New shape tool: Wave tool

[Dimenta]

It would be nice to have a wave tool to make sine and cos waves with different parameters: wave count, wave height, wave curve (curving in a fibonacci style) etc.

Does anyone have approach for easily making a wavy line? My best solution is doing a line and turning on grid snap and then manually adding points and tweaking them to make a wavy line and then copy that line and fuse them together. Any other hacks?

[GarryP]

There might be something useful in one or more of these threads (found by searching the forums for wavy line )

https://forum.affinity.serif.com/index.php?/topic/190560-how-do-i-make-a-wavy-line-that-looks-like-water/

https://forum.affinity.serif.com/index.php?/topic/193656-wave-or-image-decorations-for-title/

https://forum.affinity.serif.com/index.php?/topic/189767-creating-zig-zags-and-wavy-lines-from-stroke/

https://forum.affinity.serif.com/index.php?/topic/157890-how-to-draw-this-wavy-line/

...and others.

[D.E. Main]

I agree with the original post.  I have the ongoing need to have a pure sine curve.   (...and nice to have, other function curves.)  Manual approximation will not work for my need.  (Modeling complex Guilloche patterns for a 1920's engraving rose engine.)   

I've tried manual approximations using the sine function and tracing images of sine and other functions manually.

None of the above examples meet my needs.

 

[Bit Disappointed]

 

I know there are quite a few here and in the graphic industry as a whole who need algorithms, not workarounds for various types of line manipulation:

• Pure sine curves or other types
• Star spikes with a bit of random spike lengths
• And like me, a need for more randomly generated *gentle* variations in a curve, so it appears less mechanical and more organic; this probably falls more into a roughen/smoothen tool category. The pencil tool in sculpt mode is a poor substitue for roughen - it is not that great.

Workarounds devour the time I need to earn money from my work and also take away some of the joy of creating. One thing to understand before developing, choosing not to develop, or advising is that some creatives produce hundreds of details to which workarounds simply cannot be applied. That is precisely why some programs have these features, which people outside the industry with little knowledge refer to as bloat. No, these are tools for others than those who complain about bloat.

[Oufti]

2 hours ago, D.E. Main said:

I have the ongoing need to have a pure sine curve.   (...and nice to have, other function curves.)  Manual approximation will not work for my need.  (Modeling complex Guilloche patterns for a 1920's engraving rose engine.)   

It does not seem to be so easy to achieve… 

On a Mac (you didn't precise what OS you use…), there is an utility Grapher where I drew a curve y = sin x. 
When exported as a vectorial PDF and placed in Affinity, I see that the curve is now a group, divided in many curve segments, each with a lot of nodes (so close that they appear as a fat blue line).

My conclusion is that PDF format (or Affinity alone?) can only offer a mathematical approximation of a sine curve.
Perhaps is it though enough for your needs?

[D.E. Main]

Yup - Sorry .  I'm on a Windows laptop system.  And I can do a graphical approximation but need a continuously scalable object.

 

I'm hoping to exploit the built-in math functions of Affinity Designer.

[Pšenda]

5 hours ago, Oufti said:

utility Grapher where I drew a curve y = sin x. 

For simple functions there is no need to use any special graphics/math programs, just download the curve as SVG from the internet - for example from wikipedia:

 

[fde101]

4 hours ago, D.E. Main said:

need a continuously scalable object.

One problem you are going to face is that as soon as you export it to some vector format it will *always* be an approximation of some sort.  Sine and cosine waves are interchangeable with each other, but neither can be perfectly represented as a Bézier curve, and they cannot be coded into most vector graphics formats.

There is some discussion around this here: https://math.stackexchange.com/questions/4235124/getting-the-most-accurate-bezier-curve-that-plots-a-sine-wave

PostScript does have a few trig functions, including sine and cosine, so PDF might as well (I can't seem to figure out the right search terms to identify this), so it *might* be possible to code this into a PDF, but other vector formats (such as SVG) would only be able to contain approximations.

[Pšenda]

36 minutes ago, fde101 said:

but neither can be perfectly represented as a Bézier curve

Even a circle isn't a "circle" in Affinity 🙂

[2ddpainter]

like to add, there are also a few online SVG wave generators

and Processing could maybe also be helpful ?
https://processing.org/examples/sinewave.html

https://openprocessing.org/sketch/2096187

[D.E. Main]

RE discrete versus continuous functions - I understand.  I rather need reasonably smooth approximations to a level of precision that fits the scale of my needs.  I am modelling at the .01 mm scale. 

 

Better, non-tedious methods to approximate to allow this scale - or rather replicate to this level of precision.

 

Thanks everyone - Dennis

[D.E. Main]

 

9 hours ago, Pšenda said:

For simple functions there is no need to use any special graphics/math programs, just download the curve as SVG from the internet - for example from wikipedia:

 

 

RE wikipedia I did not find a SVG format or was able to Save As svg.  But Thanks, I'll otherwise search for an SVG using Google.

 

But thanks.

[Ldina]

Here's another thread on making sine waves, which may or may not fill your needs.

 

[Pšenda]

1 hour ago, D.E. Main said:

wikipedia I did not find a SVG format or was able to Save As svg

Right click on sine image inserted in my post, then Save image (SVG) as...

[D.E. Main]

Darn.   Well, I tried this which seems to work for now.  I'll be testing the precision and tweaking as I progress.

1. Downloaded a sine image
2. Drew a straight line the length of the image
3. Divided the line into segments for peaks & valleys
4. Selected and moved alternating points to form a 'zigzag' line
5. Smoothed the curves by selecting the nodes and using the Convert: Convert to Smooth

 

Comparing this with the image by overlaying them, this is a fair starting point.  I'll be checking against my engravings for which this will be used.

Thanks everyone!!!

[Pšenda]

4 minutes ago, D.E. Main said:

I'll be testing the precision and tweaking as I progress.

I don't really understand the reason to complicatedly create something that can be easily downloaded from the internet (or from my post) and it will still be an accurate vector sine wave within the required range.

[D.E. Main]

Sorry, but I didn't see your post (to save your svg and hadn't found a reliable one from the internet yet.) before I was trying other methods.

D

[Ldina]

15 hours ago, Pšenda said:

just download the curve as SVG from the internet - for example from wikipedia

@Pšenda Thanks for the great tip! I downloaded sine curves, hyperbolas, parabolas, etc, (SVG format) from Wikipedia, edited and saved them as "Assets" for future use. Now, I can drag them as vector objects into Photo or Designer and manipulate them as I wish. Thanks for teaching me something cool that I didn't know. Awesome!!

[Pšenda]

7 hours ago, Ldina said:

edited and saved them as "Assets" for future use. Now, I can drag them as vector objects into Photo or Designer and manipulate them as I wish.

I'm glad the advice was useful 🙂

If you have created an Asset of these basic math functions, and were willing to share it with other forum users, then you could put it in the Resource forum - I'm sure many users would appreciate it. Alternatively, Serif could take inspiration from this and add similar Assets as part of the installation.

[Ldina]

5 hours ago, Pšenda said:

If you have created an Asset of these basic math functions, and were willing to share it with other forum users, then you could put it in the Resource forum

Good suggestion! I added them to Resources, per your recommendation. 

[Pšenda]

2 hours ago, Ldina said:

Good suggestion! I added them to Resources, per your recommendation. 

Thanks.
I'll just put the link here so that those interested don't have to look for it 🙂

[Ldina]

1 minute ago, Pšenda said:

Thanks.
I'll just put the link here so that those interested don't have to look for it 🙂

Perfect! Thanks.