Folder Structure

The OCA format is a folder, containing an OCA JSON data file with all data about the document (except images), and image files, which can be one of these formats: PNG, openEXR, SVG.

Data file

The OCA data file must be at the root of the OCA folder, and should have the same name.

There must be a single OCA data file in the folder, and it must be at the root.

Metadata file

There may or may not be a metadata file at the root of the OCA folder, which is named after the OCA data file, suffixed with _meta and with the .json extension.

The metadata is separated from the main OCA data file to make it easy for users to strip (or replace) all metadata from the file.

Other files

Other files and folders may be stored as follow, but as the JSON data contains all (relative) paths to all files, that’s not mandatory.

▾ Document_name.oca
    · Document_name.oca
    · Document_name_meta.json
    ▾ Layer_name_1
        · Layer_name_1_00000.png
        · Layer_name_1_00110.png
        · Layer_name_1_00112.png
        · Layer_name_1_00114.png
        · Layer_name_1_00200.png
    ▾ Group_name_2
        ▾ Layer_name_3
            · Layer_name_3_00000.png
            · Layer_name_3_00003.png
        ▸ Layer_name_4
        ▸ Layer_name_5
    ▸ Group_name_6


The .oca file at the root may also use the extension .json.


All layers may be stored in a single subfolder with an arbitrary name (e.g. “content”, “data”, “layers”, “Document”…) instead of directly at the root.