]
 [ 2.38830602e+01  5.37680084e+01]
 [ 2.39069262e+01  5.45679633e+01]
 [ 2.39228381e+01  5.53681159e+01]
 [ 2.39314575e+01  5.60685425e+01]
 [ 2.39314575e+01  5.65685425e+01]
 [ 2.29314575e+01  5.65685425e+01]]