Where duplicates come from and what they cost
Duplicates come from export and editing: a part pasted onto itself, a contour drawn over a sketch, the same outline on two layers. SendCutSend notes that a duplicate shows as a thickened line and comes from a surface projected more than once during export; TAUPITZ notes that stacked contours often appear during export and asks customers to clean the file before sending it.
If the copy reaches the machine, the beam cuts the same line twice: more time and more heat at the edge. If it reaches a quote that adds up the drawn lines, the cutting price grows with the extra length.
Xometry's DXF guide asks to remove all duplicate or overlapping lines, curves, points or other entities. SendCutSend's automated system rejects files with duplicate paths, MEILLER warns that duplicate lines lead to errors in production, and TAUPITZ writes that open lines, duplicate contours or wrong units lead to miscalculations or manufacturing errors.
How to fix it
The CutMeter check reports each duplicate line with its position. Auto-fix removes the extra copy, so the file you download has each edge once and its cut length equals the measured one.
In CAD, use the command that deletes duplicate objects, or select the edge and look at how many objects are selected. Lines that overlap only partly count too: CutMeter counts the shared part once, and auto-fix writes only the pieces that are not shared.
Worked example
A 100 × 100 mm square drawn as four lines, with the top edge drawn a second time.
Adding up every entity gives 500 mm. CutMeter counts 400 mm in one closed contour and reports one issue: a duplicate line, fixable.
After auto-fix the file has 400 mm of lines: the machine cuts what was measured.
Drawn length and cut length
| Measure | Value |
|---|---|
| Sum of all drawn lines | 500 mm |
| CutMeter cut length | 400 mm |
| Written by auto-fix | 400 mm |
| Issue reported | Duplicate line |
Check a DXF for duplicate lines
Questions
What is a duplicate line?
Two entities on the same path: a line, arc or curve drawn twice, completely or in part. On screen they look like one.
How do I see a duplicate if it looks like one line?
Select the edge and look at the number of selected objects, or run a check: CutMeter lists every duplicate with its position.
Does a duplicate make my quote higher?
In a quote that adds up the drawn lines, yes: the extra length is priced. CutMeter's cut length counts every edge once, so the quote follows the part, not the drawing.
What about lines that overlap only partly?
CutMeter counts the shared part once. Two closed contours that cross each other are a different problem: the check marks them as overlapping contours, and they must be corrected in CAD.
Is it safe to remove duplicates automatically?
For exact copies, yes: the part keeps its shape and the cut length does not change. Look at the drawing after the fix anyway; a person signs off the file, not the software.
Sources
- Xometry: Guide to Quoting with DXF Files xometry.com
- SendCutSend: What are common problems to look for in my files? sendcutsend.com
- MEILLER: Laserteile richtig als DXF-Datei anlegen (German) meiller-lasertechnik.de
- TAUPITZ: Welche Dateiformate eignen sich für die Blechfertigung? (German) taupitz.com
- TAUPITZ: Rohrabwicklung erstellen: Was ist bei komplexen Konturen zu beachten? (German) taupitz.com