[Mecanim] How do you modify blend trees in synced layers?

When syncing Mecanim layers, the synced states have no motion assigned to them. For normal states, this is good because I can drag and drop a new animation state, but how do you replace a blend tree in the synced layer?

When selecting the blend tree on the synced layer, in the Inspector it shows you that there is no blend tree assigned to it. So then how do I change the animations in that blend tree?

 

Sync layer do not recreate all the blend tree hierarchy for you, because you can choose that for this sync layer this state is not a blend tree but only one clip.

If you want to recreate a blend tree, you can right click on the state in the graph view and click on Create New Blend Tree in state or by script find out the original blend tree, make a copy and assign it to the sync layer state.

 

Can we get an example of copying the original blend tree please?

UnityEditor.Animations.AnimatorControllerLayer.GetOverrideMotion returns the overridden motion but SetOverrideMotion does nothing.

Thanks in advance!

 

Bumping since I'm interested in the method of copying the blend tree... I tried to manually change values in the controller file but Unity didn't like it...
Maybe Blend Trees should also be saved as assets, so it would be easier to reuse/duplicate them...

 

A hail mary bump for a script example of how to do this.

"... or by script find out the original blend tree, make a copy and assign it to the sync layer state."

Not being able to do this makes layers unusable for me :|.

 

Here's where I got. Perhaps @Mecanim-Dev can tell me where I've gone wrong.

The below successfully fixed the non-copying / syncing blendtrees in the new layer. But, ultimately doesn't solve the problem b/c it syncs them while breaking override. Meaning, that if I update a blend tree on layer 1, it updates the layer 0 blend tree. Is there a way around this?

Code (csharp):

1.  
2. using UnityEngine;
3. using UnityEditor;
4. using System.Collections;
5. using System.Reflection;
6. using UnityEditor.Animations;
7.  
8. public class DuplicateAnimatorLayer : EditorWindow
9. {
10. UnityEditor.Animations.AnimatorController source;
11.     string layerToCopy_Value;
12.     int layerToFix;
13.  
14. [MenuItem("2Ton/Duplication Animator Layer")]
15. static void GetWindow()
16. {
17. EditorWindow.GetWindow(typeof(DuplicateAnimatorLayer));
18. }
19.  
20. void OnGUI()
21. {
22. source = EditorGUILayout.ObjectField("Source", source, typeof(AnimatorController),
23.             true, GUILayout.ExpandWidth(true)) as AnimatorController;
24.  
25. layerToFix = EditorGUILayout.IntField("Layer to Fix: ", layerToFix);
26.  
27. // EditorGUILayout.TextField("Object Name: ", Selection.activeGameObject.name);
28.  
29. if (GUILayout.Button("Copy", GUILayout.ExpandWidth(true), GUILayout.Height(24)))
30. {
31. if (source != null && layerToFix != 0)
32.             {
33. copy();
34.             }
35. }
36. }
37.  
38.     void copy()
39.     {
40.         AnimatorStateMachine baseStateMachine = source.layers[0].stateMachine;
41.  
42. // as per unity documentation: https://docs.unity3d.com/ScriptReference/Animations.AnimatorController-layers.html
43. // "It's important to note that the AnimatorControllerLayer are returned as a copy. The array should be set back into the property when changed."
44.         // so we need to explicitly get the controller's layers, then below we update their motions, then we explicitly update them
45. AnimatorControllerLayer[] layers = source.layers;  
46.  
47. // go through all the sub-state machines
48. for (int i = 0; i < baseStateMachine.stateMachines.Length; i++)
49. {
50.             AnimatorStateMachine stateMachine = baseStateMachine.stateMachines[i].stateMachine;
51.  
52.             // update motions
53. for (int m = 0; m < stateMachine.states.Length; m++)
54. {
55.                 // we only care about blend trees, they are the ones that don't sync
56. if (stateMachine.states[m].state.motion.GetType() == typeof(BlendTree))
57. {
58. AnimatorState state = stateMachine.states[m].state;
59. UnityEngine.Motion motion = layers[layerToFix].GetOverrideMotion(state);
60.  
61. if (motion == null)
62. {
63. Debug.Log("Overriding: " + state.name);
64. layers[layerToFix].SetOverrideMotion(state, state.motion);
65. }
66. }
67.             }
68.  
69.             // explicitly update the controller's layers so the copy gets updated
70.             source.layers = layers;
71. }
72.     }
73.  
74.     // I wish this worked...
75.  
76.     // if (stateMachine.states[m].state.motion.GetType() == typeof(BlendTree))
77.     // {                  
78.     //  AnimatorState state = stateMachine.states[m].state;
79.     //  UnityEngine.Motion motion = layers[layerToFix].GetOverrideMotion(state);
80.  
81.     //  if (motion == null)
82.     //  {
83.     //      BlendTree baseBlendTree = state.motion as BlendTree;
84.     //      BlendTree newBlendTree = new BlendTree();
85.  
86.     //      SerializedObject SO = new SerializedObject(newBlendTree);
87.     //      SerializedProperty SP = SO.GetIterator();
88.  
89.     //      SP = SO.FindProperty("m_UseAutomaticThresholds");
90.     //      SP.boolValue = false;
91.     //      SO.ApplyModifiedProperties();
92.  
93.     //      newBlendTree.blendParameter = baseBlendTree.blendParameter;
94.     //      newBlendTree.blendType = baseBlendTree.blendType;
95.  
96.     //      for (int j = 0; j < baseBlendTree.children.Length; j++)
97.     //      {
98.     //          newBlendTree.AddChild(baseBlendTree.children[j].motion, baseBlendTree.children[j].threshold);
99.     //      }
100.  
101.     //      for (int j = 0; j < baseBlendTree.children.Length; j++)
102.     //      {
103.     //          UnityEditor.Animations.ChildMotion[] newChildren = newBlendTree.children;
104.     //          newChildren[j].timeScale = baseBlendTree.children[j].timeScale;
105.     //          newChildren[j].position = baseBlendTree.children[j].position;
106.     //          newChildren[j].threshold = baseBlendTree.children[j].threshold;
107.     //          newChildren[j].directBlendParameter = baseBlendTree.children[j].directBlendParameter;
108.     //          newBlendTree.children = newChildren;
109.     //      }
110.  
111.     //      motion = newBlendTree;
112.  
113.     //      Debug.Log("Overriding: " + state.name);
114.     //  }
115.     // }
116. }
117.  

 

They can be saved as asset and reused.

This is not something that a lot of user are aware of but statemachine and blend tree are asset that can be saved. In the normal editor workflow they are embedded into the controller asset.
But it also have a side effect if you share a blend tree it does mean that if you change it, it will also change all other reference. That exactly what @v2-Ton-Studios is experiencing.

The best way to create a duplicate of the original blend tree is to use Object.Instantiate
https://docs.unity3d.com/ScriptReference/Object.Instantiate.html

 

I'll dig into this in a few hours, but are you saying that if I use Instantiate in my above code, parameterize so it matches the "base blend tree", and then pass it in as

Code (csharp):

1. SetOverrideMotion (state, instantiatedBlendTree);

... it should work i.e. it would be a true copy, not a reference?

 

Had to try this now... . Using Instantiate makes no difference...

Code (csharp):

1.  
2. if (motion == null)
3. {
4.     BlendTree baseBlendTree = state.motion as BlendTree;
5.     BlendTree newBlendTree = Instantiate <BlendTree> (baseBlendTree);
6.  
7.     // feels like this is the issue. SetOverride "syncs" the blendtrees?
8.     layers[layerToFix].SetOverrideMotion(state, newBlendTree);
9.  
10.     Debug.Log("Overriding: " + state.name);
11. }
12.  

What am I missing here?

The above still results in what seems like a reference between baseBlendTree "Layer0.Foo" and newBlendTree "Layer1.Foo"... .

TIA!

 

hard to tell without debugging the code, I can tell you that we have unit test covering this area and it does work so there is something specific to you're project.

One thing you can do is force your asset serialization to text mode, then open up you're controller asset file and look at what the file look like before and after you're operation.

Each object serialized into the file have a unique ID, something like this:
--- !u!91 &9100000
AnimatorController:


Find the animator state that you are trying to edit, you should have two: one for the base layer and one for the sync layer and check for m_Motion field
--- !u!1102 &1102000010750584734
AnimatorState:
...
m_Motion: {fileID: 7400000, guid: 1d531f81c90784a79b0591821aa8875d, type: 2}

the two animator state should have a unique id for the motion, if they are the same then it does mean that they reference the same object.

or you could you log a bug with you're script ? we will investigate

 

Okay good to know that it should work.

I'll investigate a bit more and see what I find, file a bug if needed. Thanks.

 

How? They don't show up as assets in the asset folder, nor is there any "save as" option as far as I can see for blendtrees.

 

I can only be done with scripting, so you need to write some code to save them as asset

you need to use the following function, also the extension of the file need to be .asset
https://docs.unity3d.com/ScriptReference/AssetDatabase.CreateAsset.html

 

Thanks, will try that!

 

Ok, I've written a quick script to make a duplicate of a selected blendtree and save it as an asset, as Mecanim-Dev suggested. Make sure you actually have a blendtree selected (for the Selection.activeObject as Blendtree to work).

Code (CSharp):

1. using UnityEditor;
2. using UnityEngine;
3. using UnityEditor.Animations;
4.  
5. public class CreateBlendtreeAsset : MonoBehaviour {
6.  
7.     [MenuItem("AnimTools/GameObject/Create Blendtree")]
8.     static void CreateBlendtree()
9.     {
10.      
11.         BlendTree BT = Selection.activeObject as BlendTree;
12.  
13.         BlendTree BTcopy = Instantiate<BlendTree>(BT);
14.         AssetDatabase.CreateAsset(BTcopy,  ("Assets/" + BT.name + ".asset"));
15.     }
16. }
17.  

 

nice!

you should use the following function though to generate a unique asset path.
https://docs.unity3d.com/ScriptReference/AssetDatabase.GenerateUniqueAssetPath.html

 

Like this you mean?

Code (CSharp):

1. public class CreateBlendtreeAsset : MonoBehaviour {
2.  
3.     [MenuItem("AnimTools/GameObject/Asset from Blendtree")]
4.     static void CreateBlendtree()
5.     {
6.      
7.         BlendTree BT = Selection.activeObject as BlendTree;
8.  
9.         BlendTree BTcopy = Instantiate<BlendTree>(BT);
10.  
11.         AssetDatabase.CreateAsset(BTcopy, AssetDatabase.GenerateUniqueAssetPath("Assets/" + BT.name + ".asset"));
12.     }
13. }

[edit] earlier mentioned error seemed to have vanished after windows restart. So never mind that.

 

Hmmm

(The asset is successfully made, I should note.)
is it: https://issuetracker.unity3d.com/is...throws-pointer-errors-and-deletes-transitions ???

 

Here's a GUI version that works pretty well. Select a state in your animator, the script will find the BlendTree and select it for you based on the state's "motion" value.

Code (CSharp):

1. using UnityEditor;
2. using UnityEngine;
3. using UnityEditor.Animations;
4.  
5. public class CreateBlendtreeAsset : EditorWindow
6. {
7.     BlendTree _blendTree;
8.     AnimatorState _animatorState;
9.  
10.     string _motionName, _newName, _createPath;
11.  
12.     [MenuItem("Window/Duplicate Blendtree")]
13.     public static void ShowWindow()
14.     {
15.         //Show existing window instance. If one doesn't exist, make one.
16.         EditorWindow.GetWindow(typeof(CreateBlendtreeAsset));
17.     }
18.  
19.     void OnGUI()
20.     {
21.         GUILayout.Label("Base Settings", EditorStyles.boldLabel);
22.  
23.         EditorGUILayout.BeginHorizontal();
24.         GUILayout.Label("BlendTree");      
25.         _blendTree = EditorGUILayout.ObjectField(_blendTree, typeof(BlendTree), true) as BlendTree;
26.         EditorGUILayout.EndHorizontal();
27.  
28.         if (_blendTree)
29.         {
30.             EditorGUILayout.BeginHorizontal();
31.             GUILayout.Label("BlendTree");
32.             EditorGUILayout.LabelField(_motionName);
33.             EditorGUILayout.EndHorizontal();
34.  
35.             EditorGUILayout.BeginHorizontal();
36.             GUILayout.Label("New Name");
37.             _newName = EditorGUILayout.TextField(_newName);
38.             EditorGUILayout.EndHorizontal();
39.  
40.             EditorGUILayout.BeginHorizontal();
41.             GUILayout.Label("Create Path");
42.             _createPath = EditorGUILayout.TextField(_createPath);
43.             EditorGUILayout.EndHorizontal();
44.  
45.             if (GUILayout.Button("Duplicate BlendTree"))
46.             {
47.                 int canRun = 0;
48.  
49.                 if (_newName == null || _newName == "")
50.                 {
51.                     ShowNotification(new GUIContent("Provide a Name for BlendTree"));
52.                 }
53.                 else
54.                 {
55.                     canRun++;
56.                 }
57.  
58.                 if (_createPath == null || _createPath == "")
59.                 {
60.                     ShowNotification(new GUIContent("Provide a path for BlendTree"));
61.                 }
62.                 else
63.                 {
64.                     canRun++;
65.                 }
66.  
67.                 if (canRun == 2)
68.                 {
69.                     BlendTree BTcopy = Instantiate<BlendTree>(_blendTree);
70.  
71.                     AssetDatabase.CreateAsset(BTcopy, AssetDatabase.GenerateUniqueAssetPath(_createPath + _newName + ".asset"));
72.                 }
73.             }
74.         }
75.         else
76.         {
77.             setBlendTree();
78.         }  
79.     }
80.  
81.     void Update ()
82.     {
83.         setBlendTree();
84.     }
85.  
86.     private void setBlendTree()
87.     {
88.         AnimatorState AS = Selection.activeObject as AnimatorState;
89.  
90.         if (AS != null && AS != _animatorState && AS.motion is BlendTree)
91.         {
92.             _animatorState = AS;
93.             _motionName = _animatorState.name;
94.  
95.             _blendTree = _animatorState.motion as BlendTree;
96.         }
97.     }
98. }
99.  

 

Nice, will give it a try!

 

Sadly coming back to this, again... :|... this only works for top level BlendTrees... the ones nested under sub-state machines.

BlendTrees as values within BlendTrees don't seem to be copy'able AND they seem to be passed by reference not value.

Concrete example...

BlendTree: Run

--> Backwards (Motion)
--> Forward (BlendTree)

--> Sneak (Motion)
--> Normal (BlendTree)

--> Incline (Motion)
--> Flat (Motion)
--> Decline (Motion)​

--> Wounded (Motion)
​

Forward and Normal, highlighted above appear to be passed by reference... if I make a new animator layer 'Torch', I cannot override layer Base > Normal > Flat with layer Torch > Normal > Flat_Torch because replacing 'Flat' with 'Flat_Torch' causes the Flat "slot" to be updated in all copies of the BlendTree.

I also don't seem to be able to separately copy the nested BlendTrees (Forward and Normal) in the above example.

1, What am I missing here?

2, Is there a "deep copy" I can do of a BlendTree?

3, What's the rationale for making animator layers so difficult to use with BlendTrees?

Thanks in advance,

S

 

I made an editor extension that encapsulates a lot of the craziness you are experiencing here. It has support for duplicating and editing blend trees in synced states, state machines and layers with undo/redo. It displays the entire animator controller hierarchy as a tree view and even has drag/drop support for rearranging blend trees and animations.

Saving blend trees as an asset in the project has a ton of really nasty side effects, I'm not even sure what the runtime would do if you added the same blend tree to multiple states in an animator controller. There are also other issues like parameters potentially not matching between blend tree assets and controllers they are being added to. I suspect this is why it isn't something that can be done through the Unity UI by default. Deep copying of blend trees really has to be done by hand one property at time, recursively populating children, and you have to be careful with the asset book keeping especially when dealing with synced layers.

The code for this is all available in my asset if you want to check it out here: https://assetstore.unity.com/packages/tools/animation/anim-tree-editor-161217

 

Would you let me know how to do this via editor?
I want to assign motions in which I created a blentree in sync layer.

I know how to create and assign a blentree in another layer such as Base layer,
but i don't know how I can assign a blendtree in sync layer.

Doc does not explain enough about this and I cannot find any information on any forum.
This is the most pain point on game development using Unity. No information...

Why do we have to find any Unity development information on Internet? Shouldn't it be possible to browse the Unity doc and be able to find any just like Microsoft does?