Convert a 3D file to binary PLY format with assimp and the Python plyfile package.

to_plyb.py

#!/usr/bin/env python3

import os
import subprocess
import sys
import tempfile
from plyfile import PlyData


def convert_to_ply(input_file):
    with tempfile.NamedTemporaryFile(delete=False, suffix='.ply') as tmp_file:
        tmp_file.close()
        subprocess.run(['assimp', 'export', input_file, tmp_file.name], check=True)
        return tmp_file.name


def convert_ascii_to_binary_ply(input_path, output_path):
    ply_data = PlyData.read(input_path)
    ply_data.text = False

    with open(output_path, 'wb') as output_file:
        ply_data.write(output_file)


def main():
    if len(sys.argv) != 3:
        print('Usage: python3 to_plyb.py infile.glb outfile.plyb')
        sys.exit(1)

    infile = sys.argv[1]
    outfile = sys.argv[2]

    if not os.path.exists(infile):
        print(f'Error: {infile} does not exist.')
        sys.exit(1)

    try:
        ascii_ply = convert_to_ply(infile)
        convert_ascii_to_binary_ply(ascii_ply, outfile)
        print(f'Successfully converted {infile} to binary PLY {outfile}')
    finally:
        if 'ascii_ply' in locals() and os.path.exists(ascii_ply):
            os.remove(ascii_ply)


if __name__ == '__main__':
    main()