javascript - How to merge two BufferGeometries in one BufferGeometry in Three.JS? - Stack Overflow

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How to merge two buffer geometries in one THREE.BufferGeometry in ThreeJS ?

var modelGeometry = null;

geometry = new THREE.CylinderGeometry( 10, 10, 10 );

if (modelGeometry == null)
{
    modelGeometry = new THREE.BufferGeometry().fromGeometry(geometry);
    console.log(modelGeometry);
}

bufGeometry = new THREE.SphereBufferGeometry( 20 , 20, 20 );

var mesh = new THREE.Mesh( bufGeometry, material );

modelGeometry.merge(mesh.geometry, mesh.matrix);

Doesn't do anything with modelGeometry. How merge these geometries correct?

How to merge two buffer geometries in one THREE.BufferGeometry in ThreeJS ?

var modelGeometry = null;

geometry = new THREE.CylinderGeometry( 10, 10, 10 );

if (modelGeometry == null)
{
    modelGeometry = new THREE.BufferGeometry().fromGeometry(geometry);
    console.log(modelGeometry);
}

bufGeometry = new THREE.SphereBufferGeometry( 20 , 20, 20 );

var mesh = new THREE.Mesh( bufGeometry, material );

modelGeometry.merge(mesh.geometry, mesh.matrix);

Doesn't do anything with modelGeometry. How merge these geometries correct?

• javascript
• merge
• three.js
• buffer-geometry

Share Improve this question Follow edited Jul 13, 2016 at 16:04 Wilt 44.5k1515 gold badges160160 silver badges214214 bronze badges asked Apr 6, 2016 at 12:04 EvgyEvgy 39611 gold badge33 silver badges1010 bronze badges 6

• I do not think merging of buffer geometry works correctly. Try merging regular geometries: THREE.CylinderGeometry and THREE.SphereGeometry. – WestLangley Commented Apr 6, 2016 at 14:08
• It looks like there is a bug in merge functiun of BufferGeometry. – Evgy Commented Apr 6, 2016 at 17:06
• 1 BufferGeometry.merge() does not currently support indexed-BufferGeometry, which is what you are using in your example. (three.js r.75) – WestLangley Commented Apr 6, 2016 at 17:20
• There is way to draw those primitives without indexed-BufferGeometry? – Evgy Commented Apr 6, 2016 at 17:43
• BufferGeometry.toNonIndexed(). But I restate my first ment. – WestLangley Commented Apr 6, 2016 at 17:51

 |  Show 1 more ment

2 Answers 2

Sorted by: Reset to default 3

Strangely calling merge() on a BufferGeometry gave me some errors, but there's a workaround:

1. Merge two Geometry objects;
2. Convert to BufferGeometry;
3. Add to a Mesh

Here's what's working for me:

    var modelGeometry = new THREE.Geometry();

    cylGeometry = new THREE.CylinderGeometry( 10, 10, 10 );

    // if (modelGeometry == null)
    // {
    //     modelGeometry = new THREE.BufferGeometry().fromGeometry(geometry);
    //     console.log(modelGeometry);
    // }

    modelGeometry.merge(cylGeometry);

    sphereGeometry = new THREE.SphereGeometry( 20 , 20, 20 );

    modelGeometry.merge(sphereGeometry);

    bufGeometry = new THREE.BufferGeometry().fromGeometry(modelGeometry);

    var mesh = new THREE.Mesh( bufGeometry, material );

    scene.add(mesh);

I'll dance all night long. Did it!

sumPosArr = new Float32Array(poslen);
sumNormArr = new Float32Array(normlen);
sumUvArr = new Float32Array(uvlen);

var postotalarr = new Array();

sumPosCursor = 0;
sumNormCursor = 0;
sumUvCursor = 0;

for (a = 0; a < objects.length; a++ )
{
    var posAttArr = objects[a].geometry.getAttribute('position').array;

    for (b = 0; b < posAttArr.length; b++)
    {
        sumPosArr[b + sumPosCursor] = posAttArr[b];
    }

    sumPosCursor += posAttArr.length;


    var numAttArr = objects[a].geometry.getAttribute('normal').array;

    for (b = 0; b < numAttArr.length; b++)
    {
        sumNormArr[b + sumNormCursor] = numAttArr[b];
    }

    sumNormCursor += numAttArr.length;


    var uvAttArr = objects[a].geometry.getAttribute('uv').array;

    for (b = 0; b < uvAttArr.length; b++)
    {
        sumUvArr[b + sumUvCursor] = uvAttArr[b];
    }

    sumUvCursor += uvAttArr.length;

}

modelGeometry.addAttribute('position', new THREE.BufferAttribute(sumPosArr, 3 ));
modelGeometry.addAttribute('normal', new THREE.BufferAttribute(sumNormArr, 3 ));
modelGeometry.addAttribute('uv', new THREE.BufferAttribute(sumUvArr, 2 ));

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