Edit settings in Lighting window from editor script

Since you can do it with a runtime/game script (RenderSettings: http://docs.unity3d.com/ScriptReference/RenderSettings.html)

I have to believe you can do it with Editor script, but don't have any experience with it. Have you tried using RenderSettings... references?

Edit: @Phong glad you got that sorted out, I converted comment to Answer.

Hey! Here is a script you need!

Forum post here: http://forum.unity3d.com/threads/access-lighting-window-properties-in-script.328342/#post-2669345

 using System;
 using System.Reflection;
 using UnityEditor;
 using UnityEngine;
 using Object = UnityEngine.Object;
 
 
 public static class LightingSettingsHepler
 {
     public static void SetIndirectResolution(float val)
     {
         SetFloat("m_LightmapEditorSettings.m_Resolution", val);
     }
 
     public static void SetAmbientOcclusion(float val)
     {
         SetFloat("m_LightmapEditorSettings.m_CompAOExponent", val);
     }
 
     public static void SetBakedGiEnabled(bool enabled)
     {
         SetBool("m_GISettings.m_EnableBakedLightmaps", enabled);
     }
 
     public static void SetFinalGatherEnabled(bool enabled)
     {
         SetBool("m_LightmapEditorSettings.m_FinalGather", enabled);
     }
 
     public static void SetFinalGatherRayCount(int val)
     {
         SetInt("m_LightmapEditorSettings.m_FinalGatherRayCount", val);
     }
 
     public static void SetFloat(string name, float val)
     {
         ChangeProperty(name, property => property.floatValue= val);
     }
 
     public static void SetInt(string name, int val)
     {
         ChangeProperty(name, property => property.intValue = val);
     }
 
     public static void SetBool(string name, bool val)
     {
         ChangeProperty(name, property => property.boolValue = val);
     }
 
     public static void ChangeProperty(string name, Action<SerializedProperty> changer)
     {
         var lightmapSettings = getLighmapSettings();
         var prop = lightmapSettings.FindProperty(name);
         if (prop != null)
         {
             changer(prop);
             lightmapSettings.ApplyModifiedProperties();
         }
         else Debug.LogError("lighmap property not found: " + name);
     }
 
     static SerializedObject getLighmapSettings()
     {
         var getLightmapSettingsMethod = typeof(LightmapEditorSettings).GetMethod("GetLightmapSettings", BindingFlags.Static | BindingFlags.NonPublic);
         var lightmapSettings = getLightmapSettingsMethod.Invoke(null, null) as Object;
         return new SerializedObject(lightmapSettings);
     }
 
     public static void Test()
     {
         SetBakedGiEnabled(true);
         SetIndirectResolution(1.337f);
         SetAmbientOcclusion(1.337f);
         SetFinalGatherEnabled(true);
         SetFinalGatherRayCount(1337);
     }
 }
 

Thanks! :)