An XAF file is most commonly an XML-based animation format used in 3D workflows, often as a 3ds Max or Cal3D XML animation file, and its role is to store motion data rather than full characters or scenes, so opening it in a text editor like Notepad shows structured tags and numbers that define keyframes, timing, and bone transforms without actually “playing,” meaning it holds the choreography of animation tracks but omits meshes, textures, materials, lights, or cameras and assumes a compatible rig already exists.

When dealing with an XAF file, “opening” it typically requires loading it into the correct 3D software—such as 3ds Max’s animation system or a Cal3D workflow—and mismatched bone structures can cause twisting or incorrect motion, so a fast identification method is searching the top of the file in a text editor for “Cal3D” or 3ds Max/Biped/CAT references to spot which importer it belongs to and what rig should accompany it.

An XAF file is focused on animation data rather than complete character assets, typically holding timelines, keyframes, and tracks that drive bone rotations or other transforms tied to specific bone names or IDs, often with interpolation curves for smooth motion, and depending on the pipeline it may store one animation or many while always defining skeletal movement over time.

An XAF file is not designed to carry the visual parts of an animation, meaning no meshes, textures, materials, or scene items such as lights or cameras, and it often doesn’t supply a full rig definition, expecting the software to already have the right skeleton, making the file feel incomplete by itself—like having choreography but no actor—and causing issues when imported into rigs with different naming, hierarchy, orientation, or proportions, which can twist or misalign the motion.

To determine the XAF’s origin, the fastest move is to look at it as a clue file by opening it in Notepad or Notepad++ and checking whether it’s readable XML, because structured tags imply an XML animation format while random symbols may be binary, and if readable, scanning the header or using Ctrl+F for Max, Biped, CAT, Autodesk, or familiar bone names can highlight a 3ds Max–style animation pipeline.

If the content contains clear “Cal3D” references or tag patterns that align with Cal3D animation structures, it’s almost certainly Cal3D XML needing corresponding skeleton/mesh files, while abundant transform tracks and rig-mapped identifiers indicate a 3ds Max origin, and a streamlined runtime-friendly layout tends to reflect Cal3D, making related assets and the first portion of the file useful context clues for verifying the exporter.