Are Driving Dimensions free?
Yes, since there is a free version of LDD plugin that can be used by anyone to modify parametrically models with driving dimensions. Free version has two limitations: it is not intended for commercial usage and its users cannot add more than 10 driving dimension entities to one SketchUp model. However, any model created with LDD Pro version can be opened and edited parametrically with the free version (even if it contains more than 10 driving dimensions).