Hello how do I convert an arc to a straight line on Quad

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hannaconner
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Joined: Tue Jul 01, 2025 10:28 am

Hello how do I convert an arc to a straight line on Quad

Post by hannaconner » Tue Jul 01, 2025 10:30 am

Hello! how do I convert an arc to a straight line.


context: My cnc machine has issues with small arcs, it considers the radius too small, but it has no problem with small straight lines. its a whole lot of work to convert small arcs to lines manually, this there a way of converting a selection of arcs into straight lines?

Thanks

CVH
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Posts: 4874
Joined: Wed Sep 27, 2017 4:17 pm

Re: Hello how do I convert an arc to a straight line on Quad

Post by CVH » Tue Jul 01, 2025 12:25 pm

Hi, and welcome to the QCAD forum.

Many small arcs may be the result of exploding a Spline entity or approximating those.
See Application Preferences .. Modify .. Explode for Spline approximation tolerance.
The lower this tolerance, the more segments are required for an approximation.

If your CNC does not support G2/3 at all I would opt for approximating Splines with Line segments.

QCAD/CAM has a option to not export G2/3 moves, interpolating to line segments.

With only small Arc segments you could try:
Select the path sources and create a polyline from selection (OC).
(Re-)select resulting and convert Arc to to Line Segments. (A Polyline tool, no shortcut availible)
If required, explode (XP) the converted Polyline entities back to individual segments.

This answer by Andrew is another option.
The search term 'discretize' may return more hits.

Even an experimental tool splitting all Arcs into N segments.
An option for a maximal segment length would be better suited for a wide span of Arc shapes.
An arc can be 'discretize' at the outer or at the inner side, the latter has nodes on the Arc.

Regards,
CVH

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