What exactly is a "soft" breakline?
Due to a number of issues, my terrain editing has primarily been in Ss2 and earlier. We can't get all of what we need out of Open Roads Survey and our clients are still in Ss2, so I have avoided much in depth Open Roads Survey work.
I assumed the reformulation of triangle has to do with the triangulation algorithm. When a new breakline is added, the algorithm looks for its "smallest possible triangle between three points" and finds a different group of points now that certain previously eliminated triangle are now acceptable due to how the added breaklines cause them to form.