N = 30 # number of grid intervals on the unit sphere
rmax = 1.5 # line length
x0 = [0, 0, 0] # set object at this position
#############################################################
shape = load(datadir + 'pumpkin.vtk').normalize().pos(x0).lineWidth(.1)
show(shape, at=0, N=2, bg='w', axes={'zxGrid': False})
############################################################
# cast rays from the center and find intersections
agrid, pts = [], []
for th in np.linspace(0, np.pi, N, endpoint=False):
lats = []
for ph in np.linspace(0, 2 * np.pi, N, endpoint=False):
p = spher2cart(rmax, th, ph)
intersections = shape.intersectWithLine([0, 0, 0], p) #
if len(intersections):
value = mag(intersections[0])
lats.append(value)
pts.append(intersections[0])
else:
lats.append(rmax)
pts.append(p)
agrid.append(lats)
agrid = np.array(agrid)
grid = pyshtools.SHGrid.from_array(agrid)
clm = grid.expand()
grid_reco = clm.expand(lmax=lmax) # cut "high frequency" components
rmax = 2.0 # line length
x0 = [0, 0, 0] # set object at this position
#############################################################
shape = load(datadir + "pumpkin.vtk").normalize().pos(x0).lineWidth(.1)
show(shape, at=0, N=2, bg='w')
############################################################
# cast rays from the center and find intersections
agrid, pts = [], []
for th in np.linspace(0, np.pi, N, endpoint=True):
lats = []
for ph in np.linspace(0, 2*np.pi, N, endpoint=True):
p = spher2cart(rmax, th, ph)
intersections = shape.intersectWithLine([0, 0, 0], p) # <--------------
if len(intersections):
value = mag(intersections[0])
lats.append(value)
pts.append(intersections[0])
else:
lats.append(rmax)
pts.append(p)
agrid.append(lats)
agrid = np.array(agrid)
############################################################
# Please install pyshtools to continue this example
# Follow instructions at https://shtools.oca.eu/shtools