MouseRaycastExample.cs

public class MouseRaycastExample : MonoBehaviour {
  public void MouseRaycast () {
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        RaycastHit hit;

        if (Input.GetMouseButtonDown(0) &&
            Physics.Raycast(ray, out hit)) {
            GameObject created = Instantiate(chispas);
            created.transform.position = hit.point;
        }
    }
}