View Issue Details

IDProjectCategoryView StatusLast Update
0003366GCSGeneralpublic2018-06-03 07:58
ReporterManuel Assigned Toabdullah  
PrioritynormalSeverityminorReproducibilityalways
Status closedResolutionfixed 
PlatformArch Linux 
Product Version0.17 
Summary0003366: Constraint angle between Line and Arc (via tangent helper line) doesn't play well with symmetry constraint
DescriptionUsing the constraints symmetry and angle between Line and Arc (via tangent helper line) can cause FreeCAD to detect conflicting constraints upon value change even though the values are valid.
Steps To Reproduce* Download attached FreeCAD file
* Open the contained sketch
* Change the angle constraint (Constraint number 12) by at least 1° (for example to 111°)
* FreeCAD will report conflicting constraints even though the new value should result in a valid sketch
Additional InformationForum thread: https://forum.freecadweb.org/viewtopic.php?f=8&t=27271

Additional note: The order in which the constraints are created seems to matter. Deleting constraint 2 in the attached file (the symmetry constraint at the endpoints of the arc) and recreating it makes the bug disappear.

Installation details:
OS: "Arch Linux"
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.13362 (Git) AppImage
Build type: None
Branch: master
Hash: 8c6b4ad1a60e2af6c1512cd01b6f47620612a5bd
Python version: 2.7.6
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 7.1.0
Locale: German/Germany (de_DE)
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FreeCAD Information

Activities

Manuel

2018-03-10 00:33

reporter   ~0011030

Forgot to upload the fcstd file. Here it is.

Kunda1

2018-03-10 01:35

administrator   ~0011031

Moved to 'GCS' and assigned to abdullah

abdullah

2018-04-27 09:12

manager   ~0011200

The culprit is the edge-to-edge tangency + coincident instead of endpoint-to-endpoint tangency.

It is no longer possible to create such construction (edge-to-edge tangency + coincident) in current FC, as it automatically changes that construction to endpoint-to-endpoint tangency.

With current FC open the sketch and do:
1. Delete constraints 9 and 10 (coincident and tangency)
2. Add a coincident back
3. Add an edge to edge tangency
4. FreeCAD detects this situation and substitutes the constraints created in step 3 with an endpoint-to-endpoint tangency constraint (you will appreciate the coincident has disappeared).

chrisb

2018-04-27 21:29

developer   ~0011213

To be closed as soon as Abdullah's improvements are in master: https://forum.freecadweb.org/viewtopic.php?f=10&t=28370

chrisb

2018-06-03 07:58

developer   ~0011345

https://github.com/FreeCAD/FreeCAD/pull/1429

Issue History

Date Modified Username Field Change
2018-03-10 00:31 Manuel New Issue
2018-03-10 00:31 Manuel Tag Attached: Solver
2018-03-10 00:33 Manuel File Added: bugreport_angle_arc_line_minimal.fcstd
2018-03-10 00:33 Manuel Note Added: 0011030
2018-03-10 01:34 Kunda1 Project FreeCAD => GCS
2018-03-10 01:34 Kunda1 Category Bug => General
2018-03-10 01:35 Kunda1 Assigned To => abdullah
2018-03-10 01:35 Kunda1 Status new => assigned
2018-03-10 01:35 Kunda1 Note Added: 0011031
2018-04-27 09:12 abdullah Note Added: 0011200
2018-04-27 21:29 chrisb Note Added: 0011213
2018-06-03 07:58 chrisb Status assigned => closed
2018-06-03 07:58 chrisb Resolution open => fixed
2018-06-03 07:58 chrisb Note Added: 0011345