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Straight Lines instead of G2 or G3

Posted: Fri Nov 16, 2012 3:22 pm
by suntzu626
I'm trying to generate G Code for a series of ellipses cut out of some material on my Accu-Cut Model 510 router with Mach3 and no matter what post processor I use, even if it has the G2 and G3 commands, the G Code is still generated as thousands of tiny straight lines rather than two clean arcs. Don't know if it is due to how I drew the ellipses or generated the tool path. I've tried a bunch of different PP files and none seem to give me the arc moves. Please help.

Re: Straight Lines instead of G2 or G3

Posted: Fri Nov 16, 2012 3:32 pm
by Adrian
The shapes you've created are made from bezier curves not arcs so no arc commands will be generated. If you go into node editing (press N) you can look at the spans and nodes to see how they're made up.

The attached file shows two circles, one made from beziers and one from arcs.

Re: Straight Lines instead of G2 or G3

Posted: Fri Nov 16, 2012 3:41 pm
by suntzu626
Ok so how would I draw these shapes in a way that would give me arcs?

Re: Straight Lines instead of G2 or G3

Posted: Fri Nov 16, 2012 3:47 pm
by Adrian
I doubt you will be able to but if you want to try you can go into node edit and hover over each span and press A (or right click) to convert the bezier span to an arc.

I don't see how you're going to get a shape like that with an arc though I'm no expert with them.

Re: Straight Lines instead of G2 or G3

Posted: Fri Nov 16, 2012 4:23 pm
by rscrawford
You can convert your curves to arcs by using the 'fit curves to vectors' tool. This allows you to fit arcs or bezier curves to any vectors you select, and you can choose the tolerances

edit, I just saw that this was posted under Cut2D. Not sure this tool is in Cut2D.

Re: Straight Lines instead of G2 or G3

Posted: Fri Nov 16, 2012 4:45 pm
by suntzu626
I tried drawing the ellipse in a different program with arcs and not bezier curves then importing the .dxf file into Cut2D and the G Code comes out the exact same way: all G1, not G2 or G3.

Re: Straight Lines instead of G2 or G3

Posted: Fri Nov 16, 2012 5:08 pm
by Adrian
Go into node edit and look at those new shapes. There are hundreds of nodes not arcs.

The attached file is the closest I could get to your shape using arcs.

Re: Straight Lines instead of G2 or G3

Posted: Fri Nov 16, 2012 5:45 pm
by suntzu626
That shape works, thank you so much for the help :)

Re: Straight Lines instead of G2 or G3

Posted: Thu Feb 14, 2013 7:25 am
by aironeous
This is quite annoying to not have this functionality in cut2d. I'm trying to do the butterfly puzzle and simply profiling half the shapes becomes a 1 megabyte gcode file for the HAAS mill at my school. At least I know the problem now.

Re: Straight Lines instead of G2 or G3

Posted: Thu Feb 14, 2013 10:04 am
by Adrian
The functionality is all there in Cut2D it just has to be done manually rather than using a one click tool.