Image Vector Brush – stretched / unstreched

[thomaso]

What does it depend on whether areas of a vector image brush curve get stretched or not? In this example the nodes, their handles and their distances are quite the same … but one curve seems to maintain the image aspect ratio across the entire lengths the other curve gets a segment stretched (-> green vs. red). – What is causing the difference and how can I influence this?

[walt.farrell]

There are obvious differences in the control handles to the left/right of the green oval from those to the left/right of the red oval, as well as in the angles of the leading and trailing nodes of each. 

Those probably have something to do with it, but I'm not sure what/why. Any reason for not providing the Affinity file and the brush?

[thomaso]

The node types & handles were my assumption, too. Also the length of the curve influences the image more or less. – But it seems I am unable to change the handles of the right curve in a way that avoids that quite obvious difference in the image's aspect ratio. – attached my V1 file:

vector brush image stretched V1.afpub

[lepr]

24 minutes ago, thomaso said:

What is causing the difference and how can I influence this?

The transformation matrix of an object is influencing how the brush texture is mapped onto the path(s) of an object.

If you select your two curves and do Merge Curves then they will be stroked in a matching way, and then you can do Separate Curves if you require them to be separate objects.

[thomaso]

40 minutes ago, lepr said:

The transformation matrix

Ah, not the node properties or Node Tool caused the image stretching but a scaling of the curve's bounding box with the Move Tool. – Perfect, thank you! – The 'Merge Curves' workaround is quite smart – how did you detect the trick?

Do you also know what influences the resulting brush width if those curves get merged? I experience sometimes the largest width of the merged curves rules, sometimes it results in a very different and much smaller width than any of the initial curve used.

[lepr]

9 hours ago, thomaso said:

how did you detect the trick?

I don't remember - it was years ago when I noticed Merge Curves creates a new object with identity transformation matrix.

 

11 hours ago, thomaso said:

Do you also know what influences the resulting brush width if those curves get merged? I experience sometimes the largest width of the merged curves rules, sometimes it results in a very different and much smaller width than any of the initial curve used.

The new unscaled object that is created by Merge Curves is given the stroke properties of the source object with the lowest position in the stack.

If that source object is being scaled by its transformation matrix and has 'Scale with object' enabled for its stroke, then its apparent stroke width on canvas and in Stroke panel differs from its underlying stroke width. It is the underlying stroke width which is given to the product of Merge Curves.

By the way, the underlying stroke width of an object can be found in Appearance panel.