Problem Trimming BSplines create in Draft Workbench

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daffyduck
Posts: 24
Joined: Mon Jul 26, 2021 12:52 am

Problem Trimming BSplines create in Draft Workbench

Post by daffyduck »

Hello all! :-)

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OS: Windows 10 Version 2009
Word size of FreeCAD: 64-bit
Version: 0.20.1.29410 (Git)
Build type: Release
Branch: releases/FreeCAD-0-20
Hash: f5d13554ecc7a456fb6e970568ae5c74ba727563
Python 3.8.10, Qt 5.15.2, Coin 4.0.1, Vtk 8.2.0, OCC 7.6.3
Locale: English/United States (en_US)
Installed mods: 
  * Assembly4 0.12.4
  * CurvedShapes 1.0.4
  * Curves 0.6.4
  * lattice2 1.0.0
  * Manipulator 1.4.9

Looking for some guidance on an issue that I am having. I trace an image using bsplines in the Draft workbench. Let's say I use the BSpline to create a closed geometry shape. When I want to trim a spline I create a line at the intersection point. I then use the Part Design Workbench Compound:Slice Apart command. At first look this appears to work correctly however if you zoom in really close the command causes gaps in the line(s) it split. This is problematic for example when I need to combine the lines and then extrude the face. Anyone else have this issue or guidance to share?

I hope the answer is not to "Use Sketcher" because I cannot convert this geometry to a Sketch properly, plus that would cause me to recreate a bunch of complex projects.

Appreciate your input!

Thanks.
Attachments
2022-12-06 12_36_19-FreeCAD 0.20.1.png
2022-12-06 12_36_19-FreeCAD 0.20.1.png (19.01 KiB) Viewed 966 times
2022-12-06 12_36_50-FreeCAD 0.20.1.png
2022-12-06 12_36_50-FreeCAD 0.20.1.png (19.94 KiB) Viewed 966 times
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Roy_043
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Re: Problem Trimming BSplines create in Draft Workbench

Post by Roy_043 »

In such cases you really need to post a sample file.
daffyduck
Posts: 24
Joined: Mon Jul 26, 2021 12:52 am

Re: Problem Trimming BSplines create in Draft Workbench

Post by daffyduck »

Thanks @Roy_043 !

I think I am narrowing down the root cause. Totally understand about uploading a file. However I have found it is not a problem with the slice at all. It actually is a snapping problem. In the attached image you can see that the snap location is not even on the line. So the line is never connected in the first place. The image (attached) is just simply trying to start a bspline at a location along a simple straight line. The only SNAP tool I have on is "Snap Near (ON)". Not sure how to solve this one.

If the attached FreeCAD file, if you zoom in as far as you can at the line intersection inside the red circle you will see that the line has a gap.

Thanks.
Attachments
2022-12-06 18_36_42-FreeCAD 0.20.1.png
2022-12-06 18_36_42-FreeCAD 0.20.1.png (42.98 KiB) Viewed 881 times
snapping_test.FCStd
(10.55 KiB) Downloaded 12 times
GeneFC
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Joined: Sat Mar 19, 2016 3:36 pm
Location: Punta Gorda, FL

Re: Problem Trimming BSplines create in Draft Workbench

Post by GeneFC »

Are you sure there is really a problem?

Are you zoomed in to nanoscopic levels to see these problems?

The display rendering in FreeCAD has a certain degree of coarseness to maintain acceptable performance. If you use an extreme zoom it is likely that you can see this sort of apparent mis-target in many places. By itself there is no issue.

If you are seeing a specific computational problem it would be best to focus on that issue rather than the display coarseness.

Gene
daffyduck
Posts: 24
Joined: Mon Jul 26, 2021 12:52 am

Re: Problem Trimming BSplines create in Draft Workbench

Post by daffyduck »

Hi @GeneFC ,

Thanks for the input.

Yes I am sure this is the problem. I cannot create a face due to the issue. When I correct the gap, the face generates with no issues.
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Roy_043
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Re: Problem Trimming BSplines create in Draft Workbench

Post by Roy_043 »

The inaccuracy of Draft_Snap_Near has already been fixed. But the fix could not be backported. So you need to switch to the weekly or use a workaround (see: Draft_Snap_Near).
daffyduck
Posts: 24
Joined: Mon Jul 26, 2021 12:52 am

Re: Problem Trimming BSplines create in Draft Workbench

Post by daffyduck »

Thanks for the info @Roy_043 .

I will test the weekly build.
heda
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Re: Problem Trimming BSplines create in Draft Workbench

Post by heda »

and Draft_Edit does not allow you to get where you need to be?
daffyduck
Posts: 24
Joined: Mon Jul 26, 2021 12:52 am

Re: Problem Trimming BSplines create in Draft Workbench

Post by daffyduck »

Hi @heda,

Thanks for the note. No draft edit did nothing for me. Besides the point is to slice the line and move on without any extra work.

@roy_043 I tested out the nightly build and ran some test. Seems to be working fine. Thanks for the suggestion.

Thanks for the support everyone!

:)
daffyduck
Posts: 24
Joined: Mon Jul 26, 2021 12:52 am

Re: Problem Trimming BSplines create in Draft Workbench

Post by daffyduck »

I am reviving this thread as I seem to have issues that are very similar if not exactly the same as this original problem. (Stated at the top of the thread) I have updated to version 0.021.1. I have created a mesh cross section. I cannot create a line at the intersection of the cross section curves. Additionally if I set the working plane to the same plane that created the cross section, create a wire, then I also get a wire is not closed or wire is not co-planar error. Not sure how to fix this. Screenshots attached. I tried to upload my FCStd file but I get an error message that it is too large. The file size is 1,230KB. Here is my config:

Code: Select all

OS: Windows 10 build 19045
Word size of FreeCAD: 64-bit
Version: 0.21.1.33668 +26 (Git)
Build type: Release
Branch: (HEAD detached at 0.21.1)
Hash: f6708547a9bb3f71a4aaade12109f511a72c207c
Python 3.8.10, Qt 5.15.2, Coin 4.0.1, Vtk 8.2.0, OCC 7.6.3
Locale: English/United States (en_US)
Installed mods: 
  * Assembly4 0.12.5
  * CurvedShapes 1.0.4
  * Curves 0.6.6
  * fasteners 0.4.54
  * lattice2 1.0.0
  * Manipulator 1.5.0
Attachments
2023-10-13 10_51_08-FreeCAD 0.21.1.png
2023-10-13 10_51_08-FreeCAD 0.21.1.png (485.66 KiB) Viewed 287 times
2023-10-13 10_50_46-FreeCAD 0.21.1.png
2023-10-13 10_50_46-FreeCAD 0.21.1.png (135.16 KiB) Viewed 287 times
2023-10-13 10_48_25-FreeCAD 0.21.1.png
2023-10-13 10_48_25-FreeCAD 0.21.1.png (10.96 KiB) Viewed 287 times
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