# Copy BufferGeometry/Mesh in place

**URL:** <https://discourse.threejs.org/t/copy-buffergeometry-mesh-in-place/21966>\
**Category:** Questions\
**Tags:** object3d\
**Created:** [December 27, 2020, 11:42pm UTC](https://discourse.threejs.org/t/copy-buffergeometry-mesh-in-place/21966 "2020-12-27T23:42:45Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![fleixi](https://avatars.discourse-cdn.com/v4/letter/f/3da27b/32.png) [@fleixi](https://discourse.threejs.org/u/fleixi)\
**Post date:** [December 27, 2020, 11:42pm UTC](https://discourse.threejs.org/t/copy-buffergeometry-mesh-in-place/21966/1 "2020-12-27T23:42:46Z")

</div>

I like to copy a 3dObject in place but all matrixs are getting reset and the copied object is somewhere else in the scene. What do i wrong?

Originalobject:

```
1. oa {uuid: "900269EB-3D05-4A79-87FC-7596EEC94918", name: "", type: "Mesh", parent: Mr, children: Array(0), …}

  1. castShadow: true
  2. children: []
  3. frustumCulled: true
  4. geometry: ki {uuid: "E495D41C-F204-4D41-A53F-32AFC59FEE0C", name: "", type: "BufferGeometry", index: Li, attributes: {…}, …}
  5. layers: lr {mask: 1}
  6. material: il {uuid: "504CB1D7-717E-42E4-AE85-7584E355F292", name: "gem", type: "MeshPhysicalMaterial", fog: true, blending: 1, …}
  7. matrix: ar

    1. elements: (16) [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]
    2. __proto__ : Object

  8. matrixAutoUpdate: true
  9. matrixWorld: ar

    1. elements: (16) [1, 0, 0, 0, 0, 2.220446049250313e-16, -1, 0, 0, 1, 2.220446049250313e-16, 0, -12.898780822753906, 10.827563285827638, -0.07714200019836186, 1]
    2. __proto__ : Object

  10. matrixWorldNeedsUpdate: false
  11. name: ""
  12. parent: Mr {uuid: "CF28A87B-ADA3-4C46-B52D-46865554F6EB", name: "", type: "Object3D", parent: Ao, children: Array(1), …}
  13. position: Qn {x: 0, y: 0, z: 0}
  14. quaternion: Yn {_x: 0, _y: 0, _z: 0, _w: 1, _onChangeCallback: ƒ}
  15. receiveShadow: false
  16. renderOrder: 0
  17. rotation: cr {_x: 0, _y: 0, _z: 0, _order: "XYZ", _onChangeCallback: ƒ}
  18. scale: Qn {x: 1, y: 1, z: 1}
  19. type: "Mesh"
  20. up: Qn {x: 0, y: 1, z: 0}
  21. userData: {}
  22. uuid: "900269EB-3D05-4A79-87FC-7596EEC94918"
  23. visible: true
  24. drawMode: (...)
  25. eulerOrder: (...)
  26. id: 7
  27. modelViewMatrix: ar

    1. elements: (16) [0.7071067811865477, 0.3545308169249882, -0.6118070773131842, 0, -0.7071067811865475, 0.3545308169249884, -0.6118070773131842, 0, 1.570092458683775e-16, 0.8652258662921498, 0.5013822895745312, 0, -9.175363020262832, -4.547232208794878, -481.92182505610884, 1]
    2. __proto__ : Object

  28. normalMatrix: Gn

    1. elements: (9) [0.7071067811865474, 0.35453081692498795, -0.6118070773131841, -0.7071067811865474, 0.3545308169249883, -0.611807077313184, 1.110223024625156e-16, 0.8652258662921495, 0.5013822895745311]
    2. __proto__ : Object

  29. useQuaternion: (...)
  30. __proto__ : Mr

```

Copied Object:

```
1. oa {uuid: "7E7757B9-3B1B-46FD-88D6-4720F13B7125", name: "", type: "Mesh", parent: null, children: Array(0), …}

  1. castShadow: true
  2. children: []
  3. frustumCulled: true
  4. geometry: ki {uuid: "E495D41C-F204-4D41-A53F-32AFC59FEE0C", name: "", type: "BufferGeometry", index: Li, attributes: {…}, …}
  5. layers: lr {mask: 1}
  6. material: Rr {uuid: "74992A47-B0AA-4218-8575-37DC3C62E0DA", name: "", type: "MeshBasicMaterial", fog: true, blending: 1, …}
  7. matrix: ar {elements: Array(16)}
  8. matrixAutoUpdate: true
  9. matrixWorld: ar {elements: Array(16)}
  10. matrixWorldNeedsUpdate: false
  11. name: ""
  12. parent: On

    1. autoUpdate: true
    2. background: wr {r: 1, g: 1, b: 1}
    3. castShadow: false
    4. children: (4) [vh, Ao, Mr, oa]
    5. environment: Yi {uuid: "6CC4BA54-AE89-40D9-9FE8-119DC6E528A7", name: "", image: Array(6), mipmaps: Array(0), mapping: 301, …}
    6. fog: null
    7. frustumCulled: true
    8. layers: vn {mask: 1}
    9. matrix: dn

      1. elements: (16) [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]
      2. __proto__ : Object

    10. matrixAutoUpdate: true
    11. matrixWorld: dn

      1. elements: (16) [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]
      2. __proto__ : Object

    12. matrixWorldNeedsUpdate: false
    13. name: ""
    14. overrideMaterial: null
    15. parent: null
    16. position: an {x: 0, y: 0, z: 0}
    17. quaternion: tn {_x: 0, _y: 0, _z: 0, _w: 1, _onChangeCallback: ƒ}
    18. receiveShadow: false
    19. renderOrder: 0
    20. rotation: gn {_x: 0, _y: 0, _z: 0, _order: "XYZ", _onChangeCallback: ƒ}
    21. scale: an {x: 1, y: 1, z: 1}
    22. type: "Scene"
    23. up: an {x: 0, y: 1, z: 0}
    24. userData: {}
    25. uuid: "9CFDFDF4-01A6-4653-ACBB-9231190581EF"
    26. visible: true
    27. _listeners: {dispose: Array(2)}
    28. eulerOrder: (...)
    29. id: 6
    30. modelViewMatrix: dn

      1. elements: (16) [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]
      2. __proto__ : Object

    31. normalMatrix: Yt

      1. elements: (9) [1, 0, 0, 0, 1, 0, 0, 0, 1]
      2. __proto__ : Object

    32. useQuaternion: (...)
    33. __proto__ : Cn

  13. position: Qn {x: 0, y: 0, z: 0}
  14. quaternion: Yn {_x: 0, _y: 0, _z: 0, _w: 1, _onChangeCallback: ƒ}
  15. receiveShadow: false
  16. renderOrder: 0
  17. rotation: cr {_x: -0, _y: 0, _z: -0, _order: "XYZ", _onChangeCallback: ƒ}
  18. scale: Qn {x: 1.05, y: 1.05, z: 1.05}
  19. type: "Mesh"
  20. up: Qn {x: 0, y: 1, z: 0}
  21. userData: {}
  22. uuid: "7E7757B9-3B1B-46FD-88D6-4720F13B7125"
  23. visible: true
  24. drawMode: (...)
  25. eulerOrder: (...)
  26. id: 28
  27. modelViewMatrix: ar {elements: Array(16)}
  28. normalMatrix: Gn {elements: Array(9)}
  29. useQuaternion: (...)
  30. __proto__ : Mr

```

Code:

```
let nMesh = oldMesh.clone();
nMesh.material = outlineMaterial;
nMesh.material.needsUpdate = true;
nMesh.matrix.set(oldMesh.matrix);
nMesh.matrixWorld.set(oldMesh.matrixWorld);
nMesh.matrixWorldNeedsUpdate = true;
```

---

<div class="post-metadata">

**Author:** ![gkjohnson](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/gkjohnson/32/2298_2.png) [@gkjohnson](https://discourse.threejs.org/u/gkjohnson)\
**Post date:** [December 27, 2020, 11:49pm UTC](https://discourse.threejs.org/t/copy-buffergeometry-mesh-in-place/21966/2 "2020-12-27T23:49:49Z")

</div>

If you’d like to clone an object and add it to a different parent while having it retain the same position in the world look into using the [Object3D.attach](https://threejs.org/docs/#api/en/core/Object3D.attach) function.

---

<div class="post-metadata">

**Author:** ![Mugen87](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/mugen87/32/5645_2.png) [@Mugen87](https://discourse.threejs.org/u/Mugen87)\
**Post date:** [December 28, 2020, 11:42am UTC](https://discourse.threejs.org/t/copy-buffergeometry-mesh-in-place/21966/3 "2020-12-28T11:42:58Z")

</div>

> [@fleixi](#):
>
> `nMesh.matrix.set(oldMesh.matrix);`

`set()` does expected a series of numbers representing the matrix elements. You can’t use a matrix as an argument.

---

<div class="post-metadata">

**Author:** ![fleixi](https://avatars.discourse-cdn.com/v4/letter/f/3da27b/32.png) [@fleixi](https://discourse.threejs.org/u/fleixi)\
**Post date:** [December 28, 2020, 12:00pm UTC](https://discourse.threejs.org/t/copy-buffergeometry-mesh-in-place/21966/4 "2020-12-28T12:00:35Z")

</div>

Thanks for helping but i really don’t get the basic. If i copy a object and attach it to the same parent i expect that the object is on the same place. Therefor i have stripped down the code to this:

```
let oldMesh = group.children[0].children[0];
console.log(oldMesh);
let nMesh = oldMesh.clone();
nMesh.material = outlineMaterial;
nMesh.material.needsUpdate = true;
group.children[0].attach(nMesh);
console.log(nMesh);

```

but the new mesh is on a complete different place.

Old Mesh:

```
1. oa

  1. castShadow: true
  2. children: []
  3. frustumCulled: true
  4. geometry: ki {uuid: "FAB188C3-A648-43AA-935B-76A0DA0F95E7", name: "", type: "BufferGeometry", index: Li, attributes: {…}, …}
  5. layers: lr {mask: 1}
  6. material: il {uuid: "E2977014-C8B0-408B-9683-1C54C0E75D3F", name: "gem", type: "MeshPhysicalMaterial", fog: true, blending: 1, …}
  7. matrix: ar {elements: Array(16)}
  8. matrixAutoUpdate: true
  9. matrixWorld: ar {elements: Array(16)}
  10. matrixWorldNeedsUpdate: false
  11. name: ""
  12. parent: Mr {uuid: "FB1D8BF2-27BD-4B3B-9B23-A40447555E9B", name: "", type: "Object3D", parent: Ao, children: Array(2), …}
  13. position: Qn {x: 0, y: 0, z: 0}
  14. quaternion: Yn {_x: 0, _y: 0, _z: 0, _w: 1, _onChangeCallback: ƒ}
  15. receiveShadow: false
  16. renderOrder: 0
  17. rotation: cr {_x: 0, _y: 0, _z: 0, _order: "XYZ", _onChangeCallback: ƒ}
  18. scale: Qn {x: 1, y: 1, z: 1}
  19. type: "Mesh"
  20. up: Qn {x: 0, y: 1, z: 0}
  21. userData: {}
  22. uuid: "BF792C98-D776-4614-A468-8DFE88CA36AE"
  23. visible: true
  24. drawMode: (...)
  25. eulerOrder: (...)
  26. id: 7
  27. modelViewMatrix: ar {elements: Array(16)}
  28. normalMatrix: Gn {elements: Array(9)}
  29. useQuaternion: (...)
  30. __proto__ : Mr

```

new Mesh:

```
1. oa

  1. castShadow: true
  2. children: []
  3. frustumCulled: true
  4. geometry: ki {uuid: "FAB188C3-A648-43AA-935B-76A0DA0F95E7", name: "", type: "BufferGeometry", index: Li, attributes: {…}, …}
  5. layers: lr {mask: 1}
  6. material: Rr {uuid: "052BA9F5-951D-48C9-B1E7-81C555A65E26", name: "", type: "MeshBasicMaterial", fog: true, blending: 1, …}
  7. matrix: ar {elements: Array(16)}
  8. matrixAutoUpdate: true
  9. matrixWorld: ar {elements: Array(16)}
  10. matrixWorldNeedsUpdate: false
  11. name: ""
  12. parent: Mr {uuid: "FB1D8BF2-27BD-4B3B-9B23-A40447555E9B", name: "", type: "Object3D", parent: Ao, children: Array(2), …}
  13. position: Qn {x: 12.898780822753906, y: -0.07714200019836426, z: -10.827563285827638}
  14. quaternion: Yn {_x: 0.7071067811865475, _y: 0, _z: 0, _w: 0.7071067811865476, _onChangeCallback: ƒ}
  15. receiveShadow: false
  16. renderOrder: 0
  17. rotation: cr {_x: 1.5707963267948963, _y: 0, _z: -0, _order: "XYZ", _onChangeCallback: ƒ}
  18. scale: Qn {x: 1, y: 1, z: 1}
  19. type: "Mesh"
  20. up: Qn {x: 0, y: 1, z: 0}
  21. userData: {}
  22. uuid: "B7611B38-FA9C-4F63-A00D-7DEBC3075869"
  23. visible: true
  24. drawMode: (...)
  25. eulerOrder: (...)
  26. id: 28
  27. modelViewMatrix: ar {elements: Array(16)}
  28. normalMatrix: Gn {elements: Array(9)}
  29. useQuaternion: (...)
  30. __proto__ : Mr

```

What do i need to do to get a copy on the same place?

---

<div class="post-metadata">

**Author:** ![gkjohnson](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.threejs.org/gkjohnson/32/2298_2.png) [@gkjohnson](https://discourse.threejs.org/u/gkjohnson)\
**Post date:** [December 29, 2020, 1:20am UTC](https://discourse.threejs.org/t/copy-buffergeometry-mesh-in-place/21966/5 "2020-12-29T01:20:22Z")

</div>

There are two ways to add children in three.js: [Object3D.attach](https://threejs.org/docs/#api/en/core/Object3D.attach) and [Object3D.add](https://threejs.org/docs/#api/en/core/Object3D.add). `attach` modifies the `position` and `rotation` of the child object such that it will retain its position in world space relative to it’s current world space while `add` uses them as the transformation relative to the parent. Keep in mind that when you clone an object it does not have a parent and it copies the position and rotation from the original object. It sounds like you want `add` in this case.

---

<div class="post-metadata">

**Author:** ![fleixi](https://avatars.discourse-cdn.com/v4/letter/f/3da27b/32.png) [@fleixi](https://discourse.threejs.org/u/fleixi)\
**Post date:** [December 30, 2020, 6:09pm UTC](https://discourse.threejs.org/t/copy-buffergeometry-mesh-in-place/21966/6 "2020-12-30T18:09:32Z")

</div>

thanks now i understand a little bit more. Working now