Why does my object disappear?

transform.localScale = new Vector3(size,siee,siee);

I put that line in funtion Update() and after a few changes (objects is getting smaller while going out) object just disappear (dont know why). Pls help me :(

rest of the code:

using UnityEngine;
using System.Collections;

public class scaleIt : MonoBehaviour {

    private float farSize = 1.0f;
    private float closeSize = 2.0f; 
    private float possition; //20-320 na Y
    private float piece;
    private float sizee;

    void Update () {

        possition = Mathf.Round(otherscript.possition);
        piece = (close - far)/300; //300px Y size
        sizee = close - (piece * possition);
        // print(close - sizee);
        transform.localScale = new Vector3(sizee,sizee,sizee);


Well, Update() happens every frame, in one second, you can have 30-200 frames, so, you're scaling the object down VERY fast, until it is nothing...

Put a var times = 0, and only let it happen once, by times++ and in the if statement when you need it to do that, have it if times == 0 than do ___.