Mesh conversion with trimesh

convert_mesh.py

import argparse
import pathlib

import trimesh.exchange.export

if __name__ == "__main__":
    """Mesh conversion script."""

    parser = argparse.ArgumentParser(
        description="Convert a mesh file between different formats.",
    )

    parser.add_argument(
        "-i",
        "--input",
        metavar="PATH",
        type=pathlib.Path,
        help="The input mesh file to convert",
    )

    parser.add_argument(
        "-o",
        "--output",
        metavar="PATH",
        type=pathlib.Path,
        help="The output mesh file",
    )

    parser.add_argument(
        "-t",
        dest="type",
        type=str,
        default=None,
        choices=list(trimesh.exchange.export._mesh_exporters.keys()),
        help="The output format.",
    )

    # Parse the input arguments
    args = parser.parse_args()

    # ================================
    # Post-process the input arguments
    # ================================

    # Expand the input path if not absolute
    args.input = (
        (args.input if args.input.is_absolute() else pathlib.Path.cwd() / args.input)
        .expanduser()
        .absolute()
    )

    # Expand the output path if not absolute
    args.output = (
        (args.output if args.output.is_absolute() else pathlib.Path.cwd() / args.output)
        .expanduser()
        .absolute()
    )

    # Automatically detect the output type if not explicitly specified
    args.type = args.type if args.type is not None else args.output.suffix[1:]

    if args.type not in trimesh.exchange.export._mesh_exporters.keys():
        raise ValueError(f"Unknown output format: '{args.type}'")

    # ===============
    # Import the mesh
    # ===============

    # Load the mesh
    mesh = trimesh.load_mesh(args.input)

    # ===============
    # Export the mesh
    # ===============

    # Remove the output file if it exists
    if args.output.exists():
        args.output.unlink()

    # Create the output file if it doesn't exist
    if not args.output.exists():
        args.output.parent.mkdir(parents=True, exist_ok=True)

    # Export the mesh to the output format
    mesh.export(file_obj=str(args.output), file_type=args.type)

    try:
        trimesh.load_mesh(args.output)
    except Exception:
        msg = "Failed to load the output mesh file. Something might have gone wrong."
        raise RuntimeError(msg)