Can't say anything about RhinoCAM - I have used an older version of Rhino itself (v4, I think) and concluded that as an engineering CAD application it didn't suit me - but I'm sure that things have moved on a lot since then. However, my copy of Vcarve produced a gcode file - and this was just for finishing, not roughing - of just under 50000 G1 straight-line moves in 3D and the finished item shows no sign of facets, so while it might not be perfect, it is perfectly capable of doing the job. My starting point was a rectangular grid approx 150x120mm with heights at 1 mm intervals, so the actual mesh model was relatively coarse, and the CV function in the motion controller smoothed it all out and there was no jerkiness or other roughness in the cutting process. So I don't that think that the way Nickn has produced his gcode is, in itself, flawed even though there might be better methods of generating the model. I guess it comes down to whether you want to do the smoothing as part of the model generation or while processing the gcode. I have no view there except that I've found a way that works for me!

As for where to find the setting - I could tell you how using Mach3 or myCNC (the two motion control applications I use) and I'm sure it would be easy to find for UCCNC. but I have no idea what AXYZ use or what their control panel looks like. But a controller that does not have this option sounds unlikely, so it must be there somewhere!