Folks: I have a problem setting up a rotary axis (x,y,z,a) in MADCAM/Rhino6. I can set up MADCAM in 4 axis mode but when I create a toolpath (e.g. cylinder planar cut oriented along the Y axis) the toolpath is not what I expect. The toolpath looks OK in the simulation ie it cuts with the tool on top Z with A axis rotating but the X and Z values do not stay on "top" of the cylinder but rotate around the cylinder including the bottom. I think I know what is happening, the X,Y, and Z axes are "rotating" with the A axis since the coordinates are in "absolute" mode. This is a problem after postprocessing (mach3 4 axis rotary) in that the CNC machine uses the A, x, y, z values and runs around the cylinder including the bottom so it tries to cut through the stock. I appears that I need to run MADCAM in "relative units" mode so that the coordinate system does NOT rotate. I have looked on line, in forums et al. but can not find an appropriate setting in MADCAM or Rhino. This is such a fundamental question that I am sure it has been addressed many times before but I can not find a solution. I would appreciate some help on this as it makes my rotary axis useless.

Thanks

JRS_CNC