POV-Ray : Newsgroups : povray.animations : Double Pendulum Animation Server Time: 16 Dec 2018 22:29:43 GMT
  Double Pendulum Animation (Message 1 to 9 of 9)  
From: kurtz le pirate
Subject: Double Pendulum Animation
Date: 30 Jun 2018 09:58:33
Message: <5b375449$1@news.povray.org>
Hi,

First basic implementation of "Double Pendulum" mouvement.
Check out at <http://louisbel.free.fr/animate/>

Your comments are welcome.



-- 
Kurtz le pirate
Compagnie de la Banquise


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From: Stephen
Subject: Re: Double Pendulum Animation
Date: 30 Jun 2018 10:29:48
Message: <5b375b9c$1@news.povray.org>
On 30/06/2018 10:58, kurtz le pirate wrote:
> Hi,
> 
> First basic implementation of "Double Pendulum" mouvement.
> Check out at <http://louisbel.free.fr/animate/>
> 
> Your comments are welcome.
> 
> 
> 
Nice! Now using reflective spheres. :-)

-- 

Regards
     Stephen


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From: Bald Eagle
Subject: Re: Double Pendulum Animation
Date: 30 Jun 2018 12:20:01
Message: <web.5b37746a563987a3458c7afe0@news.povray.org>
kurtz le pirate <kur### [at] gmailcom> wrote:
> Hi,
>
> First basic implementation of "Double Pendulum" mouvement.
> Check out at <http://louisbel.free.fr/animate/>
>
> Your comments are welcome.

This is very nice!
How long did it take you implement the code?
I'm glad to see that you're another person playing with the coding challenge
topics   :)    There's lots of fun and educational projects there.

(I still have to fix the last problem I had with converting the Perlin noise
flow field
Coding Challenge #24: Perlin Noise Flow Field
https://www.youtube.com/watch?v=BjoM9oKOAKY
)

I've always wanted to play with some of these systems and have the colors change
as a function of tension, rotational or translational velocity, etc.

1000 frames is "a lot" (Shut it, Balaska)
How long to render the whole animation?


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From: Stephen
Subject: Re: Double Pendulum Animation
Date: 30 Jun 2018 12:23:22
Message: <5b37763a$1@news.povray.org>
On 30/06/2018 13:15, Bald Eagle wrote:
> 1000 frames is "a lot" (Shut it, Balaska)

LOL


-- 

Regards
     Stephen


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From: kurtz le pirate
Subject: Re: Double Pendulum Animation
Date: 30 Jun 2018 15:12:32
Message: <5b379de0@news.povray.org>
Le 30/06/2018 à 14:15, Bald Eagle a écrit :

> This is very nice!
> How long did it take you implement the code?
> I'm glad to see that you're another person playing with the coding challenge
> topics   :)    There's lots of fun and educational projects there.
> 
> (I still have to fix the last problem I had with converting the Perlin noise
> flow field
> Coding Challenge #24: Perlin Noise Flow Field
> https://www.youtube.com/watch?v=BjoM9oKOAKY
> )
> 
> I've always wanted to play with some of these systems and have the colors change
> as a function of tension, rotational or translational velocity, etc.
> 
> 1000 frames is "a lot" (Shut it, Balaska)
> How long to render the whole animation?
> 
> 
> 
> 


Yes, Coding Challenge is a good source of inspiration...

The code took me about 1 hour. The tricky part was the persistence of 
the data between images. Then, 1000 frames, 800x600 with anti-aliasong 
take 15mn.



-- 
Kurtz le pirate
Compagnie de la Banquise


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From: JimT
Subject: Re: Double Pendulum Animation
Date: 2 Jul 2018 12:55:01
Message: <web.5b3a205c563987a3be7517870@news.povray.org>
kurtz le pirate <kur### [at] gmailcom> wrote:
> Le 30/06/2018 à 14:15, Bald Eagle a écrit :
>
> > This is very nice!
> > How long did it take you implement the code?
> > I'm glad to see that you're another person playing with the coding challenge
> > topics   :)    There's lots of fun and educational projects there.
> >
> > (I still have to fix the last problem I had with converting the Perlin noise
> > flow field
> > Coding Challenge #24: Perlin Noise Flow Field
> > https://www.youtube.com/watch?v=BjoM9oKOAKY
> > )
> >
> > I've always wanted to play with some of these systems and have the colors change
> > as a function of tension, rotational or translational velocity, etc.
> >
> > 1000 frames is "a lot" (Shut it, Balaska)
> > How long to render the whole animation?
> >
> >
> >
> >
>
>
> Yes, Coding Challenge is a good source of inspiration...
>
> The code took me about 1 hour. The tricky part was the persistence of
> the data between images. Then, 1000 frames, 800x600 with anti-aliasong
> take 15mn.
>
>
>
> --
> Kurtz le pirate
> Compagnie de la Banquise

I'm guessing what you were passing between frames were the two angles and
angular velocities in order to do a numerical solution of the ODEs. However, I
think your numerical solution scheme is adding energy. You start off with the
balls both stationary and horizontal. Later in the motion BOTH balls are above
the horizontal. A numerical scheme to conserve energy is surprisingly difficult.
What scheme did you use?

Even more surprisingly, there are complex double pendulum motions that are
periodic, many that are symmetric, but several that are asymmetric. Would you
like some data for one (or more) of those motions?

Jim T.


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From: dick balaska
Subject: Re: Double Pendulum Animation
Date: 2 Jul 2018 13:37:13
Message: <5b3a2a89$1@news.povray.org>
On 07/02/2018 08:53 AM, JimT wrote:

> 
> I'm guessing what you were passing between frames were the two angles and
> angular velocities in order to do a numerical solution of the ODEs. However, I
> think your numerical solution scheme is adding energy. You start off with the
> balls both stationary and horizontal. Later in the motion BOTH balls are above
> the horizontal. 

I noticed this too.  But then later they resolve back towards 0. I 
figured the added energy was on purpose for effect.

Welcome to the dark side, where animations are greater than 1 second 
long, Mr. le pirate.
:D


-- 
dik
Rendered 328976 of 330000 (99%)


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From: kurtz le pirate
Subject: Re: Double Pendulum Animation
Date: 7 Jul 2018 15:08:33
Message: <5b40d771@news.povray.org>
Le 02/07/2018 à 14:53, JimT a écrit :
> I'm guessing what you were passing between frames were the two angles and
> angular velocities in order to do a numerical solution of the ODEs.

yes and the last <x,y> position

> However, I think your numerical solution scheme is adding energy. You start off with
the
> balls both stationary and horizontal. Later in the motion BOTH balls are above
> the horizontal. A numerical scheme to conserve energy is surprisingly difficult.
> What scheme did you use?

yes, energy is used but... it's not MY scheme.
In this example, I just adapted the L3 Processing code to POVRay SDL.
And, has i say on my web page, this not a real simaultion.

> Even more surprisingly, there are complex double pendulum motions that are
> periodic, many that are symmetric, but several that are asymmetric. Would you
> like some data for one (or more) of those motions?

If systems of equations defining motion are not too complicated, why not.



-- 
Kurtz le pirate
Compagnie de la Banquise


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From: Bald Eagle
Subject: Re: Double Pendulum Animation
Date: 7 Jul 2018 19:05:00
Message: <web.5b410ec1563987a3458c7afe0@news.povray.org>
kurtz le pirate <kur### [at] gmailcom> wrote:

> If systems of equations defining motion are not too complicated, why not.

IIRC, a double-pendulum is featured somewhere in this movie:
http://www.chaos-math.org/en

Which means that there may be existing code for one somewehere...

Or contact the movie-makers - they may be able to point you in the right
direction.

:)


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