Sine Wave Along a Curve, Attractor Points to Vary Amplitude & Frequency Along Curve

I would like to create a sine wave that follows a curve, where the frequency of the sine wave can vary at specified points. The variation of frequency can be controlled by user input as only a limited amount of points will be needed.

(right) To the right is a sketch of the desired outcome.

For now, I am only interested in this as a 2d curve to use for a circulation diagram, but it is a nice representation of energy dissapation that could be used in other ways.

(below) This is the definition I'm using for the Sine wave following a specified curve, but cannot figure out how to alter the Amp & Freq at only specified points. (attached)

Attachments:

sine wave along curve.gh, 7 KB

Replies to This Discussion

Permalink Reply by Armin Seltz on December 29, 2016 at 8:15am

Hello Karl,

wow, what a challange! Have a look at my attempt. Its not perfect yet, because where the 2 frequencies meet, it should blend seamlessly, but I think its a good starting point.

I also used a much simpler (ie. faster) way to calculate the points using just vectors and no planes.

Hope it helps!

Attachments:

sinewavealongcurve_as.gh, 20 KB

Permalink Reply by David Rutten on December 29, 2016 at 10:56am

That is a challenge, and I'm not happy with this solution. Much too discontinuous.

Attachments:

customsine.gh, 16 KB

Permalink Reply by Laurent DELRIEU on December 29, 2016 at 1:08pm

Here is my contribution, I interpolate a curve at the top of each inflexion (max and min) of the curve. You have to feed the number of inflexions you want, the amplitude and the frequency multiplier.

Permalink Reply by Armin Seltz on December 29, 2016 at 1:12pm

Nice - getting closer! Do you mind sharing your .gh file?

Permalink Reply by Laurent DELRIEU on December 29, 2016 at 1:14pm

I forgot file !

I think I have an error. Not enough check !

Attachments:

sin_wave_along_curve.gh, 34 KB

Permalink Reply by Laurent DELRIEU on December 29, 2016 at 3:18pm

I change the interpolate function, because I needed an interpolate but not to get the y giving the x but getting the x for a y given. I use curve intersection to do that. There must be a simpliest way.

Attachments:

sin_wave_along_curve_2.gh, 39 KB

Permalink Reply by Bohmwave on October 8, 2017 at 12:50am

He just needs to implement FM in GH. It's an intermediate function.

Attachments:

FM-2017-01.PNG, 154 KB

Permalink Reply by Karl Kachele on January 8, 2017 at 1:32am

This turned out to be much more advanced than I realized, and a bit beyond me. I am still deciphering the definitions you've created. They were good enough for my current needs, but I hope to continue refining this as I learn more. I appreciate all the help!

Permalink Reply by Bohmwave on October 8, 2017 at 12:45am

Karl,

Were you trying to do FM synthesis waves in GH? If so, check the wiki.

Permalink Reply by Lozov on October 13, 2017 at 9:22am

Hi Bohmwave,

I've looked at you image, but couldn't figure out what you meant and how to recreate your results. I'm particularly interested in the purple curve... Could you post your grasshopper file? Thanks so much!

Permalink Reply by Bohmwave on October 21, 2017 at 7:58pm

see adjacent comment. Purple curve is 1st derivative of green one. it plots the points of green curve's zero-crossing as max-min, and max-min as zero crossings.

http://www.grasshopper3d.com/forum/topics/sine-wave-along-a-curve-a...

Permalink Reply by Karl Kachele on October 13, 2017 at 10:23am

Bohmwave,

Perhaps I was, though not consciously. At the time I just needed it as a graphic tool to show intensity of pedestrian traffic. Your solution here looks great though, I am interested in applying this to other form-making processes.

Could you share some more insight for how to create FM Synthesis Waves? A link to the 'wiki' or your definition?

Thank you