How to detect if player is near to a GameObject(C#)Unity5

Question

How can i possibly detect if the player is near at the object . Without the help of raycast.

Here is my code:

[SerializedField]
Transform obj1;

public GameObject player;

void Update(){
    if(obj1.transform.position - player.position < 5) {
       audio.Play();
    }
}

This is what i like to obtain . How can i do it like that. Help please

Answer 1

obj1.transform.position - player.position will return a Vector3 . You can use the magnitude of that vector as your distance:

if ((obj1.transform.position - player.position).magnitude < 5.0f)
    audio.Play();

As a bit of a performance tip, you can save an expensive square-root operation by instead using the magnitude squared:

if ((obj1.transform.position - player.position).sqrMagnitude < 25.0f)
    audio.Play();

Answer 2

You can find whether an object is near another object with the following code:

float distance = Vector3.Distance(object1.transform.position, object2.transform.position);
float maxDistance = 10.0f;
bool isNear = distance <= maxDistance;