text: 2014 SOLIDWORKS Help - General Import Options
  Merge Entities (for Inventor Part, SAT, STEP, or IGES)
  Import multiple bodies as parts (IGES, STEP, UG, and ACIS only). Imports a multibody part as separate part documents in an assembly document. When cleared, the multibody part imports as a part document with multiple bodies.
  Perform full entity check and repair errors Checks and repairs errors. Import performance is slower because the software spends time checking and (when possible) repairing the model entities.
  Automatically run Import Diagnostics (Healing) When importing a file, Import Diagnostics runs automatically. When cleared, a prompt appears for each import action asking if you want to run Import Diagnostics.
  Customize curve tolerance Customizes the tolerance when importing models with very small entities (smallest values on the order of 1.0e-6 to 1.0e-7 meters). When cleared, SolidWorks uses internal tolerance settings, which are too large to properly import and display these small models. Enter a tolerance in the box.