AnimationUtility.SetEditorCurve

static function SetEditorCurve (clip : AnimationClip, relativePath : String, type : Type, propertyName : String, curve : AnimationCurve) : void

Description

Unity automatic combines position curves, scale curves, rotation curves internally.

Thus transform curves always get combined and their keyframes is always the union of all keyframe points. In the Editor AnimationClip's let you specify special editor curves which do not get combined, thus it lets the user edit curves in a more intuitive way.