A Unity Editor extension to generate draggable points for vector3 serialized attributes.

DraggablePoint.cs

using System;
using UnityEngine;
#if UNITY_EDITOR
using UnityEditor;
#endif

public class DraggablePoint : PropertyAttribute {}


#if UNITY_EDITOR
[CustomEditor(typeof(MonoBehaviour), true)]
public class DraggablePointDrawer : Editor {

  readonly GUIStyle style = new GUIStyle();

  void OnEnable(){
    style.fontStyle = FontStyle.Bold;
    style.normal.textColor = Color.white;
  }

  public void OnSceneGUI () {
    var property = serializedObject.GetIterator ();
    while (property.Next (true)) {
      if (property.propertyType == SerializedPropertyType.Vector3) {
        var field = serializedObject.targetObject.GetType ().GetField (property.name);
        if (field == null) {
          continue;
        }
        var draggablePoints = field.GetCustomAttributes (typeof(DraggablePoint), false);
        if (draggablePoints.Length > 0) {
          Handles.Label(property.vector3Value, property.name);
          property.vector3Value = Handles.PositionHandle (property.vector3Value, Quaternion.identity);
          serializedObject.ApplyModifiedProperties ();
        }
      }
    }
  }
}
#endif

ExampleBehavior.cs

using UnityEngine;
using System.Collections;

public class ExampleBehavior : MonoBehaviour {
  [DraggablePoint] public Vector3 SpawnPosition;
  public GameObject SpawnableObject;

  public void Spawn() {
    Instantiate(SpawnableObject, SpawnPosition, Quaternion.identity);
  }
}

I realise I'm replying a year and a half later, but I'm trying to adapt this to be able to edit Vector3 arrays in scriptable objects. I'm using SOs to generate spawn points for a mobile game and being able to edit them quickly in the scene view would be useful, rather than doing so in the inspector.

I'm assuming I need to use the OnOpenAsset to access assets as opposed to game objects but I keep hitting brick walls. Anybody managed to do this?