A Script To Reverse Your Unity Animation Clip

ReverseAnimation.cs

using UnityEditor;
using UnityEngine;
using System.IO;

public static class ReverseAnimationContext
{

   [MenuItem("Assets/Create Reversed Clip", false, 14)]
   private static void ReverseClip()
   {
       string directoryPath = Path.GetDirectoryName(AssetDatabase.GetAssetPath(Selection.activeObject));
       string fileName = Path.GetFileName(AssetDatabase.GetAssetPath(Selection.activeObject));
       string fileExtension = Path.GetExtension(AssetDatabase.GetAssetPath(Selection.activeObject));
       fileName = fileName.Split('.')[0];
       string copiedFilePath = directoryPath + Path.DirectorySeparatorChar + fileName + "_Reversed" + fileExtension;
       var clip = GetSelectedClip();

       AssetDatabase.CopyAsset(AssetDatabase.GetAssetPath(Selection.activeObject), copiedFilePath);

       clip = (AnimationClip)AssetDatabase.LoadAssetAtPath(copiedFilePath, typeof(AnimationClip));

       if (clip == null)
           return;
       float clipLength = clip.length;
       var curves = AnimationUtility.GetAllCurves(clip, true);
       clip.ClearCurves();
       foreach (AnimationClipCurveData curve in curves)
       {
           var keys = curve.curve.keys;
           int keyCount = keys.Length;
           var postWrapmode = curve.curve.postWrapMode;
           curve.curve.postWrapMode = curve.curve.preWrapMode;
           curve.curve.preWrapMode = postWrapmode;
           for (int i = 0; i < keyCount; i++)
           {
               Keyframe K = keys[i];
               K.time = clipLength - K.time;
               var tmp = -K.inTangent;
               K.inTangent = -K.outTangent;
               K.outTangent = tmp;
               keys[i] = K;
           }
           curve.curve.keys = keys;
           clip.SetCurve(curve.path, curve.type, curve.propertyName, curve.curve);
       }
       var events = AnimationUtility.GetAnimationEvents(clip);
       if (events.Length > 0)
       {
           for (int i = 0; i < events.Length; i++)
           {
               events[i].time = clipLength - events[i].time;
           }
           AnimationUtility.SetAnimationEvents(clip, events);
       }
       Debug.Log("Animation reversed!");
   }

   [MenuItem("Assets/Create Reversed Clip", true)]
   static bool ReverseClipValidation()
   {
       return Selection.activeObject.GetType() == typeof(AnimationClip);
   }

   public static AnimationClip GetSelectedClip()
   {
       var clips = Selection.GetFiltered(typeof(AnimationClip), SelectionMode.Assets);
       if (clips.Length > 0)
       {
           return clips[0] as AnimationClip;
       }
       return null;
   }

}

Hi Pikachuxxxx,

This is an excellent and very helpful tool for reversing animations in Unity - Thank you so much for your contribution!

Unfortunately, the method "AnimationUtility.GetAllCurves()" is obsolete. I adapted your script to use what Unity suggests in its stead. I tried to give you as much credit as possible, because I really didn't do much!

You can find the adapted script here: https://gist.github.com/c1aea8eb4cb95862809fe41489b57257.git

Hope this helps and thanks again for taking the time to make this post a while back!

Best Regards,
Brandon Lyman