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Raskolnikov

Turning an irregular shape into regular

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It's a great trick that one!! thanks... Although would it better to have that possibility while using the node tool.

Now it lefts to me to know how to make the lenght of those arrows the same. Would be useful to have any magnitude measure while use them. To make them symmetrical on 2 (elipse) or 4 sides (circle).

Captura 2017-09-09 a las 17.29.15.png

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Hi Raskolnikov,
What owenr is doing is creating/extending new handles for the selected node and aligning them, not editing/aligning existing ones with the Node tool (which will be possible in a future update as i said). Currently it's also not possible to align handles between them - you have to use guides for that. Not sure if this is being considered for the update.

 

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19 minutes ago, MEB said:

What owenr is doing is creating/extending new handles for the selected node and aligning them, not editing/aligning existing ones (which will be possible in a future update as i said).

 

Please could you explain that in a little more detail, Miguel? I don't think it's possible to create new handles for a selected node: as I understand it, every node has exactly two handles, although at least one of them will be invisible if it's a sharp node (because the distance between the node and one or both handles will be zero).


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Hi Alfred,
If you click with the Pen Tool over an existing node (with handles or not doesn't matter) and drag it, you will extend/create a new set of handles for that node as if the node was created from scratch (thus eliminating the previous handles config).

Raskolnikov,
The Pen Tool only creates  new nodes if you click on en empty space on a path. If you click over an existing node you can extend a new set of handles from it and additionally if you press and hold shift they can be aligned with the vertical/horizontal axis (in 45º degrees steps). What's not possible is to align existing node's handles directly with the Node Tool.

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What is/was the actual question here?

Was it to reconstitute the original blobbish shape back into a "regular" circle?

Or

For any irregular blob, how does one change all handle to be both: aligned to an axis and equal length?..... which would not necessarily result in a "regular" shape.

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from blob to circle the lenght of the handles is R / 1.811.

 

 

 

 

reconstruct.png.929d6cef1be53f69241a69d7b0c2b7bc.png


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2 hours ago, MEB said:

Hi Alfred,
If you click with the Pen Tool over an existing node (with handles or not doesn't matter) and drag it, you will extend/create a new set of handles for that node as if the node was created from scratch (thus eliminating the previous handles config).

 

Thanks, Miguel. It wasn't clear to me earlier that you meant "new" in the sense of replacement handles rather than additional ones, but your intended meaning has now penetrated my thick skull!


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47 minutes ago, dutchshader said:

from blob to circle the lenght of the handles is R / 1.811.

Somewhat off topic, but I have read that it is not possible to create a perfect circle using bezier curves, only to approximate one. Using a search term like "Bezier to circle" finds many topics about this, from highly technical articles like http://spencermortensen.com/articles/bezier-circle/ to somewhat simpler discussions like https://stackoverflow.com/questions/1734745/how-to-create-circle-with-bézier-curves

 

Among other things, this implies that using "Convert to curves" on a circular ellipse in Affinity results in an approximation with (hopefully) minimal deviation from a perfect circle ... or maybe that a circular ellipse is not a perfect circle to begin with?


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added a circle around the bred circle, looks round to me

Untitled.png.8fe7c685d5ea8fd8c94e4abbda25e78b.png


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4 minutes ago, dutchshader said:

added a circle around the bred circle, looks round to me

As per the Spencer Mortensen article, the "radial drift" (a measure of the deviation from a perfect circle) can be made very small, on the order of 0.019608, so visually the difference can be made almost imperceptible, but it is still there.

 

Of course, this assumes that Affinity's Ellipse Tool can make a perfect circular vector shape to begin with, which may not be true.

 

12 minutes ago, JimmyJack said:

Blob (that particular blob that is) to Circle:

1) Select all nodes and convert to sharp.

2) use corner tool to reconstitute the circle (all nodes at once)

How do you determine the corner radius that produces a (near) perfect circle from that or any other similar blob shape? When I try it, adjusting the radius in the context toolbar sort of snaps to a value that looks smoothly circular, but after 'baking' the corners I end up with several extra nodes & using the Move tool to proportionally scale & position the shape over an existing circular ellipse reveals that it isn't a particularly good fit.


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23 minutes ago, R C-R said:

How do you determine the corner radius that produces a (near) perfect circle from that or any other similar blob shape? When I try it, adjusting the radius in the context toolbar sort of snaps to a value that looks smoothly circular, but after 'baking' the corners I end up with several extra nodes & using the Move tool to proportionally scale & position the shape over an existing circular ellipse reveals that it isn't a particularly good fit.

 

It's a very specific blob. That's why I mentioned it it the first place.

It's a distorted circle. Changing to sharp nodes produces a square (at 45ª). 

Corner tool brings it back to a circle. I used the on canvas controls... and pushed it past the intersecting point.

(in reality, if the corners are baked, that will leave pairs of points on top of each other. But that's part of the whole pen/node tool reboot I hope to see in the future)

 

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2 minutes ago, JimmyJack said:

It's a very specific blob. That's why I mentioned it it the first place.

It's a distorted circle. Changing to sharp nodes produces a square (at 45ª). 

Hmmm. Unless I missed it, there has been no afdesign file attached to this topic. So what I did was to approximate the blob curve from the screenshot in the first post, matching the nodes & handles as closely as I could to that. I also tried a few variations, but always with 4 nodes in roughly the same locations on the path shown in the screenshot.

 

In no case did changing to sharp nodes produce a perfect square, even when I aligned the left & right nodes vertically and/or the top & bottom ones horizontally. There was always an asymmetry, unless I cheated & snapped each node to a circle (circular ellipse) drawn behind the blob & snap-aligned all 4 nodes to the centerlines of that circle.

 

So while the blob could be considered a distorted circle, unless I am missing something, in all but a very contrived version, its nodes lack the positional symmetry for your suggested method to turn it into a good approximation of a true circle.

 

Apart from that, using the Corner Tool significantly reduces the area of the blob & pushing past the intersecting point creates 'baked' nodes that (in my experiments) creates two pairs of nodes that are not quite coincident on one side & two pair on the other that are.

 

So in light of all this, for the @Raskolnikov criteria for regular shapes ("parallel sides or symmetryc nodes, handles... etc.") I think that since it is going to be an approximation regardless, the best solution is just to pick the Affinity shape tool that most closely approximates the desired 'regularity' of the blob, draw that shape over the blob, tweak to fit, & delete the blob -- IOW, just replace the blob with something more regular (& usually with the minimum/optimum number of nodes/control handles).

 


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2 hours ago, R C-R said:

Hmmm. Unless I missed it, there has been no afdesign file attached to this topic. So what I did was to approximate the blob curve from the screenshot in the first post, matching the nodes & handles as closely as I could to that. I also tried a few variations, but always with 4 nodes in roughly the same locations on the path shown in the screenshot.

 

The way I saw the initial image was... how to wrestle a tweaked circle back into a circle. 

So I started with..... wait for it...... a circle. Points are exactly where they need to be.

 

2 hours ago, R C-R said:

.....in all but a very contrived version,...

 

Yeah, that's what I said. Several times.

 

2 hours ago, R C-R said:

....criteria for regular shapes ("parallel sides or symmetryc nodes, handles... etc.").

 

 

Different problem. Hence my initial question.

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this was the question:

16 hours ago, Raskolnikov said:

What would be the best and easiest way to make the left shape looks like the right shape? Making the nodes having the same curve on both sides.

 

and if this is true:

10 hours ago, R C-R said:

As per the Spencer Mortensen article, the "radial drift" (a measure of the deviation from a perfect circle) can be made very small, on the order of 0.019608, so visually the difference can be made almost imperceptible, but it is still there.

 

Of course, this assumes that Affinity's Ellipse Tool can make a perfect circular vector shape to begin with, which may not be true.

 

then there is no way i could have done this any better i guess


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11 hours ago, JimmyJack said:

Yeah, that's what I said. Several times.

I see that now. I thought when you said "(that particular blob that is)" you were talking about the one in the first or second screenshot, which is why I wondered if there was an attached file I had missed. :S

 

11 hours ago, JimmyJack said:

Different problem. Hence my initial question.

It is an interesting question. To the extent "regular shape" means "regular polygon," only straight sided shapes with equal angles & sides are considered regular, so a circle would in that sense not be regular, nor would any shape with any curved edges. I know there is a different kind of regularity (so to speak) that involves planes of symmetry that would include circles, ellipses, & any of the shapes Affinity's shape tools create when constrained with the shift key, but my addled old brain cannot dredge up the name for that. Can anybody help me out with that?

 

Anyway, without some clear definition of the type of regularity desired, I have to wonder if there is any way for the developers to add a "regularizing" function to the Affinity apps.


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26 minutes ago, R C-R said:

To the extent "regular shape" means "regular polygon," only straight sided shapes with equal angles & sides are considered regular, so a circle would in that sense not be regular, nor would any shape with any curved edges.

 

But what is a circle, if not a regular polygon with an infinite number of sides? stirthepot.gif

 

You could, of course, construct a perfect circle from Bézier curves using an infinite number of segments, but although you might aim for more than four or eight segments it isn't really practical for most users to go much beyond twenty.


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