Resolving OpenBuilds CAM Arc Connector Cut Lines Guide

OpenBuilds CAM shows cut lines along a straight connector between points on an arc after you convert the drawing to G-code. First determine whether you are seeing a toolpath display overlay or a connector that is actually present in the generated moves; hiding the overlay does not repair incorrect geometry or G-code.

Check whether the lines are only a toolpath overlay

1. Save a copy of the project before changing display or geometry settings.
2. Inspect the toolpath display options. The reported interface has a checkbox below Toolpaths; turning it off hides the tool lines.
3. Compare the drawing with the toolpath view. If the connector disappears when tool lines are hidden and the drawing itself remains correct, you have hidden a display layer, not changed the generated machining path.
4. To decide whether the machine would cut that connector, inspect the generated G-code or use the CAM preview with toolpath display enabled. Look for a cutting move between the arc-related points rather than relying on the overlay alone.

Do not treat unchecking the toolpath option as a fix for a cut that appears in G-code. It only makes the lines less visible in the interface.

Inspect the imported vector where the connector appears

Zoom in on the arc and its endpoints in the source drawing. Compare the geometry before and after import, especially where the straight connector meets the curve. A drawing can look like a clean arc at normal zoom while containing separate segments, an open contour, or an unintended straight edge.

• If the straight line is already part of the imported vector, correct or replace that geometry in the drawing application, then re-import it.
• If the imported drawing shows only the intended arc, continue to check how CAM interprets the contour and selected toolpath operation.
• If the connector appears only in the toolpath or G-code, inspect the generated moves before running the machine.

Vector files may represent curves as native arc entities or as many short line segments. A visually smooth curve does not prove that the contour is topologically continuous or that every segment belongs to the intended cut.

Check contour continuity and direction

Determine whether the arc endpoints form a continuous contour with the adjoining geometry. CAM software creates toolpaths from vector entities and their connectivity; a gap, duplicate segment, overlapping endpoint, or unintended chord can make the resulting path differ from the visible shape.

• If the connector joins two endpoints that should meet, close or join the contour in the source drawing and import it again.
• If the connector bridges unrelated endpoints, separate the contours or remove the unwanted entity before generating the toolpath.
• If the contour is correct but the toolpath still adds the line, check which vectors are selected and which machining operation is applied.

After editing, regenerate the toolpath from the corrected geometry. Do not edit only the preview and assume the source vectors changed.

Compare the generated moves with the intended cut

Read the G-code around the location of the unwanted line. Identify the move sequence that enters the arc, follows it, and exits it. A visible straight move can be a rapid repositioning move, a cutting move, or simply a drawn toolpath overlay; the move type and cutting state distinguish them.

• If the connector is a non-cutting reposition, confirm the CAM output marks it as a rapid move and that the machine preview shows it above the work.
• If it is a cutting move, return to the vector and toolpath selection checks; the CAM is being instructed to machine that segment.
• If the G-code path is correct but the preview still shows a connector, refresh or regenerate the preview after saving the project and confirm you are viewing the current toolpath.

Never infer that a line is harmless from its appearance or color alone. Verify the actual move in the generated file and the CAM's interpretation before cutting.

Regenerate and verify the corrected path

1. Correct the source vector, contour closure, or selection identified by the checks above.
2. Save the drawing, re-import if required, and regenerate the toolpath and G-code.
3. Inspect the arc at high zoom in the drawing and toolpath views. Confirm the unwanted connector is absent from the cutting path.
4. Review the G-code moves at that location and confirm any repositioning move is non-cutting.
5. Run the CAM preview through the arc before machining. If the preview and G-code disagree, stop and resolve the discrepancy rather than testing it on the workpiece.

Do not waste time toggling visibility settings when the G-code contains a cutting move along the connector. Likewise, do not redraw a correct arc until you have checked whether the line is merely a display overlay.

OpenBuilds CAM cut-line questions