Here is the code for the container object:
#local atmos_object = difference
{
merge
{
cylinder {+z*(city_length/2), -z*(city_length/2), city_radius}
Spheroid(+z*(city_length/2),
<inner_shell_radius3,inner_shell_radius3,inner_shell_bulge>)
Spheroid(-z*(city_length/2),
<inner_shell_radius3,inner_shell_radius3,inner_shell_bulge>)
hollow
}
hollow
material {atmos_material}
}
