Did I show you this link already?
http://www.machsupport.com/forum/index.php/topic,10308.0.htmlThe toolpath will display what the code tells it to. However if you have an axis reversed it can flip, mirror, or make opposite hand parts. Draw out a word parallel to the x axis to cut and then reverse your x and cut the part. It will be perfect............ if your viewing it through a mirror. Now reverse Y and cut another. It will now be mirrored and up side down. The toolpath with the exact same code will display no different if you have your axis reversed or not. Mach isnt smart enough to figure out which way is + and which is -, we have to do that. Its just smart enough to go where we tell it to. If we tell it turn right when it should turn left........... you know what that does.
Brett