public void addNewIndexStream(List <IndexStream.Triangle> l) { IndexStream tri = new IndexStream(l); tri.fixOrientedBox(); indstrm.Add(tri); XmlNode indexstreamparent = shapeNode.SelectSingleNode("PrimitiveSets/PrimitiveSetCtr/Primitives/PrimitiveCtr/IndexStreams"); indexstreamparent.AppendChild(tri.generateNode(xml, Vertices.Count)); }