Merge collinear: when to turn it on
Merge collinear drops redundant points on straight runs before the toolpath is built. Fewer stops, smoother cuts, smaller PLT files — and it never eats a real corner.
How it works
A point is removed only when it and its two neighbours lie on one straight line pointing the same way. Corners and fold-backs are always preserved, so the outline cannot lose its shape — the operation only removes points that added nothing.
Leave it on (default)
- Traced bitmaps, where the tracer emits many tiny segments along what is visually a straight edge.
- Imported PLT or DXF files from other software, which are often over-segmented.
- Any job where the machine stutters or the file is unexpectedly large.
When to turn it off
- Engraving-style outlines where the micro-segments are intentional texture.
- Artwork with deliberate stair-stepping that must survive as-is.
Checking the result
- Tick Merge collinear in the send dialog — it is on by default.
- Open the toolpath preview. Merged runs appear as single long segments.
- Send, then compare the first piece against the previous run: same shape, fewer stops.
If a corner disappearedIt was not a fold-back, it was three points that genuinely formed a straight line. Check the source curve — the merge cannot create a shortcut that was not already there.
With shared edges
Both operations shorten the path in different ways: shared edges remove duplicate lines between neighbouring pieces, merging removes redundant points along each line. Turning both on is normal and gives the cleanest result.