One other way that I have found is go to advanced in surface parameters and check roll tool only between surfaces (solids) instead of automatically. You can then use entry exit arc to give your lead in/out. This will do what you want.

Have more info on this problem. On the mc. handy codes card that comes with the software G18 is listed as zx plane where the mpmaster post uses xz. This is important because it reverses the rotation of arcs screwing up the job. I backplotted a job watching the colours to see the direction of the arcs and mc. definitely uses zx not xz. I then switched my centurian 6 controller to zx instead of xz and it now machines the arcs the right way. I have to say though I am afraid to filter because its like a box of chocolats you never know what you are going to get.

Hey I'm back: I just downloaded the latest v9.04 and changed arccheck to 3 in the post. I am pleased to say my problem has disapeared. I will keep you informed if I encounter this situation in the future in some other file. Thanks

I made the changes suggested by Zero and the mistake percentage has improved. The latest mistake I have seen is right on the screen toolpath doing a simple 2d contour using the ramp down feature. I had 10 pieces on the screen 6 were correct and on 4 of them the toolpath took off into the part on one end of the piece. The difference this time is it showed up on the screen. When I shut off filtering the toolpath was correct. My controller is set to G18 is xz plane which corresponds to the mpmaster posts [ 05-03-2002, 12:05 PM: Message edited by: Gmbill ]

I am using MC v9 with the mpmaster post with a few minor alterations to suit a centurian 6 controller on a 3 axis mill. If I try to filter the output code to create arcs rather than jumpy lines mastercam tends to mix up G03 and G02 so the arcs go in the wrong direction. You do not see this error on screen but it machines incorrectly and looking at the code produced it is wrong. Am I the only one suffering from this problem? Is there any way to adjust the post to not allow this error? Even just filtering in the x,y, plane it will make this mistake the odd time.