Convert to Polyline?

[Bruce Kieffer]

How do I convert lines to polylines?

[Bob Holtzmann]

It's easy. Select the line segments, and from the Modify Menu, select the Compose command. It will make a polygon, which is similar to a polyline.

If the lines enclose an area, the Combine Into Surface command will also make a polygon.

[Bruce Kieffer]

I will try that, but I've been told that to convert my file to DXF for use on a CNC router, the lines need to be polylines.

[Pat Stanford]

Draw the lines. Make sure the ends are coincident.

Compose. This will get you a polygon.

Go into the Polyline tool and edit the Polyline Preferences. Set the Fillet Radius to the curvature you want at the joints.

Select the polyline.

Use the Modify:Poly Smoothing:Arc Smoothing command to fillet all of the joints to the radius you set in the Polyline tool.

I am not certain, but the radius you want is probably equal to the smallest diameter bit to be used in the machining.

[Bruce Kieffer]

Thanks Pat. That seems to work. I set the radius to .0001 so basically there was no change. I'll have to mess with it and do some testing with the man who has the CNC router. I still need to know if there's a fast way to convert a line to a polyline?

[Pat Stanford]

No, there is no fast way.

A single straight line can not be a polyline as it does not have any curves.

A line is a single straight segment.

A polygon is multiple connected straight segments.

A polyline is multiple connected curved (and possible straight) segments.

I don't know if this is a strict mathematical definition, but it is the VW definition.

I think for the CNC, you need to create as many closed polylines as possbile as that is what the machine understands. If you have four straight lines that make a rectangle, the machine will probably not know what to do, just as VW does not know how to apply a hatch/fill. You have to create a polygon/polyline to do the fill or to run the router.

Send a sample file to the guy and see what he thinks.

[GWS]

Bruce

I've always composed the lines into polygons and then export as DXF which seems to work on the CNC routers I've used. Just make sure, as Pat says, that they are coincident. If there is a gap it wont work.

[Bruce Kieffer]

I'm testing files with the CNC person now. So far so good. We worked out the file export settings to DXF, now we are testing to see if polygons work. Fortunately, none of my shapes are complex, so I can redraw them as polylines easily enough if that's necessary. Thanks for your help.