Demonstrating the powerful but unusual edge and face rounding that DesignSpark (Parasolid) has... REJOICE !
Alternatively, pull two edges a small way, then pull in opposite direction to make a full round.
and for circular rounds, select two edges , pull to create a round on each edge a little, then pull in opposite direction.
To remove the full round, select and Fill.
This also works for eccentric round edge pulls as below gif:
Other tapering helical multi-sided with rotational sections are easily made with DSM if needed.
