Extracts SH coefficients from light probes, and rebuilds light probes from given SH coefficients.

LightProbeRebuilder.cs

using UnityEngine;
using UnityEditor;
using System.Collections;

public class LightProbeRebuilderWindow : EditorWindow
{
    string text = "Paste extracted coefficients here.";
	float multiplier = 1.0f;

    [MenuItem("Window/Light Probe Rebuilder")]
    static void OpenNewWindow ()
    {
        var window = EditorWindow.GetWindow (typeof(LightProbeRebuilderWindow));
        window.title = "Light Probe Rebuilder";
    }

    string ExtractCoefficients ()
    {
        var probes = LightmapSettings.lightProbes;
        if (probes && probes.count > 0)
        {
            var text = "";
            for (var i = 0; i < 26; i++)
                text += probes.coefficients [i] + ",";
            return text + probes.coefficients [26];
        }
        else
        {
            return "There is no light probe.";
        }
    }

    void RebuildFromInput ()
    {
        var probeGroup = FindObjectOfType (typeof(LightProbeGroup)) as LightProbeGroup;

        if (probeGroup == null)
        {
            var go = new GameObject ("Probes");
            probeGroup = go.AddComponent<LightProbeGroup> ();
        }

        probeGroup.probePositions = new Vector3[]{
            new Vector3 (0, 100, 100),
            new Vector3 (100, 100, 0),
            new Vector3 (-100, 100, 0),
            new Vector3 (0, 200, 0)
        };

        var coeffs = new float[27 * 4];
        var textLines = text.Split (',');
        for (var i = 0; i < 27; i++)
        {
            var coeff = float.Parse (textLines [i]) * multiplier;
            for (var i2 = 0; i2 < 4; i2++)
                coeffs [i + i2 * 27] = coeff;
        }

        Lightmapping.BakeLightProbesOnly ();
        LightmapSettings.lightProbes.coefficients = coeffs;
    }

    void OnGUI ()
    {
        var style = EditorStyles.textField;
        style.wordWrap = true;

        text = EditorGUILayout.TextField ("Coefficients", text, style, GUILayout.ExpandHeight (true));
		multiplier = EditorGUILayout.Slider ("Multiplier", multiplier, 0.1f, 10.0f);

        EditorGUILayout.BeginHorizontal ();

        if (GUILayout.Button ("Rebuild Light Probes"))
            RebuildFromInput ();

        if (GUILayout.Button ("Extract Coefficients"))
            text = ExtractCoefficients ();

        EditorGUILayout.EndHorizontal ();
    }
}