The snap options in Solidworks are really of very little use to most users. For example they do not work when dimensioning features.  They also do not work when measuring features in fact the only place where I have seen them work is for adjusting existing dimensions.  Most of the rest of the time all the command icons are greyed out.  The snap options are for the most part totally useless.  If Solidworks hopes to compete with AutoCAD, perhaps it should do what AutoCAD can do.... even Draftsight can do this, but not Solidworks.  The dimensioning capabilities of Solidworks really needs to be revamped and upgraded to modern day.  The user should be able to accurately measure from any point to any point in a model or drawing and likewise put a dimension in the same place, if only for reference, but this is not possible.