Search public documentation:


Interested in the Unreal Engine?
Visit the Unreal Technology site.

Looking for jobs and company info?
Check out the Epic games site.

Questions about support via UDN?
Contact the UDN Staff

UE3 Home > Commandlets > CompressAnimations Commandlet

CompressAnimations Commandlet


The CompressAnimations commandlet is the equivalent of choosing 'automatic' compression in the editor, but it goes through all the available packages, and animations. It tries all compression schemes, with various parameters, and picks the best one. Best being the smallest size given the allowed error threshold.


To run this commandlet, from a command prompt window, navigate to the UnrealEngine3\Binaries directory.


The syntax is as follows:

[GameName].exe compressanimations [parameters]


The CompressAnimations commandlet has several command line parameters that can be specified to determine how it functions.

  • SKIPCINES - If this parameter is specified, any animations sequences containing the word 'Cine' will be skipped. This can help to preserve the visual fidelity of cinematic animations.

  • SKIPLONGANIMS - If this parameter is specified, any animations sequences containing more than 300 frames will be skipped in order to make the process faster. Longer animations can take a while to process.

  • RESETCOMPRESSION - If this parameter is specified, animation sequences should be recompressed from scratch rather than trying to beat current compression. This will ensure quality standard is met, as current compression could compress well but be considered too destructive in terms of quality (by the commandlet error theshold standard, and potential updates to the compressors since the animation was originally compressed).

  • CLEARNOCOMPRESSIONOVERRIDE - If this parameter is specified, any animation sequence marked as 'bDoNotOverrideCompression'will have that flag reset and the animation will be recompressed anyways.

  • VERBOSE - If this parameter is specified, output details of the compression status to log file.

  • SKIPREADONLY - If this parameter is specified, packages marked read-only will be skipped. This allows the process to be sped up by only checking out the desired package(s) for recompression while leaving all the others read-only.

  • AUTOCHECKOUTPACKAGES - If this parameter is specified, the comandlet automatically tries to check out packages as needed.

INI Properties

There are several properties found in the [AnimationCompression] category of the BaseEngine.ini config file that control how animation compressing in general and the CompressAnimations commandlet function.

  • CompressCommandletVersion - The commandlet only recompresses new animations, i.e. animations compressed with a version number lower than this setting. Increasing this number will force the commandlet to recompress ALL animations.

  • DefaultCompressionAlgorithm - Specifies the name of the Compression Scheme to use by default when importing an animation.

  • TranslationCompressionFormat - Specifies the default translation compression format to use with above default scheme. This value is the index of the format in the AnimationCompressionFormat enum.

  • RotationCompressionFormat - Specifies the default rotation compression format to use with above default scheme. This value is the index of the format in the AnimationCompressionFormat enum.

  • AlternativeCompressionThreshold - Specifies the default Error Tolerance to use when compressing animations. Any compression method that results in an error beyond this value will be rejected.

  • bOnlyCheckForMissingSkeletalMeshes - If TRUE, the commandlet will not recompress animations and only check content to make sure a matching skeletal mesh can be found. This is needed to rebuild the animation data from local to mesh space.

  • KeyEndEffectorsMatchName - Array of names to match in Bone Name array. Those bones will be considered key effectors, and special care will be taken to reduce error on those. defaults are "IK", "eye", "weapon", "hand", "attach", "camera".