Does it possible to have a sort of Offset like this ? Variable Offset (?)
Blue curve is Source
Red Segments are distances given
Orange curve is "Special Offset" result

Using Orient / Line-Line option Stretch gives not entierely a good result

and mixing Uniform and stetch don't work too!

Hi Pilou, you could try using Sweep - select all your lines for the profiles, and then run Construct > Sweep and then pick the closed curve as the sweep rail.

But it may have some difficulty dealing with the tightly bent and wiggly areas, anything similar to offset tends to magnify wiggles and have difficulty when the path bends at a tighter radius than the offset amount.

- Michael

No Sweep create some crossing curves following the "angle" of the curve profil! :(

Hi Pilou,

> No Sweep create some crossing curves following the "angle" of the curve profil! :(

Sorry I don't understand what that means. Can you post an example file?

It may be difficult to get any type of offset on that kind of curve because of the tight bends and wiggly areas in it.

- Michael

So here :)

Of course I can redraw over the line-line result for have cool jonctions but...



http://moiscript.weebly.com/uploads/3/9/3/8/3938813/sweep.3dm

Hi Pilou, what you need to do is use this one you show here:



Extract the inner edge curve by selecting it and doing a Copy/Paste (Ctrl+C/Ctrl+V), then use Edit > Trim to cut the areas of self intersection away.

The regular offset command does this kind of trimming built in to it, but when you use sweep to generate the variable offset you will need to do the trimming yourself as an additional step.

- Michael

I've attached here a version where I've done that next cleanup step, is this the result you were trying to make? :



The cleanup steps are:

1. Select the inside edge with the self-crossing loops in it.

2. Duplicate it as a separate curve object by running Copy / Paste (Ctrl+C/Ctrl+V). You can now delete the sweep surface since you won't need it anymore.

3. Select the inside curve and then run Edit > Trim. At the prompt to select cutting objects, just push "Done" or right-click in a viewport to indicate that the curve will cut against itself at self-intersection locations. Select the excess areas (using window selection from left to right that only captures things entirely in the window is useful for this), and then push "Done" or right-click in the viewport to finish the Trim and then it's done.

- Michael

Edit: Said the wrong way (right to left instead of left to right) originally.

Cool trick
Just now find another one for kill the outcurves easily and speedly! :)

Edit Sorry :crossing post I have don't seen the another trick of selection!

But how do you select the outline in one pass ?
Seems i must make multiple precise clicks selection like the first?

Hi Pilou,

> Just now find another one for kill the outcurves easily and speedly! :)
>
> Edit Sorry :crossing post I have don't seen the another trick of selection!

Yes, window selections help to make the selection step go more quickly. I just timed myself and it only took me 12 seconds to finish the trim cleanup step. The end result should be the type of variable offset curve that you're looking for.

Also in some cases it may be easier to keep the pieces to keep in the Trim command rather than picking the pieces to remove - to do that set the option for Mode = "Keep" in the Trim options and then click in the middle area of the large pieces that you want to keep.

- Michael

Another crossing post
See my anime above :)
You make many selections right to left ?
And yes the result is the result wanted!

There is not an "internal" selection loop ?
(from a left extremety of a "good" first segment at each intersection I go on the left for example ;)

Hi Pilou,

> But how do you select the outline in one pass ?
> seems i must make multiple precise clicks selection?

Yes you make one selection per corner area, but going starting from the left and going to the right. When you go in that direction it only captures things that are totally contained inside the window. The other direction (starting right and going towards the left) which you are showing above will capture anything that crosses the box at all, which you don't want in this particular case.

Here is a demonstration, especially notice the on which side I start each window, and see how quickly it goes:




- Michael

Yes That is I have under stood! A multiple selection! :)

What do think of my another crossing post of the pseudo code of an internal loop selection?

Hi Pilou,

> Another crossing post
> See my anime above :)
> You make many selections right to left ?
> And yes the result is the result wanted!

Sorry it looks like I said the wrong way above (I will edit it) - you want to start on the left and go towards the right for the "strictly contained inside" type of window selection.



> There is not an "internal" selection loop ? (at each intersection I go on the left for example ;)

Sorry no there isn't any automatic way to do the loop selection, you will need to do the 12 seconds of selecting things to get the final result.

- Michael

OK! That will be maybe for the V5! ;)

In any case very cool trick!

Hi Pilou,

> What do think of my another crossing post of the pseudo code of an internal loop selection?

Maybe someday, but as you can see in my example video it really goes quite quickly already - it would take me a lot longer time than 12 seconds to make a special internal loop selection mechanism. So for now just doing this type of selection should get the job done quite easily already.

- Michael

<< it would take me a lot longer time than 12 seconds to make a special internal loop selection mechanism.
Sure! :)
But possible in theory without time limit?

PS I made the "selection" in less than 6 seconds! ;)

Hi Pilou,

> But possible in theory without time limit?

Sure! But it's hard to come by that unlimited time in practice though! ;)

And actually it could be somewhat difficult to implement, selection code could probably separate things into different groups but it might have some difficulty deciding which of the groups are meant to be kept and which are meant to be discarded. The Offset command is able to do that better because it does extra work to keep track of where pieces originated from.

But at any rate, it would take me far longer to implement it than the amount of time that it would save you.

- Michael

In case of result of points angle jonction are too "hard" no possibility to automate this ?
Trim at equal distance then "Blend" them

Hi Pilou,

> In case of result of points angle jonction are too "hard" no possibility to automate this ?
> Trim at equal distance then "Blend" them

Try using the Fillet tool on the curve for rounding off the sharp corners.

First join the curve pieces together so you've got one long closed curve. Then select it and run Construct > Fillet. The Fillet command will show points at each sharp corner and will prompt you to select which corners you want to round off. You can just right-click or push "Done" to target all of them.

Then enter in your fillet radius, and you can choose whether you want a circular shape or a blend shape for the connecting pieces.

That will round off all the sharp corners in one step.

- Michael