Sometimes, Boolean operations result in VERY tiny edges which SketchUp does not like. In fact, SketchUp will try to clean these edges up whenever you save your model. The problem is that when SketchUp ‘cleans’ or deletes these edges, tiny holes get created in your model and it is no longer a solid.
BoolTools 2 can detect when SketchUp wants to ‘fix’ your model and then stop it from messing up your printable solid models. By applying a special scaling technique, BoolTools 2 can prevent SketchUp from creating these holes in your model.