transform origin moves when resizing line

[spinhead]

I want to create a series of lines which rotate around the center of my image, getting longer as they rotate. Concept is, create a line 100px long rotated 0º, CTRL-J, rotate -3º and stretch to 103px, then power duplicate.

But when I stretch the line, the transform origin, originally 100px away, moves as well. (see video)

I haven't been well so my brain don't work so good right now. What am I missing here?

 

 

[GarryP]

Does my attached video help?

Watch what I do in both the Context Toolbar and the Transform Panel.

[spinhead]

Thanks, @GarryP. Close, but not quite. Note that I have the transform origin *outside* the line, off to the left. I'm using exactly the same process (I believe) and when the transform origin is outside the line, it moves when the line length is changed, whether increased or decreased. I can replicate what you're doing here, so I'm pretty sure it's specific to this case.

I'm wondering if it has to do with the method of changing the line size, some sort of CMD-resize or CTRL-resize. Must have my first cuppa and I'll give it a go.

[thomaso]

@GarryP, do you have any idea what's going on with the lengths? I would expect it to increase by your initial 10 px or 10%, but its delta increases, too, resulting in …

0 > 100 px
1 > 110
2 > 121
3 > 133.1
4 > 146.41
5 > 161.051
…
10 > 259.374 (instead of 200 ?) (while the angle remains identically)

[spinhead]

First change is from 100% (the original) to 110%, or a ratio of 1.1 from old to new. It's consistent. It's also on the 'nice to have maybe someday' upgrade list, I suspect, to be able to choose numerical rather than proportional growth . . . but I ain't holding my breath.

[Old Bruce]

17 minutes ago, thomaso said:

do you have any idea what's going on with the lengths? I would expect it to increase by your initial 10 px or 10%, but its delta increases, too, resulting in …

Computers don't do Percent, they do floating point so length plus a 10% increase is the length multiplied by 1.1. We are not Adding ten pixels, we are Multiplying by 1.1.

100 * 1.1 = 110

110 * 1.1 = 121

etc.

[Old Bruce]

Oh, I forgot to mention that I would like the transform origin to remain where I put it, not move out of place. There are other things about Power Duplication that rise up and bite me on occasion, sadly I think it is a case of working by design and me having misplaced expectations.

[thomaso]

On 4/30/2022 at 5:49 PM, spinhead said:

But when I stretch the line, the transform origin, originally 100px away, moves as well.

Possible workaround? (haven't tried): Increase the lengths to the desired transform origin position. Finally subtract the additional unwanted lengths of all objects with a circle shape object + geometry options.

[GarryP]

spinhead: Sorry, I wasn’t watching your video properly. My guess about the Transform Origin moving is because you are resizing the layer and, because the Transform Origin is part of that layer, it gets repositioned relative to the size of the layer. Note that if you use the Node Tool and drag the right-hand node to the left/right, instead of resizing the layer, the Transform Origin does not move.

thomaso: I think that is normal for the power duplicate functionality. It creates the duplicates proportionally according to the relative size of the latest layer versus the previous layer. i.e. 100 + 10% = 110, then 110 + 10% = 121, then 121 + 10% = 133, etc. I don’t know why the angle would remain constant and not change proportionally with the size though.

I think both of these things are expected behaviour. Maybe not ideal in all situations, but expected.
I’m pretty sure that this sort of thing has been mentioned a few times in the forums - maybe a search will find a staff response about it.

[spinhead]

Indeed, @thomaso. I finally realized that @GarryP's first attempt would work in combination with a simple circle. A line from the center, duplicate, resize, change angle, power duplicate, then put a circle over the center. I got stuck trying to make the tool do what I wanted instead of just finding a way to get the result.

@GarryP Exactly correct, but if I use the node tool to resize, it doesn't seem to power duplicate. However, this all seems to be expected behavior, as you say. Thanks for digging in.

[thomaso]

57 minutes ago, spinhead said:

I got stuck trying to make the tool do what I wanted instead of just finding a way to get the result.

Power Duplicate could indeed be more useful if it took into account more than one recent action (e.g. lengths set via the node tool). This leads me to another option: using a Macro as a more sophisticated Power Duplicate tool.

[spinhead]

True. I'm still hoping for scripting someday; only thing I miss about Photoshop.

[JimmyJack]

On 4/30/2022 at 11:49 AM, spinhead said:

I want to create a series of lines which rotate around the center of my image, getting longer as they rotate. Concept is, create a line 100px long rotated 0º, CTRL-J, rotate -3º and stretch to 103px, then power duplicate.

 

So to go around the circle you'd need to hit power duplicate 120 times (even if the center point thing wasn't an issue).
I guess that wouldn't take too much time, but yeeesh 😴. A blend tool would be great right about now 😉.

Affinity sure doesn't make this kind of thing a picnic, but there have to be other ways to get there in fewer chunks. 
Is the floor open to other ideas? Or are you all set at this point.

[spinhead]

Once the first two lines are set, press and hold CMD, press and hold J, 358 dupes in about 10 seconds.

Always open to learn one more thing iffen ya got one.

[JimmyJack]

2 hours ago, spinhead said:

Once the first two lines are set, press and hold CMD, press and hold J, 358 dupes in about 10 seconds.

Always open to learn one more thing iffen ya got one.

AHHH, of course, forgot about the hold 😜.

The "central" problem still remains though right?
I guess the best/easiest way to get the hole in the middle is to mask it out.
We, of course, can't boolean straight lines, and a slice tool doesn't exist.

So.... if you absolutely needed the lines and nothing but the lines I was going to suggest:
Getting your row of lines on a straight text path, adjusting the ramp up in height there (all in one step with Node tool), and then just mapping that onto a circle (also just one step).
The lines can then even be manipulated around the circle with the text arrows. Or, removed from the text parent and just be on their own.

[spinhead]

@JimmyJack Yup. More or less what I did.

[SteveR_UK]

So is it possible say to simply power duplicate a rotating rectangle (like a propeller ) along  the screen (x-axis)? 

As I'm having issues even with this ????

[Old Bruce]

5 minutes ago, SteveR_UK said:

So is it possible say to simply power duplicate a rotating rectangle (like a propeller ) along  the screen (x-axis)? 

No.

[SteveR_UK]

Wow !!!!!, this really does not make sense imo

 

Thanks for the reply

[loukash]

3 hours ago, SteveR_UK said:

So is it possible say to simply power duplicate a rotating rectangle (like a propeller ) along  the screen (x-axis)?

You mean something like this?

[SteveR_UK]

11 hours ago, loukash said:

You mean something like this?

Indeed 

 

[loukash]

Just now, SteveR_UK said:

Indeed

1. power duplicate as usual, the objects will be rotated as in the earlier examples at first, a half circle should suffice
2. roughly distribute them manually across the page, especially the 2nd quarter circle
3. use the Alignment and Distribute buttons in the toolbars

[SteveR_UK]

I appreciate your the reply, a good solution indeed.

However I think the point was not me understanding why this is not the default behaviour of the Power duplicate.

TBH I'm still not understanding the reasons for this behaviour

[thomaso]

14 minutes ago, SteveR_UK said:

TBH I'm still not understanding the reasons for this behaviour

I agree. As you mentioned in your initial thread: If an object gets moved horizontally + rotated there is no reason for a vertical move of a 'power duplicated' object. This feels like a bug to me, too. Oddly, the copy gets shifted vertically regardless of its 'origin transform' position, so even if set to the objects bottom I experience upwards moves in the power copies, whereas if I move horizontally + rotate in the transform panel manually then as expected no vertical offset happens.

[SteveR_UK]

3 hours ago, thomaso said:

I agree. As you mentioned in your initial thread: If an object gets moved horizontally + rotated there is no reason for a vertical move of a 'power duplicated' object. This feels like a bug to me, too. Oddly, the copy gets shifted vertically regardless of its 'origin transform' position, so even if set to the objects bottom I experience upwards moves in the power copies, whereas if I move horizontally + rotate in the transform panel manually then as expected no vertical offset happens.

Spot on, I appreciate the reply.