Vector troubleshooting
Short answer
Most vector problems are invisible at normal zoom and obvious once you look. Run your CAM's open vector check, its duplicate check, and turn on node display. Those three checks catch the great majority of toolpaths that refuse to generate or come out strange.
The three checks to run on every import
- Open vectors. Most CAM will highlight them and offer to join within a tolerance.
- Duplicates. Two identical shapes stacked on each other look like one and behave like chaos.
- Node display. Turn it on and look at one letter or curve. It tells you immediately whether the artwork is clean or traced.
The problems, and what each one causes
| Problem | What you see | Fix |
|---|---|---|
| Open vectors | Pocket or V-carve refuses to generate | Join vectors within a tolerance, then check again |
| Duplicate vectors | The machine cuts the same path twice, or a V-carve produces nonsense | Run the duplicate check and delete |
| Overlapping vectors | Odd deep spots, or areas that do not clear | Find and remove the overlap, or use a boolean union |
| Self-intersecting paths | Deep spots in V-carving where strokes cross | Union the shape so the crossing becomes one outline. Common in script fonts. |
| Too many nodes | Faceted curves, stuttering motion, slow jobs | Node reduction or curve fitting, then check the shape survived |
| Tiny segments | Same as above, plus enormous G-code files | Simplify, and set a sensible tolerance |
| Text not converted to outlines | The font substitutes on another machine, or will not toolpath | Convert text to curves before toolpathing |
| Stroke instead of fill | An imported outline has thickness that is not real geometry | Expand or outline the stroke in the design program first |
| Wrong scale on import | Everything is 25.4 times out, or a fraction of the size | Measure a known dimension immediately after import |
Tracing an image, done as well as it can be
Tracing is often the only option for a logo you were sent as a PNG. The results depend almost entirely on what you feed it:
- Start with the highest resolution you can get. Ask for the original vector file first. It is worth one email.
- Increase contrast and reduce the image to clean black and white before tracing.
- Remove noise and JPEG artefacts. The tracer will faithfully turn every one into geometry.
- Trace at a moderate detail setting. Maximum detail means maximum nodes, and most of them are describing compression artefacts.
- Simplify after tracing, then zoom in and check corners and curves survived.
- Redraw critical parts by hand. For lettering in particular, retyping it in a real font beats any trace.
A traced logo is not the same as the logo
Tracing produces an approximation. For a customer's brand, small differences in letterforms and curve tension are visible to them even when they are not to you. Ask for the vector original before you trace, every time.Arc fitting
Even with clean vectors, the post processor decides whether curves go to the machine as arcs or as chains of line segments. Arc output is smaller, smoother and faster where the controller supports it. If your curves cut faceted despite clean geometry, check the arc fitting setting in your post. See post processors.