I am working with an extremely large assembly file that we imported from a STEP file supplied by our customer.  This file has an extremely large number of part models generated of surface data.  I am trying to break it up into managable sub-assemblies.  To do so I need to delete large selections of components.  When I do so it is taking hours to process the select and delete commands.  Does anyone know of a faster way to achive this goal than an on screen select and delete?

SW 2014 SP 3.0