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| 1 | +# Assets migration |
| 2 | + |
| 3 | +Assets migration is a procedure allowing you to export the assets of a project into another unreal engine project. |
| 4 | + |
| 5 | +When triggering it from the editor, you will get a list of packages to export and where to save them. |
| 6 | + |
| 7 | +Here we will see how to automate the task from python |
| 8 | + |
| 9 | +## Step1 getting asset dependencies |
| 10 | + |
| 11 | +An important topic you need to understand, is that you export packages not single assets. Packages are mapped into real files. |
| 12 | + |
| 13 | +Packages can contain multiple assets (albeit highly discouraged). |
| 14 | + |
| 15 | +When we want to migrate an asset we need to get its package and all othe packages referenced by the asset (as an example, a blueprint |
| 16 | +with a StaticMeshComponent, holds a reference to the StaticMesh asset, so weneed to export it to). |
| 17 | + |
| 18 | +The unreal_engine.get_asset_dependencies(package_name) will do the trick: |
| 19 | + |
| 20 | +```python |
| 21 | +import unreal_engine as ue |
| 22 | + |
| 23 | +# get the currently selected asset |
| 24 | +asset = ue.get_selected_assets()[0] |
| 25 | + |
| 26 | +# retrieve the package path |
| 27 | +package_path = asset.get_outermost().get_path_name() |
| 28 | +print(package_path) |
| 29 | + |
| 30 | +def recursive_deps(pkg_path, deps): |
| 31 | + deps.append(pkg_path) |
| 32 | + for _dep in ue.get_asset_dependencies(pkg_path): |
| 33 | + if _dep not in deps: |
| 34 | + if not _dep.startswith('/Engine') and not _dep.startswith('/Script'): |
| 35 | + recursive_deps(_dep, deps) |
| 36 | + |
| 37 | + |
| 38 | +deps = [] |
| 39 | + |
| 40 | +recursive_deps(package_path, deps) |
| 41 | + |
| 42 | +print(deps) |
| 43 | +``` |
| 44 | + |
| 45 | +## Step2: fixing dirty packages |
| 46 | + |
| 47 | +A package is marked as dirty when it has been modified without saving it. In this step we will check each package we need to |
| 48 | +migrate and we will eventually save it: |
| 49 | + |
| 50 | +```python |
| 51 | +for _dep in deps: |
| 52 | + # load the package |
| 53 | + pkg = ue.load_package(_dep) |
| 54 | + # check for dirty packages |
| 55 | + if pkg.package_is_dirty(): |
| 56 | + pkg.save_package() |
| 57 | +``` |
| 58 | + |
| 59 | +## Step3: copying .uasset files in the destination project |
| 60 | + |
| 61 | +This is the last step, we retieve the filename of each package and will copy it in the destination directory. |
| 62 | + |
| 63 | +Full script for migration: |
| 64 | + |
| 65 | +```python |
| 66 | +import unreal_engine as ue |
| 67 | +import os |
| 68 | +from shutil import copyfile |
| 69 | + |
| 70 | +# get the currently selected asset |
| 71 | +asset = ue.get_selected_assets()[0] |
| 72 | + |
| 73 | +# retrieve the package path |
| 74 | +package_path = asset.get_outermost().get_path_name() |
| 75 | +print(package_path) |
| 76 | + |
| 77 | +def recursive_deps(pkg_path, deps): |
| 78 | + deps.append(pkg_path) |
| 79 | + for _dep in ue.get_asset_dependencies(pkg_path): |
| 80 | + if _dep not in deps: |
| 81 | + if not _dep.startswith('/Engine') and not _dep.startswith('/Script'): |
| 82 | + recursive_deps(_dep, deps) |
| 83 | + |
| 84 | + |
| 85 | +deps = [] |
| 86 | + |
| 87 | +recursive_deps(package_path, deps) |
| 88 | + |
| 89 | +print(deps) |
| 90 | + |
| 91 | +destination = 'D:/UdemyCast/Content' |
| 92 | + |
| 93 | +for _dep in deps: |
| 94 | + # check for dirty packages |
| 95 | + pkg = ue.load_package(_dep) |
| 96 | + if pkg.package_is_dirty(): |
| 97 | + pkg.save_package() |
| 98 | + src = pkg.package_get_filename() |
| 99 | + sub = src.split('/Content/', 1)[1] |
| 100 | + dst = os.path.join(destination, sub) |
| 101 | + copyfile(src, dst) |
| 102 | + |
| 103 | +print('asset migrated') |
| 104 | +``` |
| 105 | + |
| 106 | +Ensure the destination directory is a /Content directory in UE4 project |
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