private void ExportCollada_Node(XmlWriter xml, Kn5Node node) {
var boneNames = node.Children.SelectManyRecursive(x => x.Children)
.Where(x => x.NodeClass == Kn5NodeClass.SkinnedMesh)
.SelectMany(x => x.Bones.Select(y => y.Name))
.ToList();
foreach (var t in node.Children) {
ExportCollada_NodeSub(xml, boneNames, t);
}
}