Hello from Spain.
Its known that AutoCAD is a very powerful tool for dimensioning.
But Revit is not as flexible as AutoCAD. It is difficult to place a dimension among two entitities that are not parallel. You have to press "tab" several times in order to get the proper point on the second object, and in many cases this is not possible.
It would be nice if revit could detect nearest point, ortho point or else other in order to place the second point of a dimensión without drawing any auxiliar line or plane.
Regards.