Instantiate gameobject on mouseclick from the top down perspective

Hi, I'm making a 3d top down game and I want my character instantiate gameobject on mouse click.

The problem is that when I create a game object the gameobject is not created in the position I want, the object is created in the air and not in surface of the floor. This is the code:


Game object in game:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class InstantiateCube : MonoBehaviour
6. {
7.  
8.  
9.  
10.  
11.     public GameObject cube;
12.     // Start is called before the first frame update
13.  
14.  
15.  
16.    public void Spawn(Vector3 position){
17.  
18.  
19. Instantiate(cube).transform.position = position;
20.  
21.  
22.    }
23.  
24.     // Update is called once per frame
25.     void Update()
26.     {
27.      
28. if(Input.GetKeyDown(KeyCode.Mouse0)){
29.  
30. Vector3 worldPoint = Camera.main.ScreenToWorldPoint(Input.mousePosition,Camera.MonoOrStereoscopicEye.Mono);
31.  
32. Vector3 adjustZ = new Vector3(worldPoint.x,worldPoint.y,cube.transform.position.z);
33.  
34. Spawn(adjustZ);
35.  
36.  
37.  
38. }
39.  
40.  
41.  
42.  
43.  
44.  
45.     }
46. }

 

Use Physics.Raycast to cast ray from camera through mouse pointer. When ray hits the ground, create the object on that position.

 

Ok that worked,thanks. I have another problem. When I instantiate a new object some objects overlap others. How I fix that?

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class testclick : MonoBehaviour
6. {
7.     // Start is called before the first frame update
8.    public GameObject cube;
9.     // Start is called before the first frame update
10.   Ray myRay;
11.  
12. RaycastHit hit;
13.  
14.  
15.  
16.     // Update is called once per frame
17.     void Update()
18.     {
19.        
20. myRay = Camera.main.ScreenPointToRay(Input.mousePosition);
21.  
22. if(Physics.Raycast(myRay,out hit)){
23.  
24. if(Input.GetMouseButtonDown(0)){
25.  
26. Instantiate (cube,hit.point,Quaternion.identity);
27.  
28.  
29.  
30.  
31. }
32.  
33.  
34.  
35.  
36. }
37.  
38.  
39.     }
40. }

 

That depends on your game logic. In general, you may check if colliders overlap or use OnTriggerEnter to disable placement if there are obstacles for instance.