Proper way to convert lines to fillable shape?

[Acorn]

Please don't get me wrong: I appreciate knowing each of these methods. But none of them give the simple result of a fillable shape with the lines preserved.
In testing the methods, either the lines were absorbed into the shape ... or I ended up with two shapes, one with the lines and one fillable.

Sorry to disagree but my approach left you with your lines and a filled shape. The cusps are simply the lines (necessarily) folded back on themselves so it is arguable if the lines are not "preserved" as they do not form part of the changing of the shape body from this point.
As I can alter the line thickness and colour, I don't believe the lines are "absorbed" either.
I saw this to be the canonical form of what you needed.

@handrawn As you didn't include my approach to be a "grouped" one, is my shape one shape? I think it is.
Further, it is editable, though you have to manipulate the cusps separately.

Acorn

[theinonen]

But does it really matter if the object is really a single shape or grouped one, if it will act just the same way in use when it comes to changing line width, or the colour of the fill or line?

[handrawn]

Hi acorn

actually I stand corrected - you can do it, if you simply combine the lines to shape using ctrl+1 [add shapes] - and not 'convert line to shape' or convert to editable shapes' first - then all you need to do is break shapes and change fill colour

and on that basis you may well be right, although i have difficulty following your method...

[post's up example and goes away to do something useful... rather than overthink things ]

EDIT - having actually read Frank's tip, this is exactly what he suggests - so it serves me right for speed reading it the first time - nice one Frank

[handrawn]

But does it really matter if the object is really a single shape or grouped one, if it will act just the same way in use when it comes to changing line width, or the colour of the fill or line?

quite possibly if you want to use it with transparency or in another boolean operation..... for example

and editing anything that is grouped is always more trouble than it is worth if it can be avoided

[Acorn]

I put up my approach as XWD9P doesn't have Arrange > Break Shapes.
The end result is the same as BF's, save the inner shape is already deleted.

Cusped Shape.web

Acorn

[handrawn]

thanks for the steps simple when you know how and a good method where there is no break function

[Contours]

Thanks for all of the above. The resulting steps are really quite simple ... but not intuitive in any way that I'm aware of.

So, as a clarification for anyone following this discussion, I'm attaching a summary of the four steps using my original figure.

I'll also mention that (for reasons I can't begin to fathom) these steps do not work if the lines happen to first be grouped. So, be sure to start with a set (not group) of lines that intersect.

[handrawn]

you know the minute I re-read Frank's tip I had that 'doh - I knew that' feeling - that's where trying to work things out logically gets you if the logic ain't right

but ever the glutton for punishment I'll try a take two..

what looks like a line can actually be a shape that just happens to be in the shape of a line - in a vector program these are two different beasts

when you come to join them you have to let the program know whether you want a box shape with a fill, or a box where the shape is actually the 'outlines' of the box, or something else

this, like everything else in vector is determined mathematically, and the branch that deals with intersection and subtraction is called boolean logic - and logic there will be in there at that level

I'm now going to quit whilst I'm still ahead