Joint anchor tool editor script

Hi,

Here's a small editor script to create a custom EditorTool to edit joint anchors with a position gizmo. Not sure if later versions already have something like this built-in, but I'm still on 2020, and this has been sorely missed. It can save a lot of time vs. fiddling with the inspector values. Place this code in a script in Editor folder.

The tool is available when a single gameobject with a joint is selected. There are cases it doesn't properly address (e.g. multiple joint components on a single object seems iffy). FixedJoints expose the anchor in script, but not sure if they are meant to be editable, so the tool is disabled in that case.

Code (CSharp):

1. using UnityEngine;
2. using UnityEditor;
3. using UnityEditor.EditorTools;
4.  
5. /// <summary>
6. /// Editor tool to set joint anchor with a position gizmo.
7. /// </summary>
8. [EditorTool("Joint Anchor Tool", typeof(Joint))]
9. class JointAnchorTool : EditorTool
10. {
11.     GUIContent mIconContent;
12.     GUIStyle mLabelStyle;
13.  
14.     void OnEnable()
15.     {
16.         mIconContent = new GUIContent()
17.         {
18.             image = EditorGUIUtility.FindTexture("AvatarPivot"),
19.             text = "Joint Anchor Tool",
20.             tooltip = "Modify joint anchor position"
21.         };
22.  
23.         mLabelStyle = new GUIStyle(EditorStyles.miniBoldLabel);
24.         mLabelStyle.contentOffset = new Vector2(10f, -25f);
25.         mLabelStyle.normal.textColor = new Color(1f, 1f, 1f, 0.5f);
26.     }
27.  
28.     public override GUIContent toolbarIcon
29.     {
30.         get { return mIconContent; }
31.     }
32.  
33.     public override bool IsAvailable()
34.     {
35.         // Disable for multiple selection and FixedJoints
36.         return Selection.objects.Length == 1 && !(target is FixedJoint);
37.     }
38.  
39.     public override void OnToolGUI(EditorWindow window)
40.     {
41.         Joint joint = target as Joint;
42.  
43.         // Edit own anchor
44.         Handles.matrix = joint.transform.localToWorldMatrix;
45.         Handles.Label(joint.anchor, "Anchor", mLabelStyle);
46.  
47.         EditorGUI.BeginChangeCheck();
48.         Vector3 pos = Handles.PositionHandle(joint.anchor, Quaternion.identity);
49.         if (EditorGUI.EndChangeCheck())
50.         {
51.             Undo.RecordObject(target, "Joint Anchor Position");
52.             joint.anchor = pos;
53.         }
54.  
55.         // Edit connected anchor
56.         if (!joint.autoConfigureConnectedAnchor && joint.connectedBody != null)
57.         {
58.             Handles.matrix = joint.connectedBody.transform.localToWorldMatrix;
59.             Handles.Label(joint.connectedAnchor, "Connected Anchor", mLabelStyle);
60.  
61.             EditorGUI.BeginChangeCheck();
62.             pos = Handles.PositionHandle(joint.connectedAnchor, Quaternion.identity);
63.             if (EditorGUI.EndChangeCheck())
64.             {
65.                 Undo.RecordObject(target, "Joint Connected Anchor Position");
66.                 joint.connectedAnchor = pos;
67.             }
68.         }
69.     }
70. }
71.  

 

You can easily edit multiple joint components on a single object or even on all selected objects by using targets instead of target and do everything in a loop.

Code (CSharp):

1. public override void OnToolGUI(EditorWindow window)
2. {
3.     foreach(Object o in targets)
4.         {
5.         Joint joint = o as Joint;
6.         //...
7.     }
8. }