We introduce a framework for interactive visualization of global flow features in large unsteady 3D flow fields. It is based on selective visualization using dense precomputed integral lines (streamlines, path lines) linked together with all other data attributes. This way we are able to provide an uniform and interactive environment for custom feature specification and visualization of non-local data aspects. These are related to the long term flow behavior, thus their description using only local properties is not possible. We demonstrate the benefits of working with semi-global features by a simple strategy for recognition of recirculation zones within 3D vector fields, judging on a self-proximity measure of integral lines.