效果展示：

import os
import sys
import json
import argparse
import numpy as np
import pandas as pd 
import open3d as o3d
from glob import glob

PARTICLE_RADIUS = 0.025

def stl_to_particles(objpath, radius=None):
    if radius is None:
        radius = PARTICLE_RADIUS
    obj = o3d.io.read_triangle_mesh(objpath)
    zhlMoreParticle=1
    particle_area = np.pi * radius**2
    # 1.9 to roughly match the number of points of SPlisHSPlasHs surface sampling
    num_points = int(1.9*zhlMoreParticle * obj.get_surface_area() / particle_area)
    pcd = obj.sample_points_poisson_disk(num_points, use_triangle_normal=True)
    points = np.asarray(pcd.points).astype(np.float32)
    normals = -np.asarray(pcd.normals).astype(np.float32)
    outputPLY = objpath+"{:d}.ply".format(num_points)
    o3d.io.write_point_cloud(outputPLY,pcd)
    print("radius={:}, np={:}".format(radius,num_points))
    return points, normals

def points_vtk_output(name, paticle_all):
    
    with open(name, 'w') as fout:
        n = paticle_all.shape[0]

        fout.write("# vtk DataFile Version 2.0\n\n")
        fout.write("ASCII\n")
        fout.write("DATASET POLYDATA\n")
        fout.write(f"POINTS {n} float\n")

        # x
        for i in range(n):
            fout.write("{:21.14e} {:21.14e} {:21.14e}\n".format(paticle_all['x'][i], paticle_all['y'][i], paticle_all['z'][i]))

        fout.write("VERTICES {} {}\n".format(n, 2 * n))
        for i in range(n):
            fout.write("1 {}\n".format(i))
 

        fout.write("POINT_DATA {}\n".format(n))
        # velocity
        fout.write("VECTORS velocity float\n")
        for i in range(n):
            fout.write("{:21.14e} {:21.14e} {:21.14e}\n".format(paticle_all['nx'][i], paticle_all['ny'][i], paticle_all['nz'][i]))

        # cell id
        fout.write("SCALARS id float 1\n")
        fout.write("LOOKUP_TABLE default\n")
        for i in range(n):
            fout.write("{:d}\n".format(i))

        # radius
        fout.write("SCALARS radius float 1\n")
        fout.write("LOOKUP_TABLE default\n")
        for i in range(n):
            fout.write("{:21.14e}\n".format(PARTICLE_RADIUS))

points, normals = stl_to_particles('wall.stl')
df_particle = pd.DataFrame(data = np.hstack((points, normals)), columns=['x', 'y', 'z' , 'nx', 'ny' ,'nz'] ) 
points_vtk_output('wall.vtk', df_particle)