function addNode(node, parent_geomentry) {
    var tmp_geometry = new THREE.BoxGeometry( 20, 20, 20);
    var mesh = new THREE.Mesh(tmp_geometry);
    mesh.position.x = node.coords.x;
    mesh.position.y = node.coords.y;
    mesh.position.z = node.coords.z;

    mesh.updateMatrix();
    parent_geomentry.merge(mesh.geometry, mesh.matrix);
    node_meshes.push(mesh);
}