What is the ANM file format?
.anm files are used by Autodesk 3ds Max to store character animation data, most commonly in 3D game asset pipelines and cinematic production.
Files with the .anm extension hold various instructions pertaining to translation and transformation of 3D objects - for example rotations around the X, Y, or Z axis - generated by the Character Studio / Character Assembly workflow inside 3ds Max. .anm files do not contain any 3D model geometry, only their animation instructions. Each file also stores a reference to the character assembly it animates, keeping bone hierarchy and controller keyframe data bundled together.
The format is a proprietary Autodesk binary file, version-dependent and not cross-compatible with other tools without an export step. Modern pipelines typically export to FBX or Alembic for sharing animation between applications; the .bip format handles biped-specific animation within 3ds Max itself. The .anm format remains an internal 3ds Max binary that loads and saves faster than equivalent text-based interchange formats.
Security & safety
RISK: LOWA .anm file is a binary animation data file - not executable and not a malware vector in typical use. It cannot run on its own; it requires 3ds Max to load. Opening one from an untrusted source carries minimal risk, though loading malformed files into 3ds Max could in theory trigger a parser bug.
Format details
in a nutshell- Duke Nukem 3D Sprite Animation - Binary frame-based animation data for enemy/object sprites in the Duke Nukem 3D engine (Build engine, 1996).
- Valve Half-Life / Source engine animation - Some Half-Life / GoldSrc tools use .anm for compiled model animation sequences; main format is .mdl.
- Jazz Jackrabbit 2 scene file - Niche scene/title-set data file from Jazz Jackrabbit 2 (Epic Megagames, 1998); the game's main animation format is J2A.
Programs that open ANM files
Windows1 app
Autodesk 3ds Max
Paid File > Open or the Character menu to load the .anm file as a Character Assembly animation. Technical details
deep spec| File type | Proprietary binary character animation data |
| Developer | Autodesk, Inc. (3ds Max / Character Studio) |
| Encoding | Binary |
| Byte order | Little-endian |
| Container | 3ds Max native binary (Character Assembly) |
| Typical file size | 10 KB - 10 MB |
| Magic bytes | 04 01 00 00 at offset 0 |
| Animation method | Keyframe-based; frame rate set in 3ds Max scene (typically 24, 25, or 30 fps) |
| Stored data | Bone hierarchy, controller keyframes, character assembly structure, and timing data |
| Geometry included | None - stores animation instructions only; 3D model geometry is in separate files |
| Version compatibility | 3ds Max version-dependent; not always cross-version compatible |
| Associated OS | Windows |
| Interchange alternative | FBX or Alembic (.abc) for cross-application use; .bip for biped-only animation within 3ds Max |
| Released | Mid-1990s (Character Studio for 3ds Max) |
| Latest version | Current with shipping versions of Autodesk 3ds Max (2024/2025) |
| Specification | help.autodesk.com |
ANM conversions
Community Q&A
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