Thanks everyone for your helpful questions.....
Some answers are:
Yes, I do see lines after importing the model into VCarve software. So I guess possibly the triangulation resolution I'm exporting from AutoCAD isn't fine enough.
I tried setting up the finest modeling resolution in VCarve, but that didn't change anything.
Even with a fine finishing pass in the highest resolution, the lines are still there.
I'll try a higher triangulation resolution export from AutoCAD and let you know how it works....if I can figure that out