MetaProcessor

Post-processor that strips AssetOrigin metadata blocks from .meta files of locally imported packages. This removes Asset Store origin tracking from assets that have been re-imported as local packages.

Definition

Namespace: Paragon.Editor.ThirdPartyPackageImporter Assembly: Paragon.Editor.dll

internal class MetaProcessor : Processor

Inherits: Processor

Remarks

When Unity imports assets from the Asset Store, it adds an AssetOrigin section to each .meta file tracking the package source. For local packages (re-imported from a local .unitypackage), this tracking is incorrect and should be removed to prevent Unity from associating the assets with the wrong source.

Regex Pattern

The processor uses a compiled regex to match and remove AssetOrigin blocks:

AssetOrigin:.*(?:\r?\n {2}.*)*(\r?\n)?

This matches:

• The AssetOrigin: header line

• Any continuation lines indented with 2 spaces

• The trailing newline

Item Filtering

• Only processes local packages — returns empty for non-local packages (opposite of FBX/Material processors)

• Filters to non-folder items — all file types, not just specific extensions

• File-level operation — appends .meta to the destination path

Write Encoding

Modified files are written with UTF-8 without BOM (new UTF8Encoding(encoderShouldEmitUTF8Identifier: false)), matching Unity's .meta file convention.

Quick Lookup

Goal	How
What it strips	AssetOrigin: block and all indented sub-properties
When it runs	Only for local packages (IsLocalPackage == true)
File modified	{destinationAssetPath}.meta

Fields

Field	Type	Access	Description
regex	Regex	private readonly	Compiled regex matching AssetOrigin: blocks with indented continuation lines

Methods

OnProcess (protected override)

protected override IEnumerable<ImportPackageItem> OnProcess(ThirdPartyPackage package)

Returns all non-folder items for local packages. Returns empty for remote packages.

OnProcessItem (protected override)

protected override void OnProcessItem(ImportPackageItem packageItem)

Reads the .meta file for the item, strips AssetOrigin blocks via regex, and writes back only if the content changed.

Common Pitfalls

Only processes local packages Unlike the other PostProcessors (FBX, Material) which skip local packages, MetaProcessor only processes local packages. This is the inverse behavior — make sure to understand this distinction.

Meta file must exist If the .meta file doesn't exist (e.g., the asset hasn't been imported yet), the processor silently skips the item. No error is logged.

Regex depends on indentation format The regex expects AssetOrigin sub-properties to be indented with exactly 2 spaces. If Unity changes its .meta file format (e.g., using tabs or different indentation), the regex will not match.

Examples

Before Processing

fileFormatVersion: 2
guid: abc123def456
TextureImporter:
  # ... texture settings ...
AssetOrigin:
  serializedVersion: 1
  productId: 12345
  packageName: com.example.package
  packageVersion: 1.0.0

After Processing

fileFormatVersion: 2
guid: abc123def456
TextureImporter:
  # ... texture settings ...

See Also

• PostProcessors Overview — post-processor subsystem

• FBXProcessor — FBX node renaming

• MaterialProcessor — material URP upgrade