| identifier | A Unique identifier associated to this Asset. |
| asset | The Unity Object that is the sub-Asset. |
| thumbnail | An optional 2D texture to use as the thumbnail for the Asset. |
Set's the main Asset to the result of the import operation.
This method can only be called once per import opperation and must be called. Returning without setting a main Asset will result in a failed import opperation
This method allows you to specify which Asset is the main Asset during the import process. Any other Assets which are created during the import will become sub-Assets to this Asset. For example, when importing an FBX file, any Materials and Textures imported from the file become sub-Assets. You must call this method during the OnAssetImport process.
Note:
You must make sure that your importer creates a unique identifier for each Asset.
You must also make sure that your code regenerates the same identifier each time the file is re-imported, even if sub-Assets have been modified. This allows Unity to keep track of which old sub-Assets have been modified when a file is re-imported, and therefore which should be replaced by the corresponding new versions of the same sub-Assets.
The identifier only needs to be unique within the context of the Asset file and not globaly unique across your whole project.