.SI File Extension

2 file types use the .si file extension.

Interleaf Archive

Developer Mindscape
3.6  |  12 Votes

What is a SI file?

An SI file is an archive saved in the Mindscape Interleaf file format, which is a variant of the Resource Interchange Format (RIF). Most SI files contain assets used by the video game LEGO Island. For example, an SI file may contain .WAV music, .BMP graphics, and animation data used in LEGO Island.

More Information

LEGO Island was an action-adventure game available for Windows. Mindscape released LEGO Island in 1997.

The game includes several SI asset packages. These files contain a variety of related game assets whose data is interleaved together. This interleaving makes it easier for LEGO Island to load assets simultaneously. For example, when the game needs to load a line of dialogue and corresponding animation, it can find and read one interleaved section of data from the associated SI file, instead of having to seek, find, and load separate data chunks for each asset.

NOTE: The game Warhammer: Shadow of the Horned Rat also uses SI files.

Common SI Filenames

JUKEBOX.SI - Contains LEGO Island music tracks and dialogue.

NOCD.SI - The only SI file installed in LEGO Island's install directory. The game plays this file's contents when the CD is not inserted.

How to open a SI file

While SI files are not meant to be opened by players, LEGO Island enthusiasts have created utilities that can extract the assets that SI files contain. These utilities include:

  • LEGO Island Music Extractor (LIME)
  • LEGO Island Rebuilder
Open over 400 file formats with File Viewer Plus.Free Download

Programs that open or reference SI files


Softimage Image File

Developer Autodesk
2.6  |  17 Votes

File created by Softimage, a character animation and effects software; stores the graphics for the character in a proprietary format; used for creating 2D or 3D animations.

More Information

Softimage was previously owned by Softimage, Co. The software is now owned and developed by Autodesk.

NOTE: Autodesk discontinued support for Softimage in 2016.

Programs that open SI files

Autodesk Softimage

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