// get 3d annotation links
List links = DOMUtil.getChildElementsByTagName(el, "link");
if (links.size() > 0) {
PDF3DStream stream = annot.getStreamSafely();
FO3DPDFRenderer renderer = (FO3DPDFRenderer) context.getRenderer();
PDFObject resource = renderer.add3DResourceStream(getClass()
.getResource(ANNOT_MODEL_FILE).toExternalForm());
stream.addResource(ANNOT_RESOURCE_NAME, resource);
// load JavaScript library code once (per 3D stream)
// this is because the DOM element could exist multiple times within