infill density transition

[curasurf 5]

By setting Gradual Infill Steps, the infill density can be changed along Z axis. After examining the printing preview, I'm aware that there is nothing magic in the density transition, but simply printing new infll of higher density on the infill of lower density. Therefore at low densities, e.g. from 2% to 5%, the transition seems to be challenging.

 

I wonder whether there is something like Tree support for the density transiftion at low infill density? Thanks!