Where a shell sits: metres above the surface (Earth metres, scaled with the atmosphere like cloud altitudes), a layer top from AtmosphereLayers, or the moon's 'perigee' / 'apogee'.
'perigee'
'apogee'
Where a shell sits: metres above the surface (Earth metres, scaled with the atmosphere like cloud altitudes), a layer top from AtmosphereLayers, or the moon's
'perigee'/'apogee'.