Most of the files related to user-made content can be found under the game User path.
That path root is located at:
- On Windows
- On Mac
/Users/<username>/Library/Application Support/Colossal Order/Cities_Skylines
- On Linux
- Assets - Assets saved from the Asset Editor are stored here
- ColorCorrections - Custom color corrections look-up tables can be placed in this folder
- Import - All the assets (textures, models) to import custom assets in the Asset Editor are placed here
- Brushes - Custom made brush textures can be placed here
- Heightmaps - Heightmaps to import are placed in this folder, exported heightmaps from the Map Editor also will appear in this folder
- Mods - Base folder for user made code modifications
- Maps - Maps saved from the Map Editor are stored here
- Saves - Save games are stored here
- Snapshots* - Snapshots taken from the Map Editor and the Asset Editor are stored in subfolders named after their unique id
- WorkshopStagingArea** - Steam Workshop content is shown in subfolders here before being uploaded
* - These folders are never automatically cleaned up, that means the more snapshots a user take, the more images and subfolders there will be. It is convenient when working for a long time with multiple maps to preserve older snapshots to be reused. The folder can be deleted manually with no side effects for the game if needs arise.
** - These folders exist only during the time they are needed.
Additionally, the game may use an additional "Temp" folder if needed. The folder is created under Addons and does not require any human interactions.
Cities: Skylines uses an in-house Colossal Raw Asset Package (.crp) file format to store various data. Those packages are containers and can encapsulate any data type, so a .crp file can be a save, a map, a color correction or an asset. The game will output packages in their respective designated place so it is safe to assume a Savegame produced by the game will always be written to the Saves folder. For assets importing, standard image formats such as png, jpg, bmp, tga, dds, raw, r8, r16, and tiff are supported, but depending on the tool you are using those with, only a subset may be available. Please refer to the tool documentation for more details. For geometry/models/meshes, the FBX file format is the only one officially supported.