Add curves does not work on lines, on iPad, Mac and Windows, [solved]

[pruus]

I did draw a few lines, then I did want to add them to one curve. The curves disappeared when adding. Than I did the same with some rectangles, this works fine. But the lines disappear when adding to each other. See enclosed video. And I added the file. Strange…..

 

add-curves.afdesign

[stokerg]

3 hours ago, pruus said:

The curves disappeared when adding

Unless I'm mistaken, I believe this is due to the curves still being seen as 'open' and not a closed shape, like the rectangles are.  A quick way around this, would be to use Expand Stroke on the 2 lines and then use Add and you'll see everything stays in place.

[GarryP]

An alternative, in this particular case, since the curves have the same formatting applied, would be to use menu “Layer → Geometry → Merge Curves” instead.

[pruus]

How can they disappear? It were two separate lines. Merge curves works. Thanks @GarryP

[Old Bruce]

2 minutes ago, pruus said:

How can they disappear? ...

I would think that what is happening is the "Areas" of the open curves are being added. Being as there is zero area being added to zero area...

[pruus]

@Old Brucesounds logic. Thanks.🙏 

[v_kyr]

2 hours ago, pruus said:

How can they disappear? It were two separate lines.

AFAI recall from v1, objs (curves) with only/just strokes often didn't work, only filled curves (areas).

[HCl]

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[R C-R]

2 hours ago, Return said:

Perhaps the merge curves and separate curves buttons should be added to the standard/default toolbar options and make add unavailable when using just open curves.

Since filled open curves can have an area & thus can be boolean added I think add should be greyed out only when there is no area to add.

Edit: Even better, maybe consider any curve's stroke to enclose an area equal to its width so boolean add always will add the two curves together?

[HCl]

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[R C-R]

21 minutes ago, Return said:

I think Serif stepped away from that method where the path runs back on itself to create in essence a closed shape.

This would create problems when editing nodes on top of each other and maybe break other tools like corner, contour, shape builder and the knife tool.

What problems/issues would there be if the area of a stroke's width was included only when using boolean add?

Besides, an open curve does not create a closed shape even if it crosses itself, so I'm not sure what you mean about that.

[GarryP]

Interestingly, and according to the Help, some Geometry functions sometimes give results with open curves and some don’t.

For example, you can ‘split’ a closed curve/shape by drawing open curves across it and then using Divide (and using Alt+Divide has a different, but interesting, result).

Having said that though, I would expect that Adding two open curves would result in nothing because, as has been stated above, there’s ‘nothing’ to ‘add together’ with one-dimensional things. It could be argued, and pushing it a bit, that I might imagine that I should get a number of zero-dimensional points remaining where the curves intersect but the software doesn’t have a Point layer type, and I’m quite glad of that in a way.

Note: I think the title of this thread may show where part of the confusion comes from where it says that “Add curves does not work...”, and that’s because the functionality is more like “Geometry/Boolean Add” rather than “Add Curves”, whereas the functionality “Merge Curves” does what it says on the tin.

Edited July 25, 2023 by GarryP
Added note.

[HCl]

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[R C-R]

5 hours ago, Return said:

See my video about what I mean as it is in XaraDesignerPro+

I do not understand what that has to do with boolean add including the width of strokes as part of the shape.

[pruus]

I have now an solution, the steps for lines:

• select both lines
• choose expand stroke
• than add both lines