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IDProjectCategoryView StatusLast Update
0002509PartBugpublic2021-02-06 06:46
Reportergdolle Assigned To 
Status confirmedResolutionopen 
PlatformLinuxOSArchlinuxOS Versionx86-64
Target Version0.20 
Summary0002509: Sweep using bezier curve bug
DescriptionCreate a pipe using bezier curve. Depending on geometric point placement, the sweep bugs.

OS: "Arch Linux"
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.Unknown
Build type: Release
Python version: 2.7.11
Qt version: 4.8.7
Coin version: 3.1.3
OCC version: 6.9.1
Steps To ReproduceSimple case:

1) Create a bezier curve using 4 points aligned (2 vertex, 2 geometric).
2) Create 2 disks placed to the curve extremities.
3) Create a sweep with the two disks along the bezier curve.
Additional InformationSee the joint example in the FreeCAD file and a screenshot
Tags#pending, bezier curve, sweep
FreeCAD Information


related to 0002187 closedChris_G FreeCAD Sweep tool fails with Frenet=True on special Wire created from Section 



2017-01-18 01:10


bug1.fcstd (184,262 bytes)


2017-01-18 01:11


screen.jpeg (152,020 bytes)   
screen.jpeg (152,020 bytes)   


2017-01-18 01:15

administrator   ~0007858

Forum thread:
I also edited the ticket by removing the tar and re-uploading the screenshot and .fcstd separately.


2017-02-17 03:56

manager   ~0008329

See my tests in the forum topic:

The gist of it is that forcing the BezCurve to be straight is probably what's causing the issue. I really can't see how producing such a "straight curve" would be desirable. If you want a straight path, why not create a line? When creating a Draft BezCurve with only two end points, the object that is automatically created is a Draft Line rather than a BezCurve.

The same issue with the sweep applies to a B-spline with 4 poles constrained to be straight. But a B-spline with two poles produces a valid sweep.

What needs to be decided: is the use of a straight BezCurve with more than 2 points an appropriate use here; only then can this be considered a bug. But that is for the developers with deep knowledge of such geometry to decide...


2017-02-17 11:00

reporter   ~0008331


Yes, there's a point. The idea was to curve this line after the sweep (The idea is that the curvature is not determined and can change in my current usage).
It was some times ago, but if I remember, it was not possible to convert a straight line to a BezCurve (at least if you already create the sweep on the straight line).

Also if I remember what I was doing, there was some bugs with BezCurve boolean depending on the curvature, so I wanted to create a straight BezCurve, then curve it.


2017-04-28 01:57

administrator   ~0008786

@kkremitzki please create a Part project and move this ticket in to it. Thanks!


2017-05-16 14:45

administrator   ~0009033

@Kunda1 moved


2019-03-06 11:29

administrator   ~0012854

@Chris_G care to take a look at this issue? It supposedly is related to 0002187


2019-09-01 19:17

administrator   ~0013510

the sweep path has some straight segments, that have a normal plane, but no unique normal vector ( which is needed for Frenet ).
IMHO, this is an OCC bug. A nurbs or Bezier curve with poles aligned is perfectly valid.

per @Chris_G's response in the forum thread


2019-09-01 19:18

administrator   ~0013511

@abdullah can I put this on your radar to take a look at ?


2022-03-03 13:55

administrator   ~0016486

This ticket has been migrated to GitHub as issue 5651.

Issue History

Date Modified Username Field Change
2016-04-15 16:54 gdolle New Issue
2016-04-15 16:54 gdolle File Added: bug_sweep_bezcurve.tar
2016-04-15 16:55 gdolle Tag Attached: bezcurve
2016-04-15 16:55 gdolle Tag Attached: sweep
2017-01-17 17:19 Kunda1 Tag Renamed bezcurve => bezier curve
2017-01-18 01:10 Kunda1 File Added: bug1.fcstd
2017-01-18 01:11 Kunda1 File Added: screen.jpeg
2017-01-18 01:11 Kunda1 File Deleted: bug_sweep_bezcurve.tar
2017-01-18 01:12 Kunda1 Additional Information Updated
2017-01-18 01:15 Kunda1 Note Added: 0007858
2017-02-16 12:17 Kunda1 Tag Attached: #pending
2017-02-17 03:56 normandc Note Added: 0008329
2017-02-17 11:00 gdolle Note Added: 0008331
2017-02-17 13:47 Kunda1 Relationship added related to 0002187
2017-04-28 01:57 Kunda1 Note Added: 0008786
2017-04-28 01:58 Kunda1 Status new => confirmed
2017-05-16 14:42 kkremitzki Project PartDesign => Part
2017-05-16 14:42 kkremitzki Category Bug => General
2017-05-16 14:44 kkremitzki Category General => Bug
2017-05-16 14:45 kkremitzki Note Added: 0009033
2019-03-06 11:29 Kunda1 Note Added: 0012854
2019-09-01 19:17 Kunda1 Note Added: 0013510
2019-09-01 19:18 Kunda1 Note Added: 0013511
2021-02-06 06:46 abdullah Target Version => 0.20