Python三维网格体素化实例

#!/usr/bin/env python3

# -*- coding: utf-8 -*-

"""

@author: Matthieu Zins

"""

import trimesh

import numpy as np

import os

import argparse

"""

    ======   Voxelize the surface of a mesh   ======

"""

def create_if_needed(folder):

    if not os.path.isdir(folder):

        os.mkdir(folder)

parser = argparse.ArgumentParser(description='Pass object name')

parser.add_argument('input_mesh', type=str)

parser.add_argument('--output_folder', type=str, default="")

parser.add_argument('--resolution', type=int, nargs=3, default=[50, 50, 50],

                    help="resolution_X resolution_Y resolution_Z")

parser.add_argument('--sampling', type=int, default="100000",

                    help="number of points sampled on the mesh")

args = parser.parse_args()

input_mesh_filename = args.input_mesh

object_name = os.path.splitext(os.path.basename(input_mesh_filename))[0]

output_folder = args.output_folder

if len(output_folder) == 0: output_folder = object_name

RES_X, RES_Y, RES_Z = args.resolution

sample_points_count = args.sampling

create_if_needed(output_folder)

mesh = trimesh.exchange.load.load(input_mesh_filename)

# Uniform Points Sampling

pts, _ = trimesh.sample.sample_surface_even(mesh, sample_points_count )

# Save sample points

sampled_points_mesh = trimesh.Trimesh(vertices=pts)

sampled_points_mesh.export(os.path.join(output_folder, object_name + "_resampled_points.ply"))

# Adjust the grid origin and voxels size

origin = pts.min(axis=0)

dimensions = pts.max(axis=0) - pts.min(axis=0)

scales = np.divide(dimensions, np.array([RES_X-1, RES_Y-1, RES_Z-1]))

scale = np.max(scales)

# Voxelize

pts -= origin

pts /= scale

pts_int = np.round(pts).astype(int)

grid = np.zeros((RES_X, RES_Y, RES_Z), dtype=int)

gooRES_X = np.where(np.logical_and(pts_int[:, 0] >= 0, pts_int[:, 0] < RES_X))[0]

gooRES_Y = np.where(np.logical_and(pts_int[:, 1] >= 0, pts_int[:, 1] < RES_Y))[0]

gooRES_Z = np.where(np.logical_and(pts_int[:, 2] >= 0, pts_int[:, 2] < RES_Z))[0]

goods = np.intersect1d(np.intersect1d(gooRES_X, gooRES_Y), gooRES_Z)

pts_int = pts_int[goods, :]

grid[pts_int[:, 0], pts_int[:, 1], pts_int[:, 2]] = 1

# Save voxels

voxel_pts = np.array([[-0.5, 0.5, -0.5],

                      [0.5, 0.5, -0.5],

                      [0.5, 0.5, 0.5],

                      [-0.5, 0.5, 0.5],

                      [-0.5, -0.5, -0.5],

                      [0.5, -0.5, -0.5],

                      [0.5, -0.5, 0.5],

                      [-0.5, -0.5, 0.5]])

voxel_faces = np.array([[0, 1, 2, 3],

                        [1, 5, 6, 2],

                        [5, 4, 7, 6],

                        [4, 0, 3, 7],

                        [0, 4, 5, 1],

                        [7, 3, 2, 6]])

def get_voxel(i, j, k):

    global voxel_pts, voxel_faces

    v = np.array([i, j, k], dtype=float) * scale

    v += origin

    points = voxel_pts * scale + v

    return points, voxel_faces.copy()

points = []

faces = []

fi = 0

for i in range(RES_X):

    for j in range(RES_Y):

        for k in range(RES_Z):

            if grid[i, j, k]:

                p, f = get_voxel(i, j, k)

                points.append(p)

                f += fi

                faces.append(f)

                fi += 8

points = np.vstack(points)

faces = np.vstack(faces)

# Write obj mesh with quad faces

with open(os.path.join(output_folder, object_name + "_voxels.obj"), "w") as fout:

    for p in points:fout.write("v " + " ".join(map(str, p)) + "\n")

    for f in faces+1:fout.write("f " + " ".join(map(str, f)) + "\n")

print(object_name, "done.")

## Usage

python voxelize_surface.py example/chair.obj --output_folder output --resolution 30 30 30 --sampling 10000