Affinity Designer v1 Ipad - Drawing A Second Curved Line Which Is 3 Cm Far From The First One

[Mainecoon364]

Let’s say I drew the Black Line.

 

Now I want to draw the Red Line.

 

As you see the distance between the Black Line and the Red Line is 3 cm.

 

How can I draw the Red Line?

[walt.farrell]

If you want it 3 cm apart everywhere, it sounds like you want a duplicate of the black line. So, simply duplicate it and change its color. Then: 

1. Select the black one with the Move Tool, and note its Y position in the Transform panel. Call this P.
2. Select the red one with the Move Tool, and set its Y position in the Transform panel to P+3 cm (calculated manually).

[Optische Ausrichtung]

If I understand the problem correctly, the questioner is looking for an "expand stroke function" that only works on one side of the curve. Perhaps the desired result can be achieved with the function and a little reworking. Of course, there are a few pitfalls to consider: https://en.wikipedia.org/wiki/Parallel_curve

[NotMyFault]

11 hours ago, walt.farrell said:

If you want it 3 cm apart everywhere, it sounds like you want a duplicate of the black line. So, simply duplicate it and change its color. Then: 

1. Select the black one with the Move Tool, and note its Y position in the Transform panel. Call this P.
2. Select the red one with the Move Tool, and set its Y position in the Transform panel to P+3 cm (calculated manually).

This method does work only for straight lines, but not for general curves, take a circle as example. The correct answer would be a circle with 3cm larger / smaller diameter, not a circle just moved by 3 cm.

In Affinity Designer you could use the contour tool for a closed curve. 
 

If you have an open curve, you need to close it temporary and mask out the unwanted part later.

[NotMyFault]

[walt.farrell]

12 hours ago, NotMyFault said:

This method does work only for straight lines, but not for general curves

I did it with a curve similar to the one in the first post before replying. 

EDIT: But even that was only approximate, and there are definitely cases where it would need an X translation as well as the Y translation. So thanks for pointing that out, @NotMyFault.

 

[Mainecoon364]

@Optische Ausrichtung

 

Yes you understand It correctly.

 

Is it possible to do this?

 

 

[walt.farrell]

1 hour ago, Mainecoon364 said:

@Optische Ausrichtung

 

Yes you understand It correctly.

 

Is it possible to do this?

 

 

Please explain more, as I do not see how that is an Expand Stroke function, which would give you 1 line not 2 as I understand it. You asked for 2 curves, not one wider curve.

However, for what you showed, and considering the flaws that @NotMyFault pointed out with my approach, you might also consider something like this:

1. Duplicate the curve, and change the duplicate's color to red.
2. Change the black curve's stroke width to 6 cm (twice what you want).
3. Move the red curve so it aligns with the lower edge of the black curve, which will be 3 cm from the original line's center.
4. Change the black curve's stroke width back to its original value.

[Optische Ausrichtung]

4 hours ago, Mainecoon364 said:

Is it possible to do this?

Yes.

1. The black curve is present.
2. Duplicate this curve and set a contour width of 6 cm (yellow in the image). 
3. Select the "Expand Stroke" function.
4. Delete the points marked blue in the image. 
5. The result is a closed curve that can be opened with the Break Curve tool, adding a point if necessary.
   (In the image, this is approximately the light gray part.) Delete the superfluous points. 
6. The result is the red curve. 

I hope you get it to work on the iPad.

 

[Mainecoon364]

Where is Expand Stroke function on Ipad v1 version?

[NotMyFault]

https://affinity.help/designeripad/en-US.lproj/pages/CurvesShapes/expandStroke.html
 

Edit Menu->Expand Stroke