How do I place the matching Vector3 array values of a Vector3 array in a new array ?

Question

hello , I am attempting to place the values of an array that are the same; inside of a separate.

this is a code i adopted and tried to use to move an objects verts , however; this script assigned points called "handles" to each vert as a child of the object . As a result , moving the handles results in simply pulling the mesh apart by individual verts.

I tried to group all the verts with the same Vector3 positions into an array and setting all the vector3 values of that array to be equal to the position of the handle.

 using UnityEngine;
 using System.Collections;
 
 [ExecuteInEditMode]
 
 public class VertHandler : MonoBehaviour
 {
     Mesh mesh;
     Vector3[] verts;
     Vector3 vertPos;
     GameObject[] handles;
     void OnEnable()
     {
         mesh = GetComponent<MeshFilter>().mesh;
         verts = mesh.vertices;
         foreach (Vector3 vert in verts)
         {
             vertPos = transform.TransformPoint(vert);
             GameObject handle = new GameObject("handle");
             handle.transform.position = vertPos;
             handle.transform.parent = transform;
             handle.tag = "handle";
             //handle.AddComponent<Gizmo_Sphere>();
         }
     }
 
     void OnDisable()
     {
         GameObject[] handles = GameObject.FindGameObjectsWithTag("handle");
         foreach (GameObject handle in handles)
         {
             DestroyImmediate(handle);
         }
     }
 
     void Update()
     {
         handles = GameObject.FindGameObjectsWithTag("handle");
         for (int i = 0; i < verts.Length; i++)
         {
             verts[i] = handles[i].transform.localPosition;
         }
         mesh.vertices = verts;
         mesh.RecalculateBounds();
         mesh.RecalculateNormals();
     }
 }

Answer 1

Best Answer

Answer by Bunny83 · Nov 11, 2014 at 06:05 PM

Ok, for mesh manipulations you actually want to store the indices of similar vertices so you can update them all at once. just copying the vector3 value won't help much since you don't know where it belongs in the actual vertices array.

I would suggest to use a helper class like:

 public class VertHandle
 {
     public Vector3 pos;
     public List<int> indices = new List<int>();
     public Transform handle;
 }

With that class you can create a unique handle for each vertex-group like this:

 List<VertHandle> GenerateHandles(Vector3[] aVertices, float aThreshold)
 {
     float sqrThreshold = aThreshold*aThreshold;
     List<VertHandle> result = new List<VertHandle>();
     for(int i = 0; i < aVertices.Length; i++)
     {
         VertHandle h = null;
         for(int n = 0; n < result.Count; n++)
         {
             if ((result[n].pos - aVertices[i]).sqrMagnitude < sqrThreshold)
             {
                 h = result[n];
                 break;
             }
         }
         // if there's no handle with that position yet, create one.
         if(h == null)
         {
             h = new VertHandle() { pos = aVertices[i]};
             h.handle = new GameObject("handle").transform;
             h.handle.parent = transform;
             h.handle.localPosition = aVertices[i];
             h.handle.tag = "handle";
             result.Add(h);
         }
         // add the current vertex to the indices list of that handle
         h.indices.Add(i);
     }
     return result;
 }

This gives you a list of handles. To apply the changes from the handles to your actual vertices, just use

 void ApplyChanges(List<VertHandle> aHandles, Vector3[] aVertices)
 {
     for(int i = 0; i < aHandles.Count; i++)
     {
         Vector3 pos = aHandles[i].handle.localPosition;
         for(int n = 0; n < aHandles[i].indices.Count; n++)
         {
             aVertices[aHandles[i].indices[n]] = pos;
         }
     }
 }

Keep in mind when destroying the handles to use

 foreach (VertHandle h in handles)
 {
     DestroyImmediate(h.handle.gameObject);
 }

Also make sure you store the handles List in your class in a member variable.

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Bunny83 · Nov 11, 2014 at 06:40 PM 0

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Sorry, I forgot to add the VertHandle instance to the result list. Added the it in line 24!

It works for me. If i "edit" the default cube i get 8 handles. However you should use ".shared$$anonymous$$esh" ins$$anonymous$$d of ".mesh" as .mesh will cause a memory leak as it duplicates the mesh. It's ment to be used at runtime only.

edit
You might want to create a copy of the mesh before starting editing it:

 mesh = ($$anonymous$$esh)Instantiate(mf.shared$$anonymous$$esh); // create copy
 mesh.name = mf.shared$$anonymous$$esh.name;  // keep the old name (removes the "(clone)")
 mf.shared$$anonymous$$esh = mesh; // use this mesh from now on

This might cause the mesh to "leak" as well since if the old mesh isn't used anymore by another object it's orphaned. When you save the scene Unity will notice you that the mesh has leaked. Unfortunately there's no clean way to detect that case.

Also I should mention that the mesh you're editing will be saved in the scene itself. Usually it's better to store it as asset in the project. But again that should be done from an editor script and not a runtime script with ExecuteInEdit$$anonymous$$ode.

DaiMangouDev · Nov 11, 2014 at 08:59 PM 0

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hey,i'm having trouble putting this together correctly . I dont understand the definition of ApplyChanges. how did you put this code together ? sorry i'm not used to this method of coding using lists. oh , and and thank you for the answer.

Bunny83 · Nov 11, 2014 at 10:00 PM 1

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@ruchmair:

I've put my test script on my dropbox

DaiMangouDev · Nov 12, 2014 at 12:47 AM 0

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Great, worked really well. I don't think i could have written it by myself . thanks again. I' going to edit it so that I can "select the verts" themselves and move them as I would in 3D modeling software , then I will share the code .

There is also the issue of mesh deformation when the script is place on an object . I'm going to work on making the verts "visible" and selectable first.

How do I place the matching Vector3 array values of a Vector3 array in a new array ?

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