Splitting nearest overlapping edge without trimming

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AndroYD
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Joined: Fri Nov 25, 2022 7:57 am

Splitting nearest overlapping edge without trimming

Post by AndroYD »

Code: Select all

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/Hong Kong (en_HK)
Installed mods: 
  * CfdOF 1.18.0
I can't find an equivalent option to the "Trim Edge" tool (in the Sketcher menu https://wiki.freecadweb.org/Sketcher_Trimming) that preserves the trimmed part (it gets deleted by default).
This how I want to accomplish it in my head.
SketcherTrimNoRemoveExample1.png
SketcherTrimNoRemoveExample1.png (3.35 KiB) Viewed 641 times
SketcherTrimNoRemoveExample2.png
SketcherTrimNoRemoveExample2.png (3.41 KiB) Viewed 641 times
SketcherTrimNoRemoveExample3.png
SketcherTrimNoRemoveExample3.png (4.1 KiB) Viewed 641 times
The Split edge tool https://wiki.freecadweb.org/Sketcher_Split doesn't seem an option, because it creates new points BESIDE the intersection (not EXACTLY ON the intersection), so attempting to constrain the point later to the desired spot may alter the original sketch position/shape (especially with curved lines), even if by a little bit, I do not want that.
I've searched extensively for days and I can't find any reliable method, been using FreeCAD for 3 months now, I want to keep those lines unaltered as much as possible so I can keep them as construction lines to develop my sketch or constrain it more easily.
chrisb
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Re: Splitting nearest overlapping edge without trimming

Post by chrisb »

Hi and welcome to the forum!

If these points are just construction aids, why not add a point on the intersection?
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
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AndroYD
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Re: Splitting nearest overlapping edge without trimming

Post by AndroYD »

chrisb wrote: Sat Nov 26, 2022 2:29 am If these points are just construction aids, why not add a point on the intersection?
Because in some situations the point already exists, I just want to split the line at the intersection (without destroying anything), here's a simple case example.
GIF 26-11-2022 10-51-05 am.gif
GIF 26-11-2022 10-51-05 am.gif (208.77 KiB) Viewed 620 times
I had to recreate the destroyed line again, I find this very inconvenient. What if the line wasn't destroyed in the first place?
chrisb
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Re: Splitting nearest overlapping edge without trimming

Post by chrisb »

What I see in the animation could well be done with Sketcher Split, but even if you want to split exactly on a crossing, I still don't see the full use case. It still seems very rare to me, so you may get it done with a different order of constraining.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
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AndroYD
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Re: Splitting nearest overlapping edge without trimming

Post by AndroYD »

chrisb wrote: Sat Nov 26, 2022 6:46 am What I see in the animation could well be done with Sketcher Split
GIF 28-11-2022 11-55-35 am.gif
GIF 28-11-2022 11-55-35 am.gif (191.81 KiB) Viewed 490 times
The Split Edge + Constrain coincident tool approach carries the risk of moving stuff, the trim edge doesn't. As the complexity of the sketch grows, so are the number of variables to account for. IMO, the value of a tool is also how it can help people avoid/correct stupid mistakes.
chrisb wrote: Sat Nov 26, 2022 6:46 am but even if you want to split exactly on a crossing, I still don't see the full use case.
GIF 28-11-2022 12-59-40 pm.gif
GIF 28-11-2022 12-59-40 pm.gif (123.18 KiB) Viewed 490 times
Case in point, how do I efficiently convert these lines into construction lines? It's already fully constrained. Usually circular repetitive parts can be built using polar arrays, but I can't rely on them this time.
chrisb wrote: Sat Nov 26, 2022 6:46 am It still seems very rare to me, so you may get it done with a different order of constraining.
People on wheelchairs are rare cases too, so no one should account for them when designing a building or a bus? I don't expect them to Tony Hawks into them just because it's technically possible.
It honestly feels like screwing a lightbulb by rotating the house kind of scenario, with all due respect, after hours of searching tutorials, videos and this forum, I come up asking for help making gifs and presenting my case very clearly and I still can't find an answer, all that effort just for... splitting a line at an intersection/edge?

I fully understand you have no obligations, and are only volunteering your time and that much more time was spent on making FreeCAD overall than I've spent on this particular issue, I'm truly grateful for that, I'm just really tired so please don't take that as an offense.
Bance
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Re: Splitting nearest overlapping edge without trimming

Post by Bance »

Easy answer don't make complex sketches, they are almost always not necessary.
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onekk
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Re: Splitting nearest overlapping edge without trimming

Post by onekk »

AndroYD wrote: Mon Nov 28, 2022 7:58 am ...
Some times, like in this case correct question is not:
how to do...
But:
I have to get this..., how I can made it with FreeCAD?
As probably there are better ways in a complex program like FreeCAD to do things, and probably the workflow you follow in another program is not correct for this program, as most probably something is different "behind the curtains", and there are "solid" reason to do things.

Part Design will follow "feature driven design" concepts, see maybe:
https://wiki.freecadweb.org/Feature_editing

The sketch you showed, probably has to be made into a solid.

Here a possible solution that use two sketch, two extrusion and a polar pattern and that probably will do the job.

As you not everytime you have to make the sketch of the final part:

20221128_polar.FCStd
(32.85 KiB) Downloaded 10 times
polar.png
polar.png (12.27 KiB) Viewed 453 times

Regards

Carlo D.
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papyblaise
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Re: Splitting nearest overlapping edge without trimming

Post by papyblaise »

or in once
Attachments
roue maçonique.JPG
roue maçonique.JPG (20.98 KiB) Viewed 411 times
roue maçonique.FCStd
(42.9 KiB) Downloaded 7 times
GeneFC
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Re: Splitting nearest overlapping edge without trimming

Post by GeneFC »

AndroYD wrote: Sat Nov 26, 2022 1:42 am I can't find an equivalent option to the "Trim Edge" tool in the Sketcher menu that preserves the trimmed part.
The simple answer is that this option does not exist. You can make a feature request, of course.

There is a bit of a workaround that may be useful in some cases. If the two intersecting lines from your first example are fully constrained apply a split to one of them. The split point can be easily moved to the intersection by use of the "Constrain point on object" tool.

If the end points of the initial lines were not fully constrained it is likely they will move when the point-on-object tool is used.

Gene
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