Two-levels answer about :
- if it's only one line whose thickness changes, it's very easy to do such visualization with BeGraphic (e.g.: Napoleon's march to Russia)
- if you are talking about energy flow designed by the irish Captain Matthew Sankey where several lines are always touching each other
- even if their thickness change, then the current version of BeGraphic doesn't have it anymore.
"BeGraphic Pro V1" used to have a "magnet" function that helped user to build custom Sankey diagrams (With BeGraphic each line can change its thickness ; but with the new "Magnet function", the second line begins where the first one finishes). But users didn't understand it and asked for a ready-made template to use a Sankey diagram. Therefore we will redesign it later.