Composite curves?

[Roqoco]

When I use the boolean add operation to add to a closed curve it can create areas inside that are themselves closed curves or at least they appear to be. That is the functionality that I want (I am creating a map and have made a shape that is intended to add "lakes" cut into the landscape by glacial action). But, what is confusing me is that these enclosed curves are not treated as separate objects, but seem to be bundled up with the original curve, so that when I select them, both the original curve and the enclosed curve are selected. I'd like to get to a structure where the enclosed "lake" curves are separate and nested under the original curve in the layer hierarchy. Incidentally, this curve nesting also seems to cause problems when importing or exporting shapes in SVG format.     

[loukash]

Compound paths?
https://affinity.help/designer/English.lproj/pages/ObjectControl/compound.html

[Roqoco]

Thanks! That wasn't quite it, but reading it immediately lead me to notice that the shape was marked "curves" plural. I then pressed "divide" on the toolbar and everything magically (!?) split apart as I wanted. Really handy.  

[loukash]

13 minutes ago, Roqoco said:

I then pressed "divide" on the toolbar and everything magically (!?) split apart as I wanted.

Hm, perhaps it doesn't necessarily apply to this very task of yours here, but you should be also aware that Affinity's Divide – and other boolean operations for that matter – won't always do what you'd want or what you'd expect they would do after you have worked with other vector apps before:

And those are definitely bugs, not "features".

[Roqoco]

Well this was certainly functionality that I didn't expect!?

As to your jigsaw puzzle splitting, was playing around with that recently and found that you can do it if, after drawing the lines through the shape, you go "Expand stroke" on each of them to get rid of the fills.Then set line to a minimal stroke size and press divide. Mostly that works fine when I do it. And it does look in your example result that the fill is what is interfering with the operation.

[loukash]

46 minutes ago, Roqoco said:

set line to a minimal stroke size and press divide

BRILLIANT! Thanks!

Works pretty good with stroke width set to 0.001 pt. Then you won't see the gap between the divided objects until zooming in like 10000 % or so, at least on a non-retina display, and each object will still nicely snap to the others.

Going for more decimal places – up to 0.000001 – will cause the ultrathin stroke expansion to add too many unnecessary nodes, that being yet another known bug.

1 hour ago, Roqoco said:

it does look in your example result that the fill is what is interfering with the operation.

The problem is that open paths auto-close on boolean operations. That's the bug. A fill or no fill doesn't make a difference.

Which reminds me, what I in fact tried back then was to duplicate each open path and close it "in place". That didn't work well, however, as I ended up with hundreds of nodes and subpaths and other "boolean junk". So actually I've almost "been there done that" before, except for the final step to "expand stroke".