I have recently been using more gcode with curves rather than lots of straight segments..
I have noticed that when the toolpath display shows these toolpaths, instead of drawing a curved radius where a curve should be, it draws a massive circle on the same trajectory of the curve extending out from the correct start and end point and leaves out the segment where the curve would be as if its travelling from the start to end point round the center point the wrong way, the program still seems to follow the correct path, leaving the little white dots behind in the right place.
 Also when i make a toolpath with straight lines making up curves, the machine runs smooth and continuous on paths in xy plane but is jumpy (starts and stops) in yz and xz plane.
any ideas
regards
Benergy