util/obj_io.py

import os
import numpy as np
from scipy.spatial.transform import Rotation as R


def load_obj(filename):
    vertices = []
    faces = []

    with open(filename, 'r') as fp:
        for line in fp:
            line_split = line.split()

            if not line_split:
                continue

            elif line_split[0] == 'v':
                vertices.append([line_split[1], line_split[2], line_split[3]])

            elif line_split[0] == 'f':
                vertex_indices = [s.split("/")[0] for s in line_split[1:]]
                faces.append(vertex_indices)

    vertices = np.array(vertices, dtype=np.float32)
    faces = np.array(faces, dtype=np.int32) - 1

    return vertices, faces


def save_obj(filename, vertices, faces):
    os.makedirs(os.path.dirname(filename), exist_ok=True)

    with open(filename, 'w') as fp:
        for v in vertices:
            fp.write('v %f %f %f\n' % (v[0], v[1], v[2]))

        for f in (faces + 1):  # Faces are 1-based, not 0-based in obj files
            fp.write('f %d %d %d\n' % (f[0], f[1], f[2]))

    print("Saved:", filename)