AD2.1.1: The Contour tool sometimes produces erroneous outlines.

[purplie]

Summary: The Contour tool sometimes produces erroneous outlines.  

Application:  Affinity Designer 2.1.1

OS: MacOS 13.5

Reproducible: Yes

Notes:   The attached screenshot & sample file show, on the top row, three polygons; on the bottom row, the result of applying the Contour tool.

The bug seems to occur frequently when two nodes are very close together (third example), or when a control point is close to the next node (first and second examples).

 

Untitled.afdesign

[Old Bruce]

The top three are formed in a very odd manner. Two or them have sharp nodes with handles extending way out and the parallelogram has an extraneous node on the upper Right. I put a bit of a curve in the two squares so you could see what I mean.

  

[Hangman]

Hi @purplie,

This happens, as @Old Bruce highlights when you have node handles on Sharp nodes. The solution for the two rectangles is to zoom in and Alt (Option) click the end of the Node handles to remove them and on the trapezoid delete the extraneous node (as @Old Bruce already mentioned)...

[purplie]

Yes, those examples were hand-made, and were deliberately simple, for the bug report.  The manual workaround is feasible for those.

But let me provide some naturally-occurring examples.

• Attempting to thicken the strokes of text in a complicated font.  See 'example-2.afdesign', attached.
• Attempting to apply a contour (negative contour, in this case) to a spherical Voronoi diagram.  See 'example-3.afdesign', attached.  The bug occurs where some vertices are close together.

example-2.afdesign example-3.afdesign

[Hangman]

Hi @purplie,

7 hours ago, purplie said:

Attempting to thicken the strokes of text in a complicated font.  See 'example-2.afdesign', attached.

I honestly don't know whether this would be considered a bug or expected behaviour, I think someone from the Serif team would need to comment but certainly with the text example there are so many nodes created when that particular font is converted to curves, it really doesn't surprise me that you are going to see some anomalies but they are pretty straightforward to correct.

It may be that the code behind how the contour tool works can be tweaked or improved I really don't know but on very complex shapes I think you perhaps have to budget for a little cleaning up in the same way you would if you were to use an auto-trace tool to convert a raster graphic to a vector graphic.

Blackmoor Text Cleanup

 

With the sphere example, this appears to happen when you have two nodes in close proximity with a small angle between them, a bug or expected behaviour I don't know but again, very easy to rectify... I'm sure someone from the Serif team will be able to provide better feedback regarding this and what to expect with regards to your two examples.

Sphere Cleanup

[purplie]

I appreciate what you're saying, but when I have 1000 small puzzle-piece shapes to be laser-cut, inspecting every one of them individually to check whether the outline is erroneous isn't quite the workflow I'm hoping for.  It's not always easy to tell at a glance.

I like Affinity Designer, and I really hope the "expectation" isn't that I use a different editor for this task. 🙁

I quite understand that if other people aren't complaining about it, then it's not a high-priority bug.  But I hope it stays in the list.

Thanks!