JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://rawgithub.com/BabylonJS/Babylon.js/master/babylon.1.11.js"></script>
<canvas id="renderCanvas"></canvas>

CSS

html, body, div, canvas {
    width: 100%;
    height: 100%;
    padding: 0;
    margin: 0;
    overflow: hidden;
}

JavaScript

BABYLON.Mesh.prototype._setVerticesDataByMerging = function (meshesToMerge, kind, doNotDeleteAfterMerging) {
    if (!(meshesToMerge instanceof Array))
        meshesToMerge = [meshesToMerge];
    
    var vertices = [];
    var indices = [];
    
    // Indices are only useful for positions.
    if (kind === BABYLON.VertexBuffer.PositionKind)
        indices = this.getIndices();
    
    // Calculate center of all meshes merged to know the final center, 
    // thus we'll transform all vertices position into the new center space.
    var center = this.position;
    // Use to know how many times the current mesh (this) appear in meshToMerge.
    var currentMeshApparition = 0;
    
    for (var i in meshesToMerge) {
        var meshToMerge = meshesToMerge[i];
        
        if (meshToMerge === this && meshToMerge.id === this.id) {
            ++currentMeshApparition;
            // Trying to merge with itself.
            continue;
        }
        
        center = center.add(meshToMerge.getAbsolutePosition());
    }
    
    // We substract the number of apparition because we do not need to merge the mesh with itself.
    // +1 because "this" is not in meshesToMerge array.
    var meshesCount = meshesToMerge.length - currentMeshApparition + 1;
    
    if (meshesCount > 0)
        center = center.scale(1 / meshesCount);
    
    // transformMatrixCenter to convert all vertices of each mershToMerge in center space.
    var transformMatrixCenter = BABYLON.Matrix.Translation(center.x, center.y, center.z);
    transformMatrixCenter.invert();
    
    var meshParent = this.parent;
    var parentWorldMatrixInv;
    
    if (meshParent) {
        parentWorldMatrixInv = meshParent.getWorldMatrix().clone();
        parentWorldMatrixInv.invert();
    }
    
    var meshTransformMatrix;
    if (kind === BABYLON.VertexBuffer.PositionKind
        || kind === BABYLON.VertexBuffer.NormalKind) {
        meshTransformMatrix = this._localWorld.multiply(transformMatrixCenter);
...