Asset Downgrader for Unreal Engine 5
This plugin will downgrade assets for compatibility with 5.0.3 or 4.27 . It works by first upgrading the assets to Source Version (5.3-5.4), and then applying various patches to the .uasset files in order to make them compatible with the TargetVersion (5.0 or 4.27). Do note that features of the newer unreal versions (like nanite on masked materials or new material nodes) can't be ported to the old versions.
How it works :
- First, backup all your assets as this plugin is highly experimental and in certain situations it may corrupt assets or crash the editor if something goes wrong.
- Either have 2 projects, one the SourceVersion and the other with the TargetVersion, or just switch versions for the project you're working with. Integrate the plugin in both projects.
- In the SourceVersion project, select the assets you wish to downgrade.
- From the Downgrader menu choose DowngradeSelectedAssets.
- Either migrate the assets by copy pasting affected files or entire folders with the assets or selecting say a level file, choosing migrate and then choosing a destination Content folder where the project on TargetVersion should reside. Alternatively, switch the version of the project to the TargetVersion
- If TargetVersion is a 5.0.3 project add
[Core.System]
UsePackageTrailer=True
to Config/DefaultEngine.ini
You will get a warning if this is not enabled.
- Open the TargetVersion project and then the downgraded assets. If there were no errors, the assets should open correctly. To be able to migrate these assets to other TargetVersion projects that don't have the Downgrader plugin, the assets need to be resaved (Just select all the assets and use the plugin's SaveSelectedAssets option )
What if I need to downgrade to just 5.2 or 5.1 ?
The flow is identical, but instead of opening the assets in saw 5.0.3 you can open them in 5.1 or 5.2. Do note that in certain situations resaving the assets is still required before opening them in a project without the plugin. You can use the provided "SaveSelectedAssets" option from the plugin to save everything and remove the plugin dependency.
Included with the plugin there are diff files for the SourceVersions (5.3 and 5.4) that you can install with a single click that will apply modifications to the engine sources in order to fix downgrading more asset type (see tutorial)
Can it be downgraded lower than 4.27 ?
Not currently but with enough research & engine modifications definetely possible. Contact me if you have specific needs.
My asset is not supported, can you add support ?
Let me know what kind of assets you're interested. Any asset is implementable but it requires a lot of work.
Known Issues:
- If assets don't appear in packaged builds you forgot to resave the assets ( use the plugin's SaveSelectedAssets option )
- some downgraded scenes' lighting may look too bright in 5.0. You may need to tune ReflectionProbes/Skylight/Directional light intensity and/or rebuild lighting
- if downgrading entire projects, a lot of assets will be loaded into memory, so you may need a lot of RAM sometimes up to 128GB
- if encountering unknown startup crashes due do downgrading a lot of assets, try and downgrade assets one by one, or exclude/delete the offending asset.
- textures with formats like RGBA32F are not downgraded because those formats don't exist in 5.0.
- opening certain maps will sometimes crash. This might be due to masked materials with nanite which are not allowed in 5.0. Try first to open assets individually or remove nanite entirely and then open the map
If you have any issues, errors or crashes don't hesitate to contact me at relativegames7@gmail.com as this plugin is highly experimental.
Please include your editor log found in ProjectName/Saved/Logs/ProjectName.log.