Is it possible to Trim Edges while preserving constraints ? [solved]

[FredCailloux]

Just as there is an option in the FreeCAD Sketcher to Constraint-Preserving Sketch Filet,
Is there a way to Constraint-Preserving Trim Edge ?

If not, that would certainly be a great feature suggestion, I think.

[chrisb]

This proposal is a bit general. Can you specify in more detail what should be done?

[FredCailloux]

This proposal is a bit general. Can you specify in more detail what should be done?

When you build a sketch, many lines could cross others at different angles and or cross circles. Once fully constrained It is possible to cut some continuous lines at intersections of circles or other lines using the Sketcher tool “Trim edge”. After removing part of that line the sketch is no longer fully constrained.
It may be easy to re-constrain the sketch when it is a simple one, but when the sketch is complicated it often become a non-trivial task.
Often I found myself building a rather complicated sketch up to full constraint and the finishing touch is to slice several lines to arrive at the final desired result. If there was an option that would automatically retain the full constraint of the sketch even after trimming some lines it can make the job much easier.
Of course, there are situations where you do not want that automation. Just like the Constraint-Preserving-Sketch-Filet tool it would be handy to have a similar option where you can cut a line while preserving the fully constrained status.
Is this, at all, possible ?

[onekk]

This proposal is a bit general. Can you specify in more detail what should be done?

....but when the sketch is complicated it often become a non-trivial task.
...

The point is usually that with "feature driven" build like in typical Part Design workflow, complicate sketch should not exist at all.

If a sketch is too complicated, probably same thing could be for sure obtained with some more simple sketches, and some features applied.

This is a thing that most skilled users of Part Design WB have told countless time.

Regards

Carlo D.

[FredCailloux]

This is a thing that most skilled users of Part Design WB have told countless time.
Carlo D.

Point well taken.
I found that through another question where the same suggestion was proposed.
I find I build sketches way too complicated.
Many simple sketches are more productive and easy to debug than trying to put all details onto a single sketch.
thanks

[chrisb]

When you build a sketch, many lines could cross others at different angles and or cross circles. Once fully constrained It is possible to cut some continuous lines at intersections of circles or other lines using the Sketcher tool “Trim edge”. After removing part of that line the sketch is no longer fully constrained.

I didn't mean to elaborate on the reasons why you would need it, that is important too, but for a feature request, it could be helpful if you show on one of the complicated examples you talked about, what an automated tool should do.

[bleber]

I have a relative simple fully contrained sketch only 2 shapes rectamgle and circle.
When trim the unneded segments I lose the fully constrained sketch.
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Captura de pantalla 2023-11-17 225913.png (41.01 KiB) Viewed 925 times

[chrisb]

It is of course clear, that you as a human being want in this case a tangent constraint. But I’m not sure if this should be done always and it needs quite some geometric knowledge to see this.
The solver does not work algebraically, but by approximation, and I’m not sure if this inverse application (find a certain situation and create a constraint) should be applied here.

[bleber]

In these case the constraint already exists before trim operation, therefore the user need the restriction preservation, some option to that toot to toolwidget to preserve or not preserve already existing restrictions.

[kisolre]

IMHO that would only work if the trimmed part is automatically replaced with the same geometry but construction mode and necessary constraints are applied. Which in most cases will overcomplicate the sketch ?!?