python 输出 STL 文件的质心（重心）
import numpy as np
from stl import mesh # pip install numpy-stl
# Using an existing closed stl file:
your_mesh = mesh.Mesh.from_file('some_file.stl')
volume, cog, inertia = your_mesh.get_mass_properties()
print("Volume = {0}".format(volume))
print("Position of the center of gravity (COG) = {0}".format(cog))
print("Inertia matrix at expressed at the COG = {0}".format(inertia[0,:]))
print(" {0}".format(inertia[1,:]))
print(" {0}".format(inertia[2,:]))
