Power duplicating

[jackamus]

Can 'Power duplicating' be used to create a series of straight strokes that will follow back to an origin that is way off the visible illustration area? By this I mean imagine a series of lines going off to the right to meet at a perspective vanishing point that is at a distance way off to the right of the illustration area. I do have a possible way of doing it but because I do not know how Power duplicating works. I did try to search for it but got nowhere. I'll make my suggestion depending on any replies that I get.

[thomaso]

13 minutes ago, jackamus said:

an origin that is way off the visible illustration area?

Possibly I don't fully understand your question because the answer appears simple: "If you move it there it may be everywhere", in this sample in APub even on the pasteboard of another spread:

[G13RL]

If I've understood the question correctly, you can draw a sloping line to the vanishing point.
Set "Enable Transform Origin" to the vanishing point.
"Ctrl/Cmd + J".
Slightly rotate the line at the end opposite the vanishing point.
Repeat "Ctrl/Cmd + J" as many times as necessary.

[jackamus]

Can I use Power duplication to create the 'C' strokes without having to take them back to the vanishing point?

Power duplicating.afdesign

[jackamus]

4 minutes ago, G13RL said:

If I've understood the question correctly, you can draw a sloping line to the vanishing point.
Set "Enable Transform Origin" to the vanishing point.
"Ctrl/Cmd + J".
Slightly rotate the line at the end opposite the vanishing point.
Repeat "Ctrl/Cmd + J" as many times as necessary.

OK I know how to do that and I've used that many times but if the angle of those strokes were almost parallel the VP would be miles to the right and taking back to the VP would be impractical.

What I am asking is given a top stroke and a bottom stroke being a small angle different, can equally spaced intermediate strokes then be drawn using Power duplication that are only long enough to fit within the work area?

[G13RL]

As far as I know, no. Unfortunately, AD doesn't have a gradient tool for shapes. I'd be delighted if someone were to contradict me.

[thomaso]

27 minutes ago, jackamus said:

What I am asking is given a top stroke and a bottom stroke being a small angle different, can equally spaced intermediate strokes then be drawn using Power duplication that are only long enough to fit within the work area?

Yes, if they have or if you set their common Transform Origin accordingly. If you then divide their current angle difference by the wanted number of new objects you can use the resulting value for the rotation of the new power-duplicate objects.

If you need to detect the common Transform Origin, you could extend the two existing lines (or rather two copies) to their intersection and then use this to snap the transformation origin. If it is outside the page/artboard, "just" zoom out accordingly.

Nevertheless, it may be easier to start from scratch with one line only, especially thanks to the new "data-based" power-duplicate options of V2. (ps: I can't open a/your V2 document)

[jackamus]

Hi Thomaso, Thanks for your suggestion. I have one further question: How do I create a 'common transfer origin'?

[thomaso]

1 minute ago, jackamus said:

How do I create a 'common transfer origin'?

I assume "transfer" was just a typo, right? – And possibly my "common" was misleading? As described above, creating an intersection of two lines in different angles will define the wanted transform origin coordinate. Since it is the same coordinate for both I said "common" … while in fact the Affinity interface doesn't know this if more than 1 object is selected but treats them as group with its own Transform Origin coordinate. If you then select one object only its Transform Origin doesn't have the same position but starts at the object's center again.

I admit, it may be complex to first detect this intersection coordinate ("common") + then use its h/v values to one single selected line which then gets used for Power Duplicate … That's why I said before it maybe easier to start from scratch with 1 line only.

[jackamus]

20 minutes ago, thomaso said:

I assume "transfer" was just a typo, right? – And possibly my "common" was misleading? As described above, creating an intersection of two lines in different angles will define the wanted transform origin coordinate. Since it is the same coordinate for both I said "common" … while in fact the Affinity interface doesn't know this if more than 1 object is selected but treats them as group with its own Transform Origin coordinate. If you then select one object only its Transform Origin doesn't have the same position but starts at the object's center again.

 

I admit, it may be complex to first detect this intersection coordinate ("common") + then use its h/v values to one single selected line which then gets used for Power Duplicate … That's why I said before it maybe easier to start from scratch with 1 line only.

I do see what you are getting Thomaso.

How about this workaround. its what I have been doing in the past. If the angle between the two original lines is very small thus the 'a common origin' (vanishing point)' for both of them may be a long way off to the right then I used to zoom out far enough to see the origin and snap the ends of each line to this point. I then move the 'Transform origin' for both these lines to coincide with their common snapped nodes. This will give me 2 lines that I use later.

I then zoom back out again and using the Node tool select the end of one of the lines then copy and paste it and use it as a third line that goes off to the vanishing point. I usually make these lines red to distinguish them from my usual black drawing lines.

When I do 2 or 3 point perspective I do the same thing with the other vanishing points. This allows me to draw lines with the correct VP convergence.

So I can continue to do this like I have always done. Its just that I thought that I might be able to use Power duplication in some way to create many of there vanishing lines.

 

[thomaso]

8 hours ago, jackamus said:

How about this workaround

If I understand right, your 'actual' goal is to create a (snapping?) grid for a later drawing in a vanishing point perspective. Though you could easily create nearly any density of lines with Power Duplicate, as demonstrated above by @G13RL, I think it wouldn't work well because either the density of lines is too low (and thus is missing some guide lines for a later drawing) or too high (and thus snapping at too many lines).

Instead, it may work to first draw with a different perspective (and using one of the built-in Affinity grids) and then, once you have completed the illustration, bend its parts as groups to the desired perspective using available tools such as APh's "Perspective Tool" or, for vectors, the "Warp" feature in AD v2.

This video shows the possible problems = required grid complexity for drawing in a vanishing point perspective in AD v1 :
https://youtu.be/FE8bTRzdurk?si=zXcm0P3_9fW_EEJM

This video demonstrates the use of the "Warp Live Filter" in AD v2:
https://www.youtube.com/watch?v=0-FMHmV_fFc

In case your goal is a correct / perfect drawing in a vanishing point perspective you might consider to use a CAD application that enables you to choose the perspective. This reminds me to your recent thread about Affinity snapping issues in a technical drawing / construction:

[Oufti]

8 hours ago, jackamus said:

How about this workaround. its what I have been doing in the past. If the angle between the two original lines is very small thus the 'a common origin' (vanishing point)' for both of them may be a long way off to the right then I used to zoom out far enough to see the origin and snap the ends of each line to this point. I then move the 'Transform origin' for both these lines to coincide with their common snapped nodes. This will give me 2 lines that I use later.

If the vanishing point is really far, you could use this (very old fashion) geometric property.

[Click for maths…]

 

— In the following example, actually only steps 5 to 7 are really relevant. Previous are just preparation:

1. Create a home-made snapping target

2. Duplicate it as many times you need

3. Align vertically and distribute/space. Group

4. Or Power duplicate, at any spacing. Group

5. Once you've got this, place it and reduce vertically to fit on the two guiding lines, A and B.

6. Duplicate and reduce size to fit somewhere on the right of the guiding lines — Keep the two groups parallel

7. Trace intermediate lines between

 

 

[thomaso]

12 hours ago, jackamus said:

What I am asking is given a top stroke and a bottom stroke being a small angle different, can equally spaced intermediate strokes then be drawn using Power duplication that are only long enough to fit within the work area?

@Oufti's recipe with 'snapping targets' as separate, additional objects remind me to the option to align nodes of several objects evenly, so for instance all start or all end nodes of your power duplicated lines. By aligning their nodes you don't need to care yourself for the differing, varying angles between the bottom and the top line you want to start with.

Your question regarding work area or pasteboard doesn't matter in my eyes, you can move the entire set of lines or do the alignment anywhere on the pasteboard. To visually limit a final set of very long lines to a certain lengths you can nest them in a clipping rectangle. However, I still think this way to create a drawing in this perspective maybe rather cumbersome than comfortable.

[jackamus]

Thanks for all your various suggestions and I have looked at them and find they are quite cumbersome and I don't think help me too much on the way that I am currently doing i.e. Zooming out to create distant vanishing points and creating two or 3 (for 3 point perspective) construction lines from each VP with their respective 'Transorm origins' and node snapped to their respective VPs then zoom back and use the other end node to move the construction line as I desire and draw my drawing line to match it.

The only item I have picked-up on is what is a 'snapping target'? How do you use them?

 

[thomaso]

2 hours ago, jackamus said:

creating two or 3 (for 3 point perspective) construction lines

Two or three only? … or additional, intermediate lines via Power Duplicate, as you requested earlier:

21 hours ago, jackamus said:

What I am asking is given a top stroke and a bottom stroke being a small angle different, can equally spaced intermediate strokes then be drawn using Power duplication that are only long enough to fit within the work area?

My last video, and I assume also @Oufti's recipe, concern the creation of such intermediate lines. Also your attached AD file seems to show this task (while I do see the file's preview only in my lack of V2 ability.)

Note, you also can set a position, lengths and angle for a straight 2-node-curve via the Transform Panel, without the need to zoom in/out (which appears to be the part you want to avoid, correct?). If you set the anchor in the Transform Panel accordingly you can distinguish between start and and node of a line without the need to have this node only selected.

The efficiency of the various options may also depend on your entire setup, including the final illustration you want to achieve. Any forum's comment can be more precise and matching if you upload a screenshot of such a scenery. (I know you attached an AD file / unfortunately I can't check its full content in V1)

2 hours ago, jackamus said:

what is a 'snapping target'? How do you use them?

I used 'snapping target' as any element that may get snapped, usually but not necessarily by another object. The snapping options listed in the "Snapping Manager" dialog and in the 5 "Snap" buttons in the Context Toolbar are 'snapping targets" in my understanding. (While a Transform Origin can't be used as a snapping target for other objects).

[jackamus]

11 hours ago, thomaso said:

If I understand right, your 'actual' goal is to create a (snapping?) grid for a later drawing in a vanishing point perspective. Though you could easily create nearly any density of lines with Power Duplicate, as demonstrated above by @G13RL, I think it wouldn't work well because either the density of lines is too low (and thus is missing some guide lines for a later drawing) or too high (and thus snapping at too many lines).

Instead, it may work to first draw with a different perspective (and using one of the built-in Affinity grids) and then, once you have completed the illustration, bend its parts as groups to the desired perspective using available tools such as APh's "Perspective Tool" or, for vectors, the "Warp" feature in AD v2.

This video shows the possible problems = required grid complexity for drawing in a vanishing point perspective in AD v1 :
https://youtu.be/FE8bTRzdurk?si=zXcm0P3_9fW_EEJM

This video demonstrates the use of the "Warp Live Filter" in AD v2:
https://www.youtube.com/watch?v=0-FMHmV_fFc

In case your goal is a correct / perfect drawing in a vanishing point perspective you might consider to use a CAD application that enables you to choose the perspective. This reminds me to your recent thread about Affinity snapping issues in a technical drawing / construction:

 

7 minutes ago, thomaso said:

Two or three only? … or additional, intermediate lines via Power Duplicate, as you requested earlier:

My last video, and I assume also @Oufti's recipe, concern the creation of such intermediate lines. Also your attached AD file seems to show this task (while I do see the file's preview only in my lack of V2 ability.)

Note, you also can set a position, lengths and angle for a straight 2-node-curve via the Transform Panel, without the need to zoom in/out (which appears to be the part you want to avoid, correct?). If you set the anchor in the Transform Panel accordingly you can distinguish between start and and node of a line without the need to have this node only selected.

The efficiency of the various options may also depend on your entire setup, including the final illustration you want to achieve. Any forum's comment can be more precise and matching if you upload a screenshot of such a scenery. (I know you attached an AD file / unfortunately I don't see its content in V1)

I used 'snapping target' as any element that may get snapped, usually but not necessarily by another object. The snapping options listed in the "Snapping Manager" dialog and in the 5 "Snap" buttons in the Context Toolbar are 'snapping targets" in my understanding. (While a Transform Origin can't be used as a snapping target for other objects).

I don't think I made myself very clear to start with.

So I'll start again. It was when I discovered 'Power duplication'. I thought it might be used to draw multiple lines back to a single point i.e. a perspective vanishing point.

Form all the various suggestions made this was not to be the case as I envisioned it. Now I know that a snapping target is not s 'special' feature but simply another way to call a snapping node.

I'm content to continue in the way that currently use. Many thanks to all.

[jackamus]

14 minutes ago, thomaso said:

Two or three only? … or additional, intermediate lines via Power Duplicate, as you requested earlier:

 

I was referring to just 2 or 3 lines extending back to 2 or 3 vanishing points. The other perspective lines I thought could have been generated by 'Power duplication'. I was wrong.

[thomaso]

53 minutes ago, jackamus said:

'Power duplication'. I thought it might be used to draw multiple lines back to a single point i.e. a perspective vanishing point.

Form all the various suggestions made this was not to be the case as I envisioned it. Now I know that a snapping target is not s 'special' feature but simply another way to call a snapping node.

Thanks for clarifying. I understand that you want a specific, user-defined, global 'target' (= a single x/y coordinate) already taken into account for the end node when drawing any line. Yes, this would make it a lot easier (or be a condition) for drawing in a vanishing point perspective. Also, this maybe easier if Affinity would have a line tool that could only create straight 'curve' objects (without the Bézier options of the Pen Tool which enable us to change the direction of a curve via click-drag while drawing).

Both, a "vanishing point perspective grid" and a "straight line tool" have been requested already in the feature request forum but apparently were not implemented yet.

"snapping target": the Affinity UI also calls them "candidates", including bounding box, mid points, curve or node – whereas you would rather need one (or 2-3) exclusive coordinate(s) as possible snapping candidates, ignoring all other objects and coordinates for snapping.

[Oufti]

1 hour ago, jackamus said:

It was when I discovered 'Power duplication'. I thought it might be used to draw multiple lines back to a single point i.e. a perspective vanishing point.

 

You can do this to have equally spaced lines, originating from a same point:

1. Draw a straight line with Pen (click on the first point, double-click on the end point)
2. Change to Move tool
3. Duplicate the line in place with cmd/ctrl-J
4. In the Transform panel, select an extremity of the line as reference point for transformation (see picture)
5. Rotate it as you like still from the transform panel (see picture)
6. Repeat cmd/ctrl-J to create new lines, all from the same origin and repeating angles. 
    

[thomaso]

2 hours ago, thomaso said:

Note, you also can set a position, lengths and angle for a straight 2-node-curve via the Transform Panel, without the need to zoom in/out (which appears to be the part you want to avoid, correct?). If you set the anchor in the Transform Panel accordingly you can distinguish between start and and node of a line without the need to have this node only selected.

23 minutes ago, Oufti said:

Rotate it as you like still from the transform panel 

Especially this is the problem when drawing in a vanishing point perspective: each line requires a different angle that is unknown before & while it gets created – but is only displayed afterwards.

[Oufti]

Yes, we explained the same thing differently.  

 

37 minutes ago, thomaso said:

55 minutes ago, Oufti said:

Rotate it as you like still from the transform panel 

Especially this is the problem when drawing in a vanishing point perspective: each line requires a different angle that is unknown before & while it gets created – but is only displayed afterwards.

And indeed there are limitations:

Power Duplicate is only made for even distribution (the same transformation, move, resize or rotate, is repeated any times).
And, if you have top and bottom lines predefined, you'll need to calculate the angle between and divide it by the number of lines you want in. So I think distributing the nodes as you proposed is easier in this case

If an irregular distribution is to be preserved, I think it's better to use the theorem above, with a pair of parallels intercepting rays with a common starting point (since ratios are preserved in similar triangles). 

[henryanthony]

Hmmm... Interesting discussion but, but, just saying, seems like a lot of work to mimic 3D functionality in a 2D program. In Blender -  which is a free program - the initial screen upon startup is a perspective grid that can be zoomed, rotated and panned at any angle. Why not just take a screen shot and paste that into AD as a grid to draw on? I know, some like to do things in the way that they like to do things but sometimes it may be better to look at the goal rather than the road used to travel there. 

[jackamus]

19 minutes ago, henryanthony said:

Hmmm... Interesting discussion but, but, just saying, seems like a lot of work to mimic 3D functionality in a 2D program. In Blender -  which is a free program - the initial screen upon startup is a perspective grid that can be zoomed, rotated and panned at any angle. Why not just take a screen shot and paste that into AD as a grid to draw on? I know, some like to do things in the way that they like to do things but sometimes it may be better to look at the goal rather than the road used to travel there. 

1 hour ago, Oufti said:

I tried to download Blender but I can't get passed the 'Donate' window. I thought it was free!

This could be useful when drawing  a perspective grid where the lines can be used as guides for drawing. I would add that because the lines are equidistant apart it must not be confused a being some kind of drawing scale. I have spent many hours drawing a grid and then trying to find a way to create scaled divisions along an X, Y and Z axis.

[henryanthony]

Blender is free. Donation is requested but not required to download, install, and use the program as you wish.

@jackamus You wrote, "This could be useful when drawing  a perspective grid where the lines can be used as guides for drawing. I would add that because the lines are equidistant apart it must not be confused a being some kind of drawing scale. I have spent many hours drawing a grid and then trying to find a way to create scaled divisions along an X, Y and Z axis.

The grid divisions in Blender are scaled and can be changed as needed. 

[thomaso]

1 hour ago, jackamus said:

I have spent many hours drawing a grid and then trying to find a way to create scaled divisions along an X, Y and Z axis.

In a 2D application like Affinity, this can be an unsolvable approach because the Z axis is missing as a property specifically of vanishing point perspective. For this reason, you are forced to simulate this dimension with lines at varying angles, while each single subdivision guide and illustration line max require a different, unique angle.

And this is also the reason why various hints to 3D / CAD apps were mentioned occasionally in your threads about snapping and technical / construction drawings. (for instance)