using UnityEngine;
using System.Collections;
using System.IO;
/// <summary>
/// 點選螢幕實現縮放與旋轉，移動
/// </summary>
public class FingerTouch : MonoBehaviour
{


    private Touch oldTouch1;  //上次觸控點1(手指1)  
    private Touch oldTouch2;  //上次觸控點2(手指2)  

    void Update()
    {

            //沒有觸控  
            if
 
 (Input.touchCount <= 0)
            {
                return;
            }

        //單點觸控， 水平上下移動
        if (Input.touchCount ==1&& Input.GetTouch(0).phase == TouchPhase.Moved)
        {
            var deltaposition = Input.GetTouch(0).deltaPosition;
            transform.Translate(-deltaposition.x * 0.1
 
f, 0f, -deltaposition.y * 0.1f);
        }
        //單點觸控， 水平上下旋轉  
        if (1 == Input.touchCount)
            {
                Touch touch = Input.GetTouch(0);
                Vector2 deltaPos = touch.deltaPosition;
                transform.Rotate(Vector3.down * deltaPos.x, Space.World);
                transform.Rotate(Vector3.right * deltaPos.y, Space.World);
            }

            //多點觸控, 放大縮小  
 

            Touch newTouch1 = Input.GetTouch(0);
            Touch newTouch2 = Input.GetTouch(1);

            //第2點剛開始接觸螢幕, 只記錄，不做處理  
            if (newTouch2.phase == TouchPhase.Began)
            {
                oldTouch2 = newTouch2;
                oldTouch1 = newTouch1;
                return;
            }

            //計算老的兩點距離和新的兩點間距離，變大要放大模型，變小要縮放模型  
            float oldDistance = Vector2.Distance(oldTouch1.position, oldTouch2.position);
            float newDistance = Vector2.Distance(newTouch1.position, newTouch2.position);

            //兩個距離之差，為正表示放大手勢， 為負表示縮小手勢  
            float offset = newDistance - oldDistance;

            //放大因子， 一個畫素按 0.01倍來算(100可調整)  
            float scaleFactor = offset / 100f;
            Vector3 localScale = transform.localScale;
            Vector3 scale = new Vector3(localScale.x + scaleFactor,
                                        localScale.y + scaleFactor,
                                        localScale.z + scaleFactor);

            //最小縮放到 0.3 倍  
            if (scale.x > 0.3f && scale.y > 0.3f && scale.z > 0.3f)
            {
                transform.localScale = scale;
            }

            //記住最新的觸控點，下次使用  
            oldTouch1 = newTouch1;
            oldTouch2 = newTouch2;

    }
}

2017.09.18
考慮到在移動端介面上可能有大量的UI ，上述方法在點選到UI的時候照樣會觸發移動旋轉縮放等相關功能，所以多上述方法進行了部分修改以及修改了一個bug。

public class FingerTouch : MonoBehaviour
{
    private float minScale = 0.3f;
    private float maxScale = 3f;

    private Touch oldTouch1;  //上次觸控點1(手指1)  
    private Touch oldTouch2;  //上次觸控點2(手指2)  

    void Update()
    {

        //沒有觸控  
        if (Input.touchCount <= 0)
        {
            return;
        }

        //單點觸控， 水平上下移動
        if (Input.touchCount == 1 && Input.GetTouch(0).phase == TouchPhase.Moved)
        {   
            //EventSystem.current.IsPointerOverGameObject(Input.GetTouch(0).fingerId)為true表示點到了UI
            if (!EventSystem.current.IsPointerOverGameObject(Input.GetTouch(0).fingerId))
            {
                var deltaposition = Input.GetTouch(0).deltaPosition;
                transform.Translate(-deltaposition.x * 0.1f, 0f, -deltaposition.y * 0.1f);
            }
        }
        //單點觸控， 水平上下旋轉  
        if (1 == Input.touchCount)
        {

            if (!EventSystem.current.IsPointerOverGameObject(Input.GetTouch(0).fingerId))
            {
                Touch touch = Input.GetTouch(0);
                Vector2 deltaPos = touch.deltaPosition;
                transform.Rotate(Vector3.down * deltaPos.x, Space.World);
                transform.Rotate(Vector3.right * deltaPos.y, Space.World);
            }
        }

        //多點觸控, 放大縮小  
        Touch newTouch1 = Input.GetTouch(0);
        Touch newTouch2 = newTouch1;
        Debug.Log(Input.touchCount);
        if (Input.touchCount == 2)
        {
            newTouch2 = Input.GetTouch(1);
            //第2點剛開始接觸螢幕, 只記錄，不做處理  
            if (newTouch2.phase == TouchPhase.Began)
            {
                oldTouch2 = newTouch2;
                oldTouch1 = newTouch1;
                return;
            }

            //計算老的兩點距離和新的兩點間距離，變大要放大模型，變小要縮放模型  
            float oldDistance = Vector2.Distance(oldTouch1.position, oldTouch2.position);
            float newDistance = Vector2.Distance(newTouch1.position, newTouch2.position);

            //兩個距離之差，為正表示放大手勢， 為負表示縮小手勢  
            float offset = newDistance - oldDistance;

            //放大因子， 一個畫素按 0.01倍來算(100可調整)  
            float scaleFactor = offset / 100f;
            Vector3 localScale = transform.localScale;
            Vector3 scale = new Vector3(localScale.x + scaleFactor,
                                        localScale.y + scaleFactor,
                                        localScale.z + scaleFactor);
            if (!EventSystem.current.IsPointerOverGameObject(Input.GetTouch(0).fingerId)
                && !EventSystem.current.IsPointerOverGameObject(Input.GetTouch(1).fingerId))
            {
                //最小縮放到 0.3 倍 ，最大放大到 3 倍
                if (scale.x > minScale && scale.y > minScale && scale.z > minScale && scale.x < maxScale && scale.y < maxScale && scale.z < maxScale)
                {
                    transform.localScale = scale;
                }
                //記住最新的觸控點，下次使用  
                oldTouch1 = newTouch1;
                oldTouch2 = newTouch2;
            }
        }
    }
}