Create a prefab object into the scene exactly where the mouse is pointing

Questions & Answers
1

Hello Guys,I am new to Unity and I would like your help if it is possible.
I made a new window like a level editor and I made a button there called “cube”.
I have a prefab cube and I would like when I click the button “Cube” to go into the scene and start drop prefab cubes exactly where my mouse is pointing.
I tried a lot before such as rays and Event.mousePosition but I couldn’t make it to work.
I guess that is has to be done with a Ray but as I told you I am new and I make something wrong.
I will appreciate any help.

2

You’ve got the right idea. You need to use the Event.mousePosition, use Camera.ScreenPointToRay to convert that into a Ray, and then intersect that Ray with the world. The question is, how do you intersect the ray with the world. If you want to check against collision, use Physics.Raycast. However, it’s possible that this returns no results (like in an empty scene). In that case, you probably want to place the object where the ray intersects the XY plane. To do that, you need to create a Plane object and use it’s Ray intersection method to compute where the ray and plane intersect.

3

Thank you for your Answer.
This is my code of my window:

using UnityEditor;
using UnityEngine;
using System.Collections;

public class LevelEditor : EditorWindow
{

	// Add menu item named "My Window" to the Window menu
	[MenuItem("Window/Level Editor")]
	public static void ShowWindow()
	{
		//Show existing window instance. If one doesn't exist, make one.
		EditorWindow.GetWindow(typeof(LevelEditor));
	}
	
	//It is a method like for display things in our Editor
	void OnGUI()
	{
		//GUILayout.Button("...") creates a button named ... to our Window Editor
		if(GUILayout.Button("Cube"))
		{
			CreateCubes.OnSceneGUI();
		}
	}
}

and this is the code I try to cast the ray:

using UnityEngine;
using System.Collections;
using System;
using UnityEditor;

public class CreateCubes : Editor 
{

	public static void OnSceneGUI()
	{
		Debug.Log("You clicked Button");
		if (Event.current.type == EventType.MouseDown)
	    {
		Ray ray = Camera.main.ScreenPointToRay(Event.current.mousePosition);
		RaycastHit hit = new RaycastHit();
	    if (Physics.Raycast(ray, out hit, 1000.0f))
		{
		Debug.Log(Event.current.mousePosition);
		Vector3 newTilePosition = hit.point;
		Instantiate((GameObject)Resources.Load("prefabs/WholeCube", typeof(GameObject)), newTilePosition, Quaternion.identity);
		}
		else 
		{
		Debug.Log ("Problem with the Physics");
		}
		}
		else {Debug.Log ("Ray didn't get value");}
    }
}

I get the log “You clicked Button” and “Ray didn’t get value” Why?