Sketcher - How do I edit arc start angle?

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sjb
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Joined: Thu Apr 27, 2017 10:40 am

Sketcher - How do I edit arc start angle?

Post by sjb »

I'm wanting to add a 90 degree corner to a line on a Sketch. (The Sketch is that shown in https://wiki.freecadweb.org/Part_and_PartDesign).

Using Draft, I can edit arc parameters. Using Sketcher though, I see no way to type in an arc's start angle - it seems to rely on precise mouse usage to define it.

If it is not possible edit the start angle of a Sketcher arc, maybe I can use the tangent constaint somehow in this case?
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Sketcher - How do I type in start angle for arc.png
Sketcher - How do I type in start angle for arc.png (30.56 KiB) Viewed 772 times
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NewJoker
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Re: Sketcher - How do I edit arc start angle?

Post by NewJoker »

In the Sketcher you draw objects first and then dimension them. This might be changed in the near future by paddle's tool settings widget but for now you have to use dimension constraints after creating the geometry. In this case, use the Sketcher ConstrainAngle tool to set the span of an arc.
sjb
Posts: 60
Joined: Thu Apr 27, 2017 10:40 am

Re: Sketcher - How do I edit arc start angle?

Post by sjb »

Hi

I have done that - the angle is 90 degrees. However, the start angle is not 0 degrees, so the 90 degrees spans (say) 10 degrees to 100 degrees
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papyblaise
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Re: Sketcher - How do I edit arc start angle?

Post by papyblaise »

there are several ways
1- make a rectangle with the rounded corners (see the tool by unrolling the button of the rectangles)
2- use the tool to make the corner radius, it will make the tangent connection
3- make construction lines and start the arc tangent to one line and stop tangent to the other line 4- make the rectangular corner Pad then "Fillet"
4- Faire une polyligne avec un rayon au bout du segment tracer (touche M) il sera tangent automatiquement
maybe there's something else i'm not thinking about right now
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Willem
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Re: Sketcher - How do I edit arc start angle?

Post by Willem »

You need a fillet that preserves constraints
Schermafdruk van 2022-09-29 16-33-51_copy.png
Schermafdruk van 2022-09-29 16-33-51_copy.png (58.2 KiB) Viewed 734 times
sjb
Posts: 60
Joined: Thu Apr 27, 2017 10:40 am

Re: Sketcher - How do I edit arc start angle?

Post by sjb »

Many thanks for the replies. I think the 'constrained fillet' method might be the most direct one here.

PS: I wondered about about how the 'unconstrained' vs 'constrained' choice affects things exactly...The wiki page does not mention the 'constrained' option. I did experiment though, and it seems to make sense.
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Sketcher Fillet Types.png
Sketcher Fillet Types.png (40.88 KiB) Viewed 694 times
sjb
Posts: 60
Joined: Thu Apr 27, 2017 10:40 am

Re: Sketcher - How do I edit arc start angle?

Post by sjb »

Useful links.

I have now looked more carefully at 'polyline' (also suggested by papyblaise "4- Faire une polyligne..."), and that might be the fastest way to create this sketch "from scratch".

Is that how you would draw the example sketch? i.e. Create a closed polyline (including the 90 dgree curves), then add the constraints?
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