Snapping to many sided polygons

[richburdon]

By trial and error it seems that polygons with more than 6 vertices don't support snapping.

E.g., if I create a pentagram, I can position circles on each point. If I create a septagon, this no loner works.

I noticed also that snapping doesn't work for other shapes (e.g., star). Intuitively I could imagine from an implementation point of view that some shapes would have too many points and would "pollute" the snap candidates. Is there a way to tune? Also, related, is it possible to position a shape on top of path nodes?

Thanks

[firstdefence]

7 hours ago, richburdon said:

E.g., if I create a pentagram, I can position circles on each point. If I create a septagon, this no loner works.

You mean a Heptagon?
You could snap to the top most point and use Power Duplicate ⌘+J to get the circles onto the other points by moving its centre point to the centre of the Polygon.

7 hours ago, richburdon said:

is it possible to position a shape on top of path nodes?

Are we talking about a linear path, or a curved path or both and which node on the object do you want to position to the path node? you can snap to the path but pinpointing a node, I don't think so yet, you could maybe use guides until this feature is added.

You can snap a node to a guide but you can't snap a guide to a node  also guide creation can't be done while using the Node Tool 

[R C-R]

1 hour ago, firstdefence said:

You could snap to the top most point and use Power Duplicate ⌘+J to get the circles onto the other points by moving its centre point to the centre of the Polygon.

A very precise way of doing this (which also would work if you just want to position one circle on one of the other points of the polygon):

1. Position the circle & its rotation center as in the gif.

3. Duplicate (if you want multiple circles).

3. Instead of dragging the circle's rotation handle on the canvas, in the Transform panel in the R field enter 360/n, where n is the number of sides of the polygon. This will move the circle or the duplicate to the first point counterclockwise from the topmost point.

4. If you want multiple circles, power duplicate as in the gif.

5. If you just want one circle at another point on the polygon, the 360/n expression can be generalized to a*(360/n), where a is the 'point number' counting counterclockwise from the top (with the topmost one being zero).

The important thing here is to make sure the rotation center of the circle has been snapped to the center of the polygon, & that you do not click on one of the 9 anchors in the Transform panel, which would rotate the circle around itself relative to that anchor point.

[Alfred]

59 minutes ago, R C-R said:

the 360/n expression can be generalized to a*(360/n)

You don’t need the parentheses, of course, since a*360/n gives exactly the same result as (a*360)/n or a*(360/n).

[firstdefence]

Precision Method.

[R C-R]

9 minutes ago, αℓƒяє∂ said:

You don’t need the parentheses, of course, since a*360/n gives exactly the same result as (a*360)/n or a*(360/n).

True, but it was drummed into my head long ago by a math professor that parenthetical forms are more explicit & thus what he (or more often his T.A.) expected to see when grading our work. Even 50 years later, it is hard to resist that now ingrained habit. 

[Alfred]

20 minutes ago, R C-R said:

parenthetical forms are more explicit

That’s true for a+360/n, where you might want to rule out the possibility that you meant (a+360)/n, but where only multiplication and division are involved there is no need to be explicit about anything since there is no need to perform the operations in any particular order.

[R C-R]

19 minutes ago, αℓƒяє∂ said:

That’s true for a+360/n, where you might want to rule out the possibility that you meant (a+360)/n, but where only multiplication and division are involved there is no need to be explicit about anything since there is no need to perform the operations in any particular order.

Several of us tried to convince the professor that there is no need to be explicit about things like that but that is the notation he wanted us to use so that is what we got into the habit of using. I am still not sure why he was so adamant about that. Maybe it had something to do with preparing us for working with matrix operations that are not necessarily commutative, or maybe he just enjoyed dominating his students. Either way, it is a hard habit for me to break. 

[Alfred]

7 hours ago, R C-R said:

I am still not sure why he was so adamant about that.

I remember one of my teachers at secondary (i.e. high) school being adamant about something to do with working out an area where the units were not specified: those who performed the calculation correctly and chose inches or centimetres (thereby getting an answer expressed in terms of in² or cm²) were rewarded with full marks, but those of us who expressed the same numerical answer as “square units” were told that it should have been “squared square units”. However, she refused to explain her reasoning.

[toltec]

1 hour ago, R C-R said:

Either way, it is a hard habit for me to break. 

I know all about that. I keep painting white on the computer screen every time I make a spelling mis take (bugger) 

[R C-R]

9 minutes ago, toltec said:

I know all about that. I keep painting white on the computer screen every time I make a spelling mis take (bugger) 

That would explain a lot. 

[richburdon]

Everyone -- thanks so much for your generous answers.

(@RCR -- I used perens liberally too! Cheers.)

BTW, what tool are you using to do the animated screen grabs (Mac?)

 

> Are we talking about a linear path, or a curved path or both and which node on the object do you want to position to the path node?
> you can snap to the path but pinpointing a node, I don't think so yet, you could maybe use guides until this feature is added.

@firstdefence  If I use the Pen tool to draw some lines (i.e., a "curve" say, a zig-zag), I want to snap the center of a circle to any of the points. Perhaps I don't know what a "path" is?
 

 

[firstdefence]

Hi Rich a Path is what the Pen Tool draws but Affinity call it a Curve, the names are pretty much interchangeable, so if someone talks about a Path they are actually talking about a curve, there is no technical difference, the terms in relation to Affinity are the same. In Illustrator a Pen Tool drew a Path, in Affinity the Pen Tool draws a Curve, I've used Illustrator a lot so I have a habit of calling the line the Pen Tool draws a Path but I mean a Curve.

Confused lol!

The animated screen grabs I use Camtasia(Mac and Windows). There is also Screenflow and iShowU for Mac.

Free screen recorders are: Quicktime Player already built into the Mac OS, Recordit and OBS Studio, OBS is a little quirky but easily learnt. In the New OS X (Mojave) arriving in Autumn/Fall they will make recording the screen even easier.

At the moment you cannot snap to a Node  But you can pinpoint where a node is as use guides to effectively mark a + and snap to the guides, this takes a bit of guess work but its all we have for the moment, another option is to draw curves on a grid and place nodes at grid interactions and you can then snap to those grid points.

[Alfred]

3 hours ago, firstdefence said:

a Path is what the Pen Tool draws but Affinity call it a Curve, the names are pretty much interchangeable, so if someone talks about a Path they are actually talking about a curve, there is no technical difference, the terms in relation to Affinity are the same. In Illustrator a Pen Tool drew a Path, in Affinity the Pen Tool draws a Curve, I've used Illustrator a lot so I have a habit of calling the line the Pen Tool draws a Path but I mean a Curve.

I’ve never used Illustrator, but in Affinity Designer there’s an important distinction between curves and paths: a curve has a stroke width (which may be zero) but a path doesn’t. An example of this is creating text on a path by typing the text after clicking on a curve with the Artistic Text Tool; when you do this, the curve disappears and only its path remains.

[firstdefence]

6 minutes ago, αℓƒяє∂ said:

I’ve never used Illustrator, but in Affinity Designer there’s an important distinction between curves and paths: a curve has a stroke width (which may be zero) but a path doesn’t. An example of this is creating text on a path by typing the text after clicking on a curve with the Artistic Text Tool; when you do this, the curve disappears and only its path remains.

Ya learn summit everyday  

[JimmyJack]

16 hours ago, firstdefence said:

At the moment you cannot snap to a Node ....

Sure we can .

We can snap nodes to nodes, to key points on shapes (node-ettes , or however they're classified) or even anywhere on a curve.

The only caveat, afaiaa, is that the snapper has to be a curve(s) object with "full-fledged" nodes.... i.e not a shape. The snappee can be either.... And in the case of snapping to an arbitrary point on a shapes boundary, it doesn't even need to be selected.

Centering is also doable with snapping in the special cases of circles/ellipses with equal crosshair ("+") alignment of nodes through the center. Otherwise it's off to the workaround! 

(I guess I should mention: my post is NOT about how to align an array of circles to the vertices around an object. Solely about node snapping itself.)

sorry 'bout the gif quality. I down sized in the online builder. At the mercy of their resample .

 

[R C-R]

48 minutes ago, JimmyJack said:

The only caveat, afaiaa, is that the snapper has to be a curve(s) object with "full-fledged" nodes....

Also, as your gif shows, for some snapping operations like snapping to the nodes of an open curve, you have to use the Node Tool, select both objects, & all the nodes of the object you are moving.