Spring supports reading from zlib zip and non-solid 7zip files. The filenames for these compression types must be .SDZ for zlib and .SD7 for 7zip respectively. They are standard files, just with different extensions for Spring. Here's a list of all filetypes supported by Spring; a higher read order means the contents of a file of that extension will take priority over files of a lower read order.
|Read Order||File Extension||Compression Method||Description|
|1||SD7||Non-Solid 7zip||A 7zip file with the extension changed to .SD7. 7zip compressed archives generally have the highest compression (and therefore lowest filesizes). Files of this type are read first.|
|2||SDZ||ZLIB ZIP||A zlib ZIP file with the extension changed to .SDZ. Maps and mods alike can be stored in these files. These are read second.|
The best tools to use to view the contents of a compressed Spring file, and to pack and unpack the contents of such a file are:
- WinRAR to view, browse, extract, and pack SDZ files, or to browse SD7 files.
- 7zip to view, browse, extract, and pack SD7 files.
For the internal file structure of a Spring package, see Gamedev:Structure.