Drawing curves next to each other

[Mr Flow]

Hi,

I want to draw a curve that follows precisely another existing curve. In my picture I want to draw a curve that is adjacent to the existing curve. Basically an existing curve would act magnetic to a new curve. Is that possible?

Thanks
Mr Flow

 

[GarryP]

Welcome to the forums @Mr Flow

If you have Designer then the Contour Tool might be useful.
Or you might be able to use the Appearance Panel.
And there could be various other things you could use depending on what it is that you want to do.
Can you give us more details about what you want to do, specifically what you mean by “adjacent” and “magnetic”?
Any visual aids you can supply would probably help.

Also, which Affinity application(s) do you have access to?

[Pšenda]

Or mean Autotrace function? 

[Hangman]

It all depends what you are trying to do but these options on the context toolbar 'may' help...

[thomaso]

Not directly related but worth to mention is a slightly hidden feature of auto-adjusting curves, respectively auto-copying node handles. Just drag & hold a second …

[Mr Flow]

Hello everyone,

first of all I want to thank all of you for the warm welcoming and the many replies. 

I was a bit in a hurry earlier so I will try to specify my project. I have that picture of an owl (it's a logo actually) and the part I scribbled green needs to be coloured. So I need a shape that fits exactly in there.

Right now I think thomaso's idea helps me the most, but again I was very unprecise about my project in the beginning.

 

Edited June 15, 2022 by Mr Flow

[GarryP]

The quickest way to do what you want is probably to draw a filled shape which covers the area you want to fill and then put it underneath the original artwork – a bit like how they used to draw cartoons with the filled bits drawn on a separate sheet of acetate under an outline sheet, if you know what I mean.
There will be other ways.
You will need to decide what you want to do where there is a gap, e.g. to the left of the owl, or at the top of its head.

[Pšenda]

4 hours ago, Mr Flow said:

I want to draw a curve that follows precisely another existing curve.

Due to the line thickness used, no "precise" work is required - just draw the marked area and hide it behind the logo.

[Mr Flow]

The idea of layering unprecise shapes underneath the owl was my first idea too. But I thought there might be a better way.

Anyway thank you very much. 😀

Is that auto-adjusting curve feature mentioned anywhere? That is completely new for me.

[GarryP]

The “auto-adjusting curve” (noted by thomaso above) might be mentioned in the Help but I don’t know what it will be called.
Even if it is mentioned in the Help it’s not likely to be documented extensively so it might be best just to experiment and see what it does in different circumstances.

[thomaso]

1 hour ago, Mr Flow said:

Right now I think thomaso's idea helps me the most

Note that the number of nodes in existing & new curve do matter and ideally would match. So, depending on the nodes in your existing drawing this workflow can be far less efficient than just drawing manually, as mentioned by GarryP and Psenda. In particular for vectorized raster images which may contain a lot more nodes than required (... as possibly in your "owl" illustration).

[iconoclast]

Probably I didn't really understand the topic, but if you want to create a curve that exactly follows an existing curve, why don't you duplicate the curve?

If it's all about the inner shape to be filled, you could select the Nodes of the duplicate that don't belong to this inner (negative) curve shape and delete them. As a result you will get a curve object of this inner shape that can be filled as you want.

Edit: In case of your example above this will not work without some additional steps, because the inner area you want to fill is not a closed area. So you should open the Nodes of the duplicate at the points the curve needs to be closed and close it there manually by using the Pen Tool.

[Mr Flow]

I tried opening the curves in the very beginning but ended up with large black "things". Now I tried again, paying more attention to the layers panel and recognised that, if you open a curve on at two points, Designer somewhat "closes" them and fills the area with a colour. So I think I have a pretty good workflow now.

Learned much today 😀

[walt.farrell]

20 minutes ago, Mr Flow said:

if you open a curve on at two points, Designer somewhat "closes" them and fills the area with a colour.

If you have told it to use a Fill, and if the curve is not a straight line, then yes, you would get that. If that's problem, don't specify the Fill.

[iconoclast]

22 minutes ago, Mr Flow said:

I tried opening the curves in the very beginning but ended up with large black "things". Now I tried again, paying more attention to the layers panel and recognised that, if you open a curve on at two points, Designer somewhat "closes" them and fills the area with a colour. So I think I have a pretty good workflow now.

Learned much today 😀

These "large black things" you're talking about are probably the fill colour of the initial curve object that is still there if you open the curve at the certain nodes. I know that is irritating. In that case deactivate the fill of the shape and give the curve path a thin coloured stroke.