Path tracing without thickness

[kronos]

When path tracing image,

Inkscape creates path with some thickness based on the image.

How to path traced it without thickness?
As if you would create spiro path.

[brynn]

Welcome to the forum!

I think you might be asking for centerline trace.  Although while it will give you a thin path, I don't think you'll like what happens where the lines intersect.  If you want to try, you'll need to use a different trace engine, because Inkscape's Trace Bitmap doesn't offer it.  You could try:  http://www.roitsystems.com/cgi-bin/autotrace/tracer.pl

I can't think of any easy way to use that trace result, and change it into a single, closed path.  Because you may have noticed what happens when you trace an image.  Select that result with the Node tool.  Then you can see that it's not just a thick or wide, single path.  It's a filled, compound path.

There might be a way to use Trace Bitmap to make that image look thinner.  But it will never be a single closed path.  It will always be a filled object.

Or you could probably use Path Inset on that trace result above.  That will make it thinner too.  But again, it won't be a single path.  It will be the same filled object, except thinner.

Or you might be able to use that drawing as a guide, to draw your own spiro spline.  You can trace over it (zoom in so it's very large, for best results).  Change the color, so you can see it on top of the black one, and just tweak the nodes with the Node tool, until it matches very well.

[Lazur]

Instead of tracing, why not plotting it with the parametric curves extension? Shouldn't be that hard altering a lemniscate shape.
(for example)

[kronos]

Welcome to the forum!

I think you might be asking for centerline trace.  Although while it will give you a thin path, I don't think you'll like what happens where the lines intersect.  If you want to try, you'll need to use a different trace engine, because Inkscape's Trace Bitmap doesn't offer it.  You could try:  http://www.roitsystems.com/cgi-bin/autotrace/tracer.pl

Link does not work.
Yes, I'm looking for the thin path. The thinest.

I'm not that good tracing it manually so I always use Trace Bitmap when I can.

Path Inset does some good result. Better than just traced. Thanks.  How to control how much of the inset I want?

Instead of tracing, why not plotting it with the parametric curves extension? Shouldn't be that hard altering a lemniscate shape.
(for example)

How to input parametric curve ?

[brynn]

Oh wow, I wonder where that site went?  I'll have to research.  Otherwise, I think Vector Magic has an autotracer.  But I don't have a direct link.

For parametric curves, you have to know the specific formula.  I have no idea how to find it out.

[kronos]

Is there some inset parameter or percentage how much does path get insetted?

[brynn]

Well, the way back machine doesn't have it archived - something about a robot on the page or something.  But it's still found in 2 pages of internet search.  So it seems like it hasn't disappeared that long ago.

Hhm, but the whole domain is gone!

I don't know what happened.  I've known about it for almost 10 years.  I just don't know......

Yes, for Path Inset, every time you click Inset, it moves the path by 2 pixels (unless you've changed it in Preferences).  When you use it on that image, you'll notice that the inside path moves towards the outside by 2 px, and the outside line moves inwards, at the same time.  I would guess you won't have enough room for more than a couple of steps.

[brynn]

It's not necessarily a precise way to do it.  I would say hand tracing with spiro spline would be the most precise.

If this is a one time project, I wouldn't mind trying to make it for you.

Or maybe Lazur knows the right formula for parametric curves?

[kronos]

It's not necessarily a precise way to do it.  I would say hand tracing with spiro spline would be the most precise.

If this is a one time project, I wouldn't mind trying to make it for you.

Or maybe Lazur knows the right formula for parametric curves?

Oh, you don't have to. Thanks. I'm fine with insetted path.
But I would like to learn how to do with parametric formula lemniscate and lissajous curves.

[Lazur]

But I would like to learn how to do with parametric formula lemniscate and lissajous curves.

Check this svg:



Plotted curves are:
Bernoulli leminiscates, quadrifoliums and Lissajous curves.
Wikipedia lists a few more.

[kronos]

Thanks. How did you set parametric equations in inkscape?

Is there a tutorial on this ?

[Lazur]

If you open the svg with inkscape, all the settings are present.
You can copy-paste the values to the extension to plot the exact same paths -extension>render>parametric curves.
(Only modification added manually was connecting the start-end nodes to the plotted paths.)

Click on the image, download the svg and open it in inkscape. Cannot break it down more.

[kronos]

If you open the svg with inkscape, all the settings are present.
You can copy-paste the values to the extension to plot the exact same paths -extension>render>parametric curves.
(Only modification added manually was connecting the start-end nodes to the plotted paths.)

Click on the image, download the svg and open it in inkscape. Cannot break it down more.

Thank you.