Formats/IQM

Tools

See Tools/IQM.

Inter-Quake Model

Note

IQM is the recommended model and animation format for the Dæmon engine and the Unvanquished game.

Bone-based model and skeletal animation format

The Inter-Quake Model (IQM) format was developed by Lee Salzman (aka eihrul) as a more modern alternative to the formats popularly used in the open-source community prior to its introduction.

The .iqm files are binary files.

The .iqe files are text counterpart. Unvanquished stores .iqe files in asset source repositories and ships .iqm files in .dpk archives.

Both IQM and IQE files can embed models with bones and skeletal animations.

Adoption

IQM format is popular in free open source games, mods and free open source game engines like Cube 2: Sauerbraten, Red Eclipse/Blue Nebula, Xonotic (DarkPlaces), Alien Arena, Warsow/Warfork (QFusion), Unvanquished (Dæmon), Ya3dag, FTEQW, ioquake3, and others. It became a de-facto standard for such free open source gaming projects.

IQM format is fully supported in Unvanquished workflow : in engine, asset build tools, level editor, map compiler, etc.

Advantages of IQM over MD5

MD5 format (.md5mesh/.md5anim) was the skeletal model and animation format used by Doom 3, which is also supported by the Dæmon Engine alongside IQM (MD5 was implemented first in XreaL, then IQM was implemented in Dæmon).

We recommend using IQM when possible. Advantages of IQM over MD5 are:

• Triangle adjacency data;
• Non-uniform joint scaling;
• Variable vertex attributes:
  • Position (equivalent to MD2 and MD3 style of animation);
  • Texture coordinates;
  • Normals;
  • Tangents;
  • Weights;
  • Colors;
• Animation and model files may be combined (if desired);
• A binary (“compiled”) format is available (no text parsing at run time).

Specification

• IQM Homepage:
  http://sauerbraten.org/iqm/
• IQM Binary format specification:
  http://sauerbraten.org/iqm/iqm.txt
• IQE Plain-text format specification:
  http://sauerbraten.org/iqm/iqe.txt
• IQM development kit and reference implementation by Lee Salzman:
  https://github.com/lsalzman/iqm

Recommended tool

The recommended tool to convert models to IQM format is Iqmtool.

Implementation

Note

The Dæmon engine loads binary IQM format, the text-based IQE format is used in UnvanquishedAssets source repositories.

Dæmon developer gimhael submitted a patch in 2011 to the ioquake3 bug tracker. Later in 2013, gimhael also implemented IQM in Dæmon engine as well.