Good afternoon all,
I have been looking at Non-Planer Slicing for a while, and there are some out there.
The one I like very much and it has worked for me very well is Curvislicer.
https://github.com/mfx-inria/curvislicer
It works in Windows 10, it is command line based, it is bit rough at the beginning, but it really works great, it prints in real 3D from the start.
What I have done so far is slice the object in Cura first, then do it with Curvisliser, edit the GCODE file and add the ones you like from Cura GCODE to the newly sliced GCODE from Curvislicer, and off you send it to the 3D printer.
Make sure you will have enough clearance on you printer Hotend to avoid physical collisions.
Read instructions and you will see how beautiful the result would be.
Good luck
Siamak