Version: 2017.3
public static SceneAsset playModeStartScene ;

Description

Loads this SceneAsset when you start Play Mode.

If this property is set to a SceneAsset, Unity will load this SceneAsset instead of the scenes currently open in the Editor when you start Play Mode.

using UnityEditor;
using UnityEditor.SceneManagement;
using UnityEngine;

public class TestWindow : EditorWindow { void OnGUI() { // Use the Object Picker to select the start SceneAsset EditorSceneManager.playModeStartScene = (SceneAsset)EditorGUILayout.ObjectField(new GUIContent("Start Scene"), EditorSceneManager.playModeStartScene, typeof(SceneAsset), false);

// Or set the start Scene from code var scenePath = "Assets/Scene3.unity"; if (GUILayout.Button("Set start scene: " + scenePath)) SetPlayModeStartScene(scenePath); }

void SetPlayModeStartScene(string scenePath) { SceneAsset myWantedStartScene = AssetDatabase.LoadAssetAtPath<SceneAsset>(scenePath); if (myWantedStartScene != null) EditorSceneManager.playModeStartScene = myWantedStartScene; else Debug.Log("Could not find scene " + scenePath); }

[MenuItem("Test/Open")] static void Open() { GetWindow<TestWindow>(); } }