measurement of the length of a curve

[Jutta]

hi there,

how  to get the exact length of a curve 

or the circumference of a circle

in affinity designer?

[dutchshader]

As far as i know this is not possible in designer.

[Alfred]

11 minutes ago, dutchshader said:

As far as i know this is not possible in designer.

 

No, it isn't possible yet. Perimeter and area measurements have been requested a few times, but at the moment we have to use external tools.

 

Windows users can export a drawing to PDF and use the measurement tools in PDF-XChange Viewer to determine the length of any curve (or the area bounded by any closed curve).

 

[R C-R]

5 hours ago, dutchshader said:

As far as i know this is not possible in designer.

For the circumference of a circle you could do this (inelegantly) as follows:

1. Select the circle & note its width or height in the Transform panel.

2. Using (for example) the Pen Tool in Line mode, draw a horizontal line. (Use snapping to make sure it is perfectly horizontal.)

3. In the Transform panel use the expression pi*<width or height of the circle> to change the width of the line.

4. This width is the circumference of the circle.

 

Of course, this is of very little practical value but I did use it once to check the movement of a wheel along a road. In the attached wheel roll test.afdesign, each ellipse is 200 x 200 px, so the 'baseline' road is 628.32 px. Moving copies of the ellipse by 628.32/4 horizontal increments & rotating them by -90° increments gave me the template I needed for the project.

[Alfred]

5 minutes ago, R C-R said:

In the attached wheel roll test.afdesign, each ellipse is 200 x 200 px, so the 'baseline' road is 628.32 px.

 

Easy as pi!

 

[firstdefence]

Would be cool to have this feature:

 

[johnnyfive]

Not so easy for complex curves... still hopeful for an update.

[mahboud]

It would be really nice if I could get the measurement of a complex curve, by tracing it, and then locking that new curve and unrolling it into a straight line. Where this is useful is if you are creating something on a laser cutter and which to add a perpendicular element to the edge. For example a box where the top and bottom are an irregular oval shape, and you want to make a wall for that box. You'll need to know the circumference of the oval in order to start creating the wall.

[BradyE]

Any Update on this feature? I'm planning a couple of signs using EL wire and this would be a great help.

[Pšenda]

2 minutes ago, BradyE said:

Any Update on this feature? I'm planning a couple of signs using EL wire and this would be a great help.

No.

[John Rostron]

On 6/7/2018 at 9:04 PM, johnnyfive said:

Not so easy for complex curves...

Easier than you might think. If you export a curve as svg, you can see that it is made up of segments which might be straight lines of Bezier curves.  These can be read by suitable software and used to calculate the length of each segment and thus the length of the curve.

I wrote a PHP script which reads an SVG curve and calculates the length, but I don't think that is engendered any interest. However, if I can do that, I'm sure an experienced developer could do it. It is just a matter of priorities.

You really should be posting such requests in Feedback forums, by adding your support to existing threads asking for this, such as this one.

John

[R C-R]

6 hours ago, John Rostron said:

If you export a curve as svg, you can see that it is made up of segments which might be straight lines of Bezier curves.

What if the segments are not straight?

[Old Bruce]

11 minutes ago, R C-R said:

What if the segments are not straight?

I read "lines of Bezier curves" as "lines or Bezier curves". I think it is just a typo.

[John Rostron]

16 hours ago, Old Bruce said:

I read "lines of Bezier curves" as "lines or Bezier curves". I think it is just a typo.

@R C-R, @Old Bruce

My mistake. It was a typo. The SVG path directive allows you to specify a mix of straight lines, Quadratic Bezier Curves, Cubic Bezier Curves or Arcs within one path.

John

[PixelPest]

For me it´s Inkscape:

[Zmip]

On 9/17/2021 at 5:54 PM, R C-R said:

What if the segments are not straight?

The segments are always straight. That's the way the formula works (Bézier or DeCasteljau). What you see as a curve, is actually a large number of 100% straight line segments. Would be really, really simple to implement.

[Kal]

On 9/18/2021 at 11:32 PM, PixelPest said:

For me it´s Inkscape

Thanks for that, very useful! Requires the Measure Path extension.