move objects in radial direction, without scaling (wishlist)

[Brynn]

Hi Friends,
This is a wishlist request.

I would like to suggest (and would use it heavily), some kind of mechanism to move objects in a radial direction. Typically I'll have objects arranged in a circle, such as in the attached radial-move.svg. I'm not sure what to call them, but those 12 blue objects in a circle.

I'd like to be able to move them toward the center of the circle, or away from the center, without scaling them, or changing them in any way.

(Already it's possible to move them, using the option to display handles on selected nodes, or simply using selection/scaling handles. But both of those also scale the objects at the same time. I want to be able to move them, without scaling.)

Even though I typically want this feature when working with objects arranged in a circle, I think this feature could be useful if the objects were not necessarily in a circle, but can be moved radially around an imaginary center of a circle. I can't think of any specific examples where this would be useful, but it would be a way to move multiple objects outward from some central point (or inward). (Well, maybe if you were using Inkscape to make ("frames" for) an explosion animation. The objects wouldn't start out in a circle, but can be moved away from a central point (or inward), without scaling.)

I don't know anything about programming, so I can't really suggest the best way to accomplish this programatically. But just to potentially start a discussion, I'm thinking that maybe a mouse click could identify the central point, around which objects would be moved inward or outward.

However, the problem I see with using just a mouse click, is lack of precision. So maybe when this tool is enabled, a mouse click would place a point on the canvas (not a permenant dot, but just a point or a crosshair maybe) which would be snappable....similar to the rotation center. And/or maybe the x,y values could be entered into X and Y number fields.

To me, it seems like this could be a new function for the selection tool, and the same scaling handles could be used for the movement. Like maybe a "Radial Movement Mode", or "Explode Mode", or something like that. Otoh, perhaps it would be less confusing not to use selection handles, and I could also imagine some kind of slide bar, to control the movement.

While a new mode for the Selection tool makes more sense to me, I guess it could also be done with an LPE or maybe even extension. Thinking of inward radial movemenet without scaling, the objects will start overlapping, sooner or later. And that puts me in mind of a kaleidoscope. So maybe this could be done with an LPE or even extension, which provides other features as well?

Please feel free to ask for any clarifications. I'm available for basic discussion, although again, I'm not a programmer, so I can't discuss that part of it :-)

Thanks for making Inkscape, and thanks for listening!

[Mc (mc...)]

Hi Brynn,

Did you try the "polar" tab of the "Arrange" dialog ? It sort of does some of the things you're asking

[Brynn (brynn4inks-deactivatedaccount)]

I couldn't make it work. Apparently you have to start with the objects not already in a circle. And as far as I understand, it puts the object in a circle. But to be honest, I couldn't figure it out.

[Hachmann (marenhachmann)]

Ping me if you'd like a crash course, Brynn.

[Hachmann (marenhachmann)]

Btw. doesn't the new path effect 'rotate copies' do something like what Brynn requested?

It's only for identical objects, though, so if you're using different blue dots, then you'd have to use snapping or position switching to get them to the correct place.

[Brynn (brynn4inks-deactivatedaccount)]

Thanks Maren,
I think you gave me instructions about using the Polar tab of Arrange dialog before (I brought this up on the mailing list a while back). And I just couldn't make it work. We could try again, if you have time.

For the new LPE, if it's in 0.92, I don't have it yet. "Rotate copies" doesn't seem to describe what I want, but I understand that sometimes terminology can be confusing. I guess most of the time the objects are identical, except they are rotated differently.

Is there a pre0.92 version available for Windows yet?

[Alvin Penner (apenner)]

there are .7z builds available at:
http://download.tuxfamily.org/inkscape/
these are quite up-to-date, but I haven't tried one recently

[Hachmann (marenhachmann)]

Links to videos are in the release notes:
http://wiki.inkscape.org/wiki/index.php/Release_notes/0.92#Rotate_copies

[Brynn (brynn4inks-deactivatedaccount)]

Ok, I haven't tried the new LPE yet. But Maren sent me instructions for using the Polar Coordinates feature, and I've spent a lot of time testing it. It generally does do what I want, with simple shapes. But it doesn't work properly with the way that I create the pieces.

If I use the file I provided above for testing, I can't make Polar Coordinates work properly. It appears that the objects are being rotated, even though Rotate option is unchecked. But I think they really are not being rotated, and instead are being repositioned around the circle, giving the appearance of being rotated. If you give each object a different color before clicking Arrange, you can see it.

I typically create the pieces by starting with a fancy star or spirogram. The only thing those 2 have in common, and which I think is responsible for the malfunctioning, is that those are both one, long, unbroken path, which is twisted and curved into complex designs.

Anyway, starting with a fancy star or spirogram, I usually draw a circle and use it with either Cut Path (or Difference or Intersection), to isolate various parts of the whole path. And then usually a good deal of node editing, to achieve my goal of having a circle of nearly identical individual objects. I'll make some quick (more or less quick) steps to show. Please see attached polcosteps.svg.

The reason I think the objects are being repositioned around the circle, is because the shape starts out as one long path that has been twisted or intertwined by either the Star feature or Spirogram. Once I do the path operation and various node editing, it causes the path to be chopped up into pieces, and when I do the node editing, it puts it back together in a way that the nodes are completely out of order.

When I create several simple shapes, say a triangle (using Pen tool), Polor Coordinates works perfectly. When I finally had the idea that the objects were being repositioned, rather than rotated, I used those triangles for testing. I broke 2 of the nodes in several of the triangles, and moved the resulting path segment to a different triangle than the segment was originally part of. Then I joined the nodes. That took the nodes out of the order they had been in originally.

When I tried Polar Coordinates with those triangles, now they appeared to be rotated, although in fact, they just changed position on the circle.

Thus, for the way that I'm accustomed to working, Polar Coordinates does not work.

I might not be able to test the new LPE for a while. This new Windows 10 system is such a nightmare, that I've decided to revert to Windows 7, yes on this new computer. Windows 10 is so bad, I can't even use it for a backup while I learn how to use a Linux distro.

I'll post here again, once I've had a chance to try that LPE.

Thanks,
brynn

[Brynn (brynn4inks-deactivatedaccount)]

I just wanted to give a little update on this. (A similar issue came up in a forum, and reminded me.)

Now I've tried Rotate Copies LPE. It does move the copies in a radial direction -- sort of. I can't exactly explain what it does....

It seems to move them in a radial direction, except it's relative to the original path. So they move outward from the center of the circle, but they also move as if the original path is the center. And you control it from by moving the center of the circle. I can't really describe it very well, but it would not be helpful for my use case. I don't want to move the circle at all.

So I don't know of any existing tool or feature which provides what I'm asking.

Thanks again :-)

[Brynn (brynn4inks-deactivatedaccount)]

Here's another simple use case. And after I upload the image, I'll try to migrate this report to GL.

There are 12 circles which are arranged in a circle. And another set of 12 circles arranged in a larger concentric circle. And the circles of the 2nd concentric circle are offset relative to the first circle of circles. Please see attached screenshot.

I want to move either the 12 circles in the smaller circle of circles outward just a tiny bit, without scaling them; or move the 12 circles in the larger circle of circles inward just a tiny bit, without scaling them; so that the circles in the smaller circle are touching the circles in the larger circle.

[Brynn (brynn4inks-deactivatedaccount)]

Moved to: https://gitlab.com/inkscape/inbox/issues/671

Closed by: https://gitlab.com/brynn