JSONArray structures = entry.getJSONArray("structures");
for (int i=0 ; i < structures.length() ; i++) {
String id = structures.getJSONObject(i).getString("model_identifier");
JSONArray structures = entry.getJSONArray("structures");
for (int i=0 ; i < structures.length() ; i++) {
String id = structures.getJSONObject(i).getString("model_identifier");