スクリプトリファレンス

TextMesh.tabSize

public float tabSize;

説明

How much space will be inserted for a tab '\t' character. This is a multiplum of the 'spacebar' character offset.

GetComponent.<TextMesh>().tabSize = 5;

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    void Example() {
        GetComponent<TextMesh>().tabSize = 5;
    }
}