For the life of me I cant seem to get BCC to use K. I'm trying to do a simple arc in XZ and I keep getting multiple lines That simulate an arc. I have turned on 3d in the CAM side, andplayed with the conversion setup. I'm using V20 and MACH3. Please help me, Andrew

If its like Bobcad of old, then likely the K word has been deliberately deleted in your conversion window in nc setup.
There is good reason to do this when you are running a mill and only want arcs with I and J on the G17 plane.

In lathe though, you'll have to undo that conversion. Look down the list of things in the conversion window, and you will likely find one with "K" in the left window and a corresponding blank in the right window. Delete both. Carefully. :D Save it as a new machine post in case you screw it up, you can go back.

You will also have to convert the names of the X axis to Z and the Y axis to X.

Thank you for the reply, I'm running a mill. I deleted the k-*[0-9] thing from the conversion window and it still doesnt use it though. Why cant it just use I and K or J and K.? Andrew

I misunderstood that you were running a lathe :D So ignore that advice I gave above.

Milling arcs in various planes requires a specific gcode command to switch the pairs of axis that are used during circular interpolation (arcs).
G17, G18 and G19 are the switches and these are necessary for your controller's sake. They do not affect Bobcad, though.

Most controls default to G17 mode, which is for arcs in the XY plane.

Now, cutting arcs in other planes means that the arcs must lie only in that plane, and must not have a different end coordinate in the unnamed plane for that particular Gcode switch. In free flowing 3d surface machining, such an option is not terribly useful, because many of the curves straddle all 3 planes.

I cannot recall if Bobcad actually does output the arc coordinates in the YZ or XZ planes. Is there a setting for this in properties or NC setup? The setting would be something along the lines of 'interpolate arcs'....... which breaks the arc into short line segments that your controller can use without switching planes.

You might end up having to hand code such a movement.

I found a way.. I have to use the machine single option. nothing else. Odd, but I can make it work. Thank you Huflungdung for your help and input. Ive been drawing my own tool path for bobcadcam to easyly follow. I draw everything in AutoCAD2005, and all these programs can get very confusing at times. Thank You, Andrew

Also, you can use the Generate NC command from the Special/NC-CAM menu. It isn't wher you would think to look but it is there.

Select your Chain(s) and have your NC-CAM window open. Then click on the Generate NC option. You will have your 3D arc commands for milling generated. Be careful because this option does not take into account the automatic roughing value in the Tool Depth Settings window, so if the part is not roughed and the cutter will not take all the material at once don't use it.

Regards