It would be VERY beneficial to be able to change the "Boundary Lines" of a "Toposolid" to be a "Hidden Line" without having to use the "Linework" command and go individually click on each boundary line to override it.
The site models with topo lines look cleaner without a border. Not sure why this has never been implemented seeing as though there's an awful lot of people having this need on forums, for some time now.