Is it possible to produce an arc shape with given start and sweep angle? (Using Sketch 3.0 by bohemian.coding)
Just updated this: brand new Segmented Circle 2.0 Sketch plugin.
Automatically create precise segmented circular graphics for diagrams, instrumentation and analytics. Huge update adds multi value pie chart styles, tick mark circles and perfectly dashed arcs.
You could fake it by using the Layer > Vector > Rotate Copies. Simply choose a rectangle shape and then create any number of copies. The more copies you create, the smoother the arc will be.
You can also create Two Circles, subtract them, and then subtract a rectangle in half:
Finally, you could draw it with the pen tool (though you'd lose some accuracy in the process.
Unfortunately, you won't be able to adjust the angle or the sweep. But if you manipulate shapes on top of shapes and use the Pathfinder or Transform tools, you should be able to achieve your desired effect.
There is now a great sketch plugin for this:
"Create circles as areas or lines with a custom number of points/segments" https://github.com/design4use/gb-sketch-segmentcircle
Another way is to draw a circle, double click on it to edit it (there will be 4 little dots equally spread over the circle), and click where you wish to end the shape so you have another small dot appearing there. Use the scissors to remove any unwanted part, the part to remove will change its shape when you mouse over it. You can finish you arc shape with different ending such as rounded, this is done in the border section, click on the related COG to show this section.
While you can fake an arc in Sketch, it does not appear to be possible to make an actual "arc" as described by the svg standards: https://developer.mozilla.org/en-US/docs/Web/SVG/Tutorial/Paths#Arcs
This is because the vector tool does exclusively Bezier curves (https://developer.mozilla.org/en-US/docs/Web/SVG/Tutorial/Paths#Bezier_Curves) or straight lines from both sides of a vector.
If you ever feel the need to be able to make an arc for real, it may be best to just write your svg code by hand. I've had to do it more than a few times.