File size: 3,550 Bytes
406662d | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 | # Copyright (c) 2022-2026, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
# All rights reserved.
#
# SPDX-License-Identifier: BSD-3-Clause
"""
Convert a mesh file to `.obj` using blender.
This file processes a given dae mesh file and saves the resulting mesh file in obj format.
It needs to be called using the python packaged with blender, i.e.:
blender --background --python blender_obj.py -- -in_file FILE -out_file FILE
For more information: https://docs.blender.org/api/current/index.html
The script was tested on Blender 3.2 on Ubuntu 20.04LTS.
"""
import os
import sys
import bpy
def parse_cli_args():
"""Parse the input command line arguments."""
import argparse
# get the args passed to blender after "--", all of which are ignored by
# blender so scripts may receive their own arguments
argv = sys.argv
if "--" not in argv:
argv = [] # as if no args are passed
else:
argv = argv[argv.index("--") + 1 :] # get all args after "--"
# When --help or no args are given, print this help
usage_text = (
f"Run blender in background mode with this script:\n\tblender --background --python {__file__} -- [options]"
)
parser = argparse.ArgumentParser(description=usage_text)
# Add arguments
parser.add_argument("-i", "--in_file", metavar="FILE", type=str, required=True, help="Path to input OBJ file.")
parser.add_argument("-o", "--out_file", metavar="FILE", type=str, required=True, help="Path to output OBJ file.")
args = parser.parse_args(argv)
# Check if any arguments provided
if not argv or not args.in_file or not args.out_file:
parser.print_help()
return None
# return arguments
return args
def convert_to_obj(in_file: str, out_file: str, save_usd: bool = False):
"""Convert a mesh file to `.obj` using blender.
Args:
in_file: Input mesh file to process.
out_file: Path to store output obj file.
"""
# check valid input file
if not os.path.exists(in_file):
raise FileNotFoundError(in_file)
# add ending of file format
if not out_file.endswith(".obj"):
out_file += ".obj"
# create directory if it doesn't exist for destination file
if not os.path.exists(os.path.dirname(out_file)):
os.makedirs(os.path.dirname(out_file), exist_ok=True)
# reset scene to empty
bpy.ops.wm.read_factory_settings(use_empty=True)
# load object into scene
if in_file.endswith(".dae"):
bpy.ops.wm.collada_import(filepath=in_file)
elif in_file.endswith(".stl") or in_file.endswith(".STL"):
bpy.ops.import_mesh.stl(filepath=in_file)
else:
raise ValueError(f"Input file not in dae/stl format: {in_file}")
# convert to obj format and store with z up
# TODO: Read the convention from dae file instead of manually fixing it.
# Reference: https://docs.blender.org/api/2.79/bpy.ops.export_scene.html
bpy.ops.export_scene.obj(
filepath=out_file, check_existing=False, axis_forward="Y", axis_up="Z", global_scale=1, path_mode="RELATIVE"
)
# save it as usd as well
if save_usd:
out_file = out_file.replace("obj", "usd")
bpy.ops.wm.usd_export(filepath=out_file, check_existing=False)
if __name__ == "__main__":
# read arguments
cli_args = parse_cli_args()
# check CLI args
if cli_args is None:
sys.exit()
# process via blender
convert_to_obj(cli_args.in_file, cli_args.out_file)
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