教育現場で使える！無料の日本の街3DデータをUnityに表示するまで #3Dモデル – Qiita

import bpy
import os
import addon_utils
import shutil
import sys
from PIL import Image

# Blenderの特殊なコマンドライン構造に対応
if "--" not in sys.argv:
    print("Usage: blender --background --python import_all_obj.py -- ")
    sys.exit(1)

args = sys.argv[sys.argv.index("--") + 1:]
if len(args)  1:
    print("Usage: blender --background --python import_all_obj.py -- ")
    sys.exit(1)

root_dir = args[0]
addon_utils.enable("io_scene_obj")
output_dir = "./output_unity"
os.makedirs(output_dir, exist_ok=True)
used_textures = set()

# 空白が含まれるファイル名を正規化（スペース→アンダースコア）
def normalize_filenames(root):
    for dirpath, dirnames, filenames in os.walk(root):
        for name in filenames:
            if " " in name:
                old_path = os.path.join(dirpath, name)
                new_name = name.replace(" ", "_")
                new_path = os.path.join(dirpath, new_name)
                os.rename(old_path, new_path)
                print(f"Renamed: {old_path} → {new_path}")

# PNG→JPG変換
def convert_png_to_jpg(png_path):
    jpg_path = os.path.splitext(png_path)[0] + ".jpg"
    if os.path.exists(jpg_path):
        return jpg_path
    try:
        print(f"Converting PNG to JPG: {png_path} → {jpg_path}")
        with Image.open(png_path) as im:
            rgb_im = im.convert("RGB")
            rgb_im.save(jpg_path, "JPEG")
        return jpg_path
    except Exception as e:
        print(f"Failed to convert {png_path} to JPG: {e}")
        return None

# MTLファイルの処理
def fix_mtl_paths(mtl_path, base_dir):
    print(f"Processing MTL file: {mtl_path}")
    with open(mtl_path, "r", encoding="utf-8") as f:
        lines = f.readlines()

    modified = False
    new_lines = []

    for line in lines:
        if line.strip().startswith("map_Kd"):
            parts = line.strip().split(maxsplit=1)
            if len(parts) == 2:
                tex_file = parts[1].strip()
                tex_file = tex_file.replace(" ", "_")  # 一応ここでも置換

                tex_path = None

                # 解決候補パス
                candidates = [
                    tex_file,
                    os.path.abspath(tex_file),
                    os.path.join(root_dir, tex_file),
                    os.path.join(base_dir, tex_file),
                ]

                for candidate in candidates:
                    candidate = os.path.normpath(candidate)
                    if os.path.exists(candidate):
                        tex_path = candidate
                        break

                # PNGならJPGに変換
                if tex_path and tex_path.lower().endswith(".png"):
                    converted = convert_png_to_jpg(tex_path)
                    if converted:
                        tex_path = converted

                # テクスチャ使用記録＋書き換え
                if tex_path and os.path.exists(tex_path):
                    used_textures.add(tex_path)
                    tex_path_fixed = tex_path.replace("\\", "/")
                    if tex_file != tex_path_fixed:
                        print(f"Fixing texture path: {tex_path_fixed}")
                        line = f"map_Kd {tex_path_fixed}\n"
                        modified = True
                else:
                    print(f"Texture file not found: {tex_file}")

        new_lines.append(line)

    if modified:
        with open(mtl_path, "w", encoding="utf-8") as f:
            f.writelines(new_lines)

# 空白ファイル名の事前処理
normalize_filenames(root_dir)

# OBJ 読み込みループ
for dirpath, dirnames, filenames in os.walk(root_dir):
    for file in filenames:
        if file.lower().endswith(".obj"):
            obj_path = os.path.normpath(os.path.join(dirpath, file))
            mtl_path = obj_path.replace(".obj", ".mtl")

            if os.path.exists(mtl_path):
                fix_mtl_paths(mtl_path, dirpath)

            print(f"Importing: {obj_path}")
            bpy.ops.import_scene.obj(filepath=obj_path)

# カメラとライトを削除
for obj in bpy.data.objects:
    if obj.type in ['CAMERA', 'LIGHT' ]:
        bpy.data.objects.remove(obj, do_unlink=True)

for obj in bpy.data.objects:
    if obj.name.lower().startswith("cube"):
        bpy.data.objects.remove(obj, do_unlink=True)

# 統合と回転
print("Joining all imported objects...")
bpy.ops.object.select_all(action='SELECT')
objs = [obj for obj in bpy.context.selected_objects if obj.type == 'MESH']
if objs:
    bpy.context.view_layer.objects.active = objs[0]  # アクティブに設定
    bpy.ops.object.mode_set(mode='OBJECT')
    bpy.ops.object.join()

    # -90度回転（X軸）
    obj = bpy.context.active_object
    obj.rotation_euler[0] -= 1.5708
else:
    print("No mesh objects to join or rotate.")


# FBX出力
print("Exporting to FBX...")
fbx_output = os.path.join(output_dir, "output.fbx")
bpy.ops.export_scene.fbx(
    filepath=fbx_output,
    use_selection=False,
    apply_unit_scale=True,
    bake_space_transform=True,
    axis_forward='-Z',
    axis_up='Y'
)

# テクスチャコピー
for tex_path in used_textures:
    if os.path.exists(tex_path):
        try:
            shutil.copy(tex_path, output_dir)
            print(f"Copied texture: {tex_path}")
        except Exception as e:
            print(f"Failed to copy {tex_path}: {e}")

 blender --background --python import_all_obj.py -- ./temp