Hi Neil, that one seems to be built in a "patch by patch" type method where some profiles were drawn in and several surfaces probably constructed using a sweep or network type tool. One problem though with this kind of patchwork method is it's hard to get a totally smooth result. For example this area has a sharp edge:





It tends to be hard to get really good quality smoothness using this type of approach. But it is overall a pretty difficult thing to model.

Often times something organic where you would need to do a patch-by-patch approach can be handled better by sub-d modeling instead of NURBS modeling for those areas.

- Michael