유니티3d mesh의 normal, face direction 관련된 내용

출처: https://forum.unity.com/threads/get-simple-rectangle-shaped-mesh-face-direction.264826/

정답 답변

IsGreen

Joined:

Jan 17, 2014

Posts:

206

Mesh vertices use local positions, need to convert it to world position to calculate center rectangle.

I used a Quad as rectangle in this example. Spawned object must look at to forward axis.

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. [RequireComponent(typeof(MeshFilter))]
5. public class temp : MonoBehaviour {
6.  
7.     public GameObject prefab;
8.  
9.     GameObject instancePrefab;
10.     Mesh meshQuad;
11.  
12.     void Start(){
13.  
14.         meshQuad = GetComponent<MeshFilter>().mesh;
15.         instancePrefab = (GameObject)Instantiate(prefab);
16.  
17.     }
18.  
19.     void prefabLookAt(){
20.  
21.         Matrix4x4 localToWorld = transform.localToWorldMatrix;
22.  
23.         Vector3 v0 = localToWorld.MultiplyPoint3x4(meshQuad.vertices[meshQuad.triangles[0]]);
24.         Vector3 v1 = localToWorld.MultiplyPoint3x4(meshQuad.vertices[meshQuad.triangles[1]]);
25.         Vector3 v2 = localToWorld.MultiplyPoint3x4(meshQuad.vertices[meshQuad.triangles[2]]);
26.  
27.         Vector3 normal = Vector3.Cross(v1-v0,v2-v0);
28.      
29.         Vector3 center = Vector3.zero;
30.      
31.         int i;
32.         for(i=0;i<meshQuad.vertices.Length;i++)
33.             center += localToWorld.MultiplyPoint3x4(meshQuad.vertices[i]);
34.      
35.         center /= (float)i;
36.  
37.         instancePrefab.transform.position = center;
38.         instancePrefab.transform.rotation = Quaternion.LookRotation(normal);
39.  
40.     }
41.  
42.     void Update(){
43.  
44.         prefabLookAt();
45.  
46.     }
47.  
48. }