non uniform scaling

[rwpinto]

Is there a way to non-uniformly scale a drawing?  I can only find uniform scaling, rotation, and shear. 

[Old Bruce]

You can use the Transform panel to scale the Height and Width together or separately. Click on the little icon that is on the right to link the two to preserve the aspect ratio, I think it is supposed to be a chain (get it? Links).

Other things for scaling have a little lock icon between the height and width input fields.

I don't know what you mean by rotation and shear though, those have only the one 'dimension' .

[rwpinto]

Thank you, but I meant something a little different. Suppose you start with a square, and you want to construct a trapezoid by applying one scale factor to the bottom line and a different scale factor to the top line. a point on the sidelines would separate promotional to its distance from the 2 lines. 

[Old Bruce]

Not really, the 'lines' top and bottom are part of the shape. What you can do is set up the Designer Node tool Context Toolbar like this. So when you select both nodes at the top and hold down the Command key (maybe Control on Windows, I don't know for sure) you can move them together. A shape made. with a Shape tool (Rectangle or Trapezoid) will need to be converted to curves first. This was done from a square shape converted to curves.

 

 

[rwpinto]

I understand, but what if you have an arbitrarily large collection of curves within a bounding box. Wouldn't it be nice to be able to differentially scale the collection?

 

[walt.farrell]

7 minutes ago, rwpinto said:

Wouldn't it be nice to be able to differentially scale the collection?

I don't understand why you'd want to do that.

[thomaso]

2 hours ago, rwpinto said:

Suppose you start with a square, and you want to construct a trapezoid by applying one scale factor to the bottom line and a different scale factor to the top line.

If you select nodes with the Node Tool you can use the transform panel to scale them separately, with absolute values or with a scale factor.

Just in case: if you ask for this option to be able to create a perspective drawing maybe it would be easier to work with an accordingly defined grid – though I am not sure if it allows a vanishing point perspective.

 

[rwpinto]

Yes, non-uniform scaling plus shear would give a good approximation to a perspective transformation for reasonably flat renditions of objects. What you show is fine, but I do not want to do that for tons of objects.

For example, construct a large wall of brick-shaped objects. I would like to apply a single transformation to the wall to mimic perspective. 

[R C-R]

1 hour ago, thomaso said:

If you select nodes with the Node Tool you can use the transform panel to scale them separately, with absolute values or with a scale factor.

But doesn't that work only if just two adjacent nodes are selected? IOW, it would not work for other shapes like the one below, right?

[rwpinto]

Affinity would apply a procedural calculation to all the nodes based on relative position.

[thomaso]

2 hours ago, rwpinto said:

What you show is fine, but I do not want to do that for tons of objects.

For example, construct a large wall of brick-shaped objects. I would like to apply a single transformation to the wall to mimic perspective. 

True, can't be done in Affinity to a group of objects. I chose the single square because you mentioned a single square. Now you seem to confirm my assumption that you are actually looking for perspective distortion (which you might mean with "non uniform scaling"). Unfortunately, there is a Perspective Tool only in APh and it only works with pixel layers (vectors are rasterized).

13 minutes ago, R C-R said:

But doesn't that work only if just two adjacent nodes are selected? IOW, it would not work for other shapes like the one below, right?

Yes, it is a limited workaround. For your figure it would work if the two nodes are horizontally or vertically oriented, since the transform panel doesn't offer a distance option and thus the width is used as workaround. But I guess this doesn't matter here because the OP let us know gradually that perspective is desired.

[rwpinto]

Thank you for the information. Perhaps Affinity will provide perspective transformations as part of an upgrade. 

[Old Bruce]

The key word is "Perhaps"....

[prophet]

14 hours ago, R C-R said:

But doesn't that work only if just two adjacent nodes are selected? IOW, it would not work for other shapes like the one below, right?

With those nodes selected, I can click the "Transform mode" button in the Transform section of contextual menu and then do all kind of transforms, both freehand and using the Transform Panel.

[R C-R]

29 minutes ago, prophet said:

With those nodes selected, I can click the "Transform mode" button in the Transform section of contextual menu and then do all kind of transforms, both freehand and using the Transform Panel.

Yes, that is basically the same thing that @Old Bruce suggested earlier in this discussion.

[prophet]

26 minutes ago, R C-R said:

Yes, that is basically the same thing that @Old Bruce suggested earlier in this discussion.

I see that now, but it was apparently not super clear for either of us. I was trying to answer your question directly regarding scaling non-adjacent nodes via the Transform Panel

[thomaso]

55 minutes ago, prophet said:

With those nodes selected, I can click the "Transform mode" button in the Transform section of contextual menu and then do all kind of transforms,

... not really all, for instance perspective distortion of more than 1 object, respectively of several nodes, in a way that affects each node different than others – while it appears to distort only those objects which don't get all their nodes selected and simply scales + moves the other objects.

 

11 hours ago, rwpinto said:

Perhaps Affinity will provide perspective transformations as part of an upgrade. 

Oh, I forgot about an existing feature: The Live Filter > Distort > Perspective.
It has the advantages to be non-destructive + to maintain vector + to be applicable to generic shape objects.

 

[R C-R]

14 minutes ago, thomaso said:

Oh, I forgot about an existing feature: The Live Filter > Distort > Perspective.
It has the advantages to be non-destructive + to maintain vector + to be applicable to generic shape objects.

True, but live filters cannot be created in AD, so if someone does not own AP they can't create this filter.

[thomaso]

@R C-R, why do you mention AD? And why with "but"? – As far I read the OP did not talk about any certain Affinity app, right?

And even if, to me it appears useful generally to point to all existing features – instead excluding available solutions in advance. 😉

[R C-R]

18 minutes ago, thomaso said:

@R C-R, why do you mention AD?

Just to make it clear that AD does not support creating filters, so users unaware of that won't waste time looking for ways to create them in that app.

[thomaso]

1 minute ago, R C-R said:

so users unaware of that won't waste time looking for ways to create them in that app.

I see your general point. But especially in this thread it was rather the OP making the community waste time by guessing what was (is?) actually wanted.

[R C-R]

14 minutes ago, thomaso said:

I see your general point. But especially in this thread it was rather the OP making the community waste time by guessing what was (is?) actually wanted.

To be fair, it is not unusual for people to omit details that would make it clearer what they wanted. Helping them to understand what they need to include & why is one of the reasons this community can be so useful to so many people.

[rwpinto]

Yes, AP seems to have many features that AD does not, but could use. I think that AD could benefit from more general transformation tools to alleviate the burden of trying to be a bit more rigorous about design. I could generate some things in a CAD program and then project to 2D, but AD doesn't seem to accept a DXF file either. 

[thomaso]

2 minutes ago, R C-R said:

Helping them to understand what they need

There is no doubt about this. Again I wonder for what purpose you mention this. – Instead responding "I don't understand why you'd want to do that." like a post before mine, I tried it this way: "Just in case: if you ask for this option to be able to create a perspective drawing" … which finally caused the mentioned "wall of brick-shaped objects" … and my according offer.

Note, we still do neither know if the OP is using AD (as you assumed when mentioning AD's lack of filters) nor what app is available for the OP.

Actually we don't have to know. So, pointing to an existing feature is not at all reduced help or misleading as long no certain app was mentioned by an OP. And, of course there is always the simple option to use the Help menu which will auto-highlight according menu entries + display an animated arrow pointing to the currently selected Help entry. No need to waste time for a search. And in case the help wouldn't work this way on someones computer there is still the option to ask.

1 hour ago, R C-R said:

but live filters cannot be created in AD

Can't you understand that this may confuse as long nobody has mentioned or asked for AD in particular? To me this your response to my filter suggestion sounds like you inform the OP "that answer maybe true but it doesn't work for you", respectively commenting that filter post as being incomplete, wrong or misleading.

Don't have the terms "but" | "additionally" | "besides" quite different meanings, aside their commons?

[R C-R]

2 hours ago, thomaso said:

Note, we still do neither know if the OP is using AD (as you assumed when mentioning AD's lack of filters) nor what app is available for the OP.

I made no assumption about what the OP is using. Like I said, I just wanted to mention that AD lacked this feature so anybody reading this topic who was not aware of that fact would not waste any time looking for it.

Explicitly mentioning that isn't going to confuse anybody so what is the harm in doing that?