Find Center Of Line

[ASUNDER]

I have a straight line and want to make it a nice perfect curve, so I have to add a node right in the middle of it.
But I have no idea where the middle of the line is.  I can't find if there is a snapping option somewhere that will show me the middle when my node cursor is in the general vicinity of the middle.  ?  Is there any guides that will also show me different divisions of a line, like four quarters or a third etc. ?

[R C-R]

There are probably better ways to do this but what I would do is duplicate the 2 node curve, rotate it around its center, select the original with the Node Tool & add a node snapped to the intersection with the duplicate. Then I would deete the duplicate.

Much quicker to do than to describe.

[carl123]

A horizontal (or vertical) guide will snap to the middle of that line. The Node Tool will then snap to that middle point

[ASUNDER]

17 minutes ago, R C-R said:

There are probably better ways to do this but what I would do is duplicate the 2 node curve, rotate it around its center, select the original with the Node Tool & add a node snapped to the intersection with the duplicate. Then I would deete the duplicate.

Much quicker to do than to describe.

Ya.  I did that in this case.  I duplicated my line, attached it to the top of the other one, hit Enter, scaled it to 50%, then joined the two end nodes, then converted my new middle node to smooth.  But that is a lot of work instead of just having snapping candidates show possible middle nodes.

Also it didn't work for me to end up with a perfect circle.  The node handles don't seem to want to be able to both move in tandem; the same question I had about moving both sides of a shape from the transform point.  If I could get those two handles the same distance away from the node then I could get a perfect curve.  Guess I will be using ellipses and cutting them in half.  Or I could make some perfect curves and make assets out of them.

 

[R C-R]

1 minute ago, ASUNDER said:

I duplicated my line, attached it to the top of the other one, hit Enter, scaled it to 50%, then joined the two end nodes, then converted my new middle node to smooth.  But that is a lot of work instead of just having snapping candidates show possible middle nodes.

Why all the extra steps like attaching the duplicate, scaling it, etc.? Just duplicate the original & rotate it around its center. Then you can select the original with the Node Tool & add a node snapped to where the two curves cross.

Or use the method @carl123 just posted.

[M1000]

To add a node in the middle between two nodes I would just use "split curve after selected node".

[ASUNDER]

20 minutes ago, carl123 said:

A horizontal (or vertical) guide will snap to the middle of that line. The Node Tool will then snap to that middle point

Not if the line isn't perpendicular to the project it won't.
I thought that a middle snap candidate was an obvious thing that I just couldn't find where the option is.  We can snap to middle of shapes but not lines.  What kind of logic is that?

6 minutes ago, R C-R said:

Just duplicate the original & rotate it around its center.

Ya that's quicker, my fault.

The reason my assets idea isn't very good is if I already drew something, I have a straight line within the other curves, but I've changed my mind that now I want it to be a nice curve.  But I can't do that, apparently.  And an asset would be a similar amount of work as deleting out my line, adding an ellipse and cutting it in half.  These things are too much work.  I'll request a middle line node snap candidate.

[ASUNDER]

3 minutes ago, M1000 said:

To add a node in the middle between two nodes I would just use "split curve after selected node".

Please demonstrate.

[ASUNDER]

I just made some assets that might come in handy.  Some quarter circles and lines that are exactly 1 inch long with segments. 
2,3,4,10 segments and smooth curve nodes.  This might save me some time.

I don't know what the point of naming the assets are, as they don't have a tooltip that shows the name, or have the name displayed at all, and when you go to add it to your project the name is just "curve".  Also if you 'sort by name' you just screwed yourself cause that's a one way trip.  LLLOLOL

It's one of those things can get you into trouble but it can't get you out.
https://www.youtube.com/watch?v=em2apC3u6hc

 

[carl123]

26 minutes ago, ASUNDER said:

I don't know what the point of naming the assets are, as they don't have a tooltip that shows the name, or have the name displayed at all, and when you go to add it to your project the name is just "curve"

Name your curves in the Layers panel before adding them to your assets. Then the asset will use that name

The tooltip should bring up the asset name when you hover over the asset in the asset panel. (You need to hoover over a visible part of the asset, not its bounding box)

When you drag a named asset into your document, the layers panel will show that assigned name

The asset's panel hamburger menu has an option called "Show as list". If you select that option the asset's name will be shown next to the asset

The asset can be renamed in the asset panel by right-clicking the asset BUT that is not recommended as dragging an asset to the document always uses the original name. (Hence, always name them prior to adding to your assets)

 

 

[ASUNDER]

37 minutes ago, carl123 said:

The asset's panel hamburger menu has an option called "Show as list". If you select that option the asset's name will be shown next to the asset

Ah good.  I had to change the background to dark to see the names but close enough.
That works, thanks.

[GarryP]

You can divide any straight line into halves, thirds, quarters, etc. by adding nodes and then distributing the nodes.

See attached video where I divide a diagonal line into three parts by adding nodes at random locations and then using both the Space Horizontally and Space Vertically functionalities.

(For vertical or horizontal lines you only need to use one of the Space functionalities, as appropriate.)

[ASUNDER]

3 minutes ago, GarryP said:

You can divide any straight line into halves, thirds, quarters, etc. by adding nodes and then distributing the nodes.

That's it right there!  Didn't know you could distribute nodes.

[GarryP]

12 minutes ago, ASUNDER said:

Didn't know you could distribute nodes.

It’s not obvious that you can but, then again, there’s nothing that says you can’t.

I was using the software for quite a while before I found out about it.

Tip: With the Node Tool, try selecting some nodes, then switch Transform Mode ON in the Context Toolbar, and see what you can do. Once you know that ‘hidden gem’ all kinds of possibilities open up – see attached video.

[ASUNDER]

Woah

Think I've had enough internet for one day...

[walt.farrell]

6 hours ago, ASUNDER said:

Please demonstrate.

Help: https://affinity.help/designer2/en-US.lproj/pages/CurvesShapes/edit_linesAndShapes.html

Quote

To split curves with a new node:

Do one of the following:

• Ctrl-click (Mac; see help if you're on Windows) the node before the adjoining curve segment you want to add a midpoint node to and select Split Curve After Node.
•  Select a node, then click the same option on the context toolbar.

 

[R C-R]

9 hours ago, ASUNDER said:

10 hours ago, carl123 said:

A horizontal (or vertical) guide will snap to the middle of that line. The Node Tool will then snap to that middle point

Not if the line isn't perpendicular to the project it won't.

??? The line can be at any angle. Try it: just draw a straight line at any arbitrary angle & then drag out a guide from the ruler until it snaps to the middle of the line.

9 hours ago, ASUNDER said:

The reason my assets idea isn't very good is if I already drew something, I have a straight line within the other curves, but I've changed my mind that now I want it to be a nice curve.  But I can't do that, apparently. 

I'm not sure what you mean by "nice curve" but you can use the Node tool to bend a straight line into a curved shape. No need to use assets or otherwise over-complicate this!

[prophet]

14 hours ago, M1000 said:

To add a node in the middle between two nodes I would just use "split curve after selected node".

This seems like the best answer

14 hours ago, ASUNDER said:

Please demonstrate.

 

 

[ASUNDER]

8 hours ago, R C-R said:

??? The line can be at any angle. Try it: just draw a straight line at any arbitrary angle & then drag out a guide from the ruler until it snaps to the middle of the line.

Oh, well that's cool.

Sorry for doubting you.  I assumed by the math that it wouldn't work.  But it seems the devs added that, where it calculates the middle of line automatically.
So that makes me wonder even more; if they already have code to find the center of lines, why they didn't add an optional middle snapping candidate.  That's half as much work as adding a grid line then taking away that line.

8 hours ago, R C-R said:

I'm not sure what you mean by "nice curve" but you can use the Node tool to bend a straight line into a curved shape. No need to use assets or otherwise over-complicate this!

A perfect curve, mathematically.  Not something that I assume is perfect by eyeballing it.  Something that has equal angles between nodes and is easy to work with.  I would arbitrarily choose the length, curve depth etc. but it would still remain "curvy" without deviation.  After adding a perfect half circle to where I want it I'm thinking I will transform it with its bounding box to keep the curve perfect.

In my example I was going to lower the round area of my half circle, to try and show a circumstance where I have an irregular shape that I still want a perfect curve.
But I still don't know how to do that without messing with the perfect curves.  Except a half circle has a middle node that I can select and move in a straight line.  This is why I want perfectly centered nodes.  The geometry space divisions is currently the fastest way to get a center node, I think.

I agree, no need to complicate things.  That's why I come on the forum to ask for better ways, because I'm out of my league in this craft right now.  I'm thinking there are guys that know some tricks.  Thanks guys for all the help.

[ASUNDER]

4 hours ago, prophet said:

This seems like the best answer

Ok well damn.  That is better.
What I wasn't told was to select the ends first.  And the term "split" sounds like it has side effects to the operation.  That it divides the line or something.

It seems that if I have more than one node in the line it doesn't find the middle of the line, even if I have only the end nodes selected.
The alignment tool "space horizontally or vertically" would be the better option in that instance.  So now I have two options here, thank you.

[R C-R]

1 hour ago, ASUNDER said:

A perfect curve, mathematically. 

There are many different kinds of mathematically "perfect" curves, so I still do not know exactly what it is you are trying to do. (Just search the web on "perfect curve" to see what I mean.)

But if say you want to bend a 2 node initially straight curve so that its two nodes have the same angle, try experimenting with the Node tool & the Shift key -- no need to click anywhere on the curve just drag diagonally anywhere along its length with the Shift key held down & you should see how that works.

And of course, there are the various quick shape tools you can use, plus many other ways to create curves.

[firstdefence]

Terminology is quite important when asking questions, so you have to get creative lol!

A balanced arc is probably a better term for what you want, as opposed to say, a semi-circlular arc. I'm not renowned for my math skills, so I generally use either CAD apps, and or online math calcs like: https://www.omnicalculator.com/math/perimeter for semi circular arcs and focused measurements.  

Because Affinity have used the term curve instead of path like photoshop did, when you talk about a curved curve it gets a bit messy, whereas a curved path is less ambiguous. Also, curves can be straight or angular adding to a confusing terminology when posting so you have to be more specific when talking about curves. I know most affinity are used to the term curve to describe a path (I come from photoshop experience) but to describe a straight curve is a bit weird.

[ASUNDER]

11 minutes ago, firstdefence said:

A balanced arc is probably a better term for what you want

Ya true.  A nice curve.
When I convert a perfect circle into curves and cut it in half I am left with two end nodes and one directly in the middle.  That tells me I can get the best results by having a node in the middle or maybe at 25% or 75% of the lengths of a straight line and go from there.  By "best results" I mean a curve that looks like it could be part of a circle, and having to take the least amount of steps to achieve it.  Something that looks like a pro drew it or a computer.

I still don't like that I can't modify the length of the node handles both at the same time.
But the Alt + Drag to create cusp is pretty cool.

19 minutes ago, firstdefence said:

I generally use either CAD apps, and or online math calcs like:

Get out of here with that math.  They call it aftermath for a reason.  Math, not even once!

 

[ASUNDER]

12 hours ago, R C-R said:

There are many different kinds of mathematically "perfect" curves, so I still do not know exactly what it is you are trying to do.

I don't know what I'm trying to do either.  But I know for sure that I need to do it efficiently.

12 hours ago, R C-R said:

But if say you want to bend a 2 node initially straight curve so that its two nodes have the same angle, try experimenting with the Node tool & the Shift key

Ya, I'm finding the modifier keys really helpful.  I'm way better at shapes now than I was a week ago.

[Alfred]

36 minutes ago, ASUNDER said:

When I convert a perfect circle into curves and cut it in half I am left with two end nodes and one directly in the middle.  That tells me I can get the best results by having a node in the middle or maybe at 25% or 75% of the lengths of a straight line and go from there.  By "best results" I mean a curve that looks like it could be part of a circle, and having to take the least amount of steps to achieve it.

If you want a circular arc, why would you start with a straight line instead of an ellipse?

38 minutes ago, ASUNDER said:

I still don't like that I can't modify the length of the node handles both at the same time.

Me too neither, but having modified the length of one of them you’ll get little marks across both handles when you drag the second one  to the same length as the first.