When loading structured parts (normally by right-clicking a part in the Parts list that has not yet been loaded), there is some flexibility in what is actually extracted. If the model contains iblanking, then you have control over which iblanking domain to use, namely Inside, Outside (blanked out), or All (which ignores the iblanking). If no iblanking in the model, the domain is All by default. You can do things like extracting all or portions of zones at original or coarser resolutions or doing the extractions on single or multiple zones.