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From: ingo
Subject: Fishtail math ><}}}*>
Date: 19 Nov 1999 05:08:04
Message: <8E83722CAseed7@212.120.113.81>
I'm trying to animate the tail of an ASCII-fish. I figured out how to do it 
the long way but I'm looking for a short cut.

Concider eleven spheres on a string from the origin to <10,0>. 


around the current position of the second sphere.
3. leave the first and second sphere in its position. rotate the whole 

.
.
.

sphere.

Now, is there a direct way to calculate the position of a sphere, without 
going through the above loop. What will the position of sphere 7 be when 


Ingo

-- 
Photography: http://members.home.nl/ingoogni/
Pov-Ray    : http://members.home.nl/seed7/


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From: Peter Popov
Subject: Re: Fishtail math ><}}}*>
Date: 19 Nov 1999 10:55:58
Message: <gXE1OEmQIwaKCy6cD1iiNG2nHd=4@4ax.com>
On 19 Nov 1999 05:08:04 -0500, ing### [at] homenl (ingo) wrote:

>I'm trying to animate the tail of an ASCII-fish. I figured out how to do it 
>the long way but I'm looking for a short cut.
>
>Concider eleven spheres on a string from the origin to <10,0>. 


>around the current position of the second sphere.
>3. leave the first and second sphere in its position. rotate the whole 

>.
>.
>.

>sphere.
>
>Now, is there a direct way to calculate the position of a sphere, without 
>going through the above loop. What will the position of sphere 7 be when 

>
>Ingo

Will you please explain how you will animate this? Will you change the

11*clock?


Peter Popov
ICQ: 15002700


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From: Remco de Korte
Subject: Re: Fishtail math ><}}}*>
Date: 19 Nov 1999 11:20:07
Message: <383578A0.390793C0@xs4all.nl>
ingo wrote:
> 
> I'm trying to animate the tail of an ASCII-fish. I figured out how to
> do it
> the long way but I'm looking for a short cut.
> 
> Concider eleven spheres on a string from the origin to <10,0>.


> around the current position of the second sphere.
> 3. leave the first and second sphere in its position. rotate the whole

> .
> .
> .

> tenth
> sphere.
> 
> Now, is there a direct way to calculate the position of a sphere,
> without
> going through the above loop. What will the position of sphere 7 be
> when

> 
> Ingo
> 
> --
> Photography: http://members.home.nl/ingoogni/
> Pov-Ray    : http://members.home.nl/seed7/

I don't know if I understand your method exactly but I did a similar
thing with a reasonable result using sin/cos-functions. This gives a
nice curve. The position of each sphere is based on its place in the
string _plus_ a clock value. This way the first sphere will move also.
This is easy to avoid by moving the whole string relative to the
translation of this first sphere. Sounds far more complicated then it
actually is 8)

Groeten!

Remco


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From: Peter Popov
Subject: Re: Fishtail math ><}}}*>
Date: 19 Nov 1999 11:33:05
Message: <dXs1OOq1xINLNt=bgKiRd2qGA45t@4ax.com>
On Fri, 19 Nov 1999 17:19:44 +0100, Remco de Korte
<rem### [at] xs4allnl> wrote:

>I don't know if I understand your method exactly but I did a similar
>thing with a reasonable result using sin/cos-functions. This gives a
>nice curve. The position of each sphere is based on its place in the
>string _plus_ a clock value. This way the first sphere will move also.
>This is easy to avoid by moving the whole string relative to the
>translation of this first sphere. Sounds far more complicated then it
>actually is 8)
>
>Groeten!
>
>Remco

But will this keep the distance between two consequitive spheres
constant? I don't think so, and unless your fish is made of natural
rubber, it's gonna hurt big time :)


Peter Popov
ICQ: 15002700


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From: ingo
Subject: Re: Fishtail math ><}}}*>
Date: 19 Nov 1999 13:22:23
Message: <8E83C37DBseed7@212.120.113.81>
Peter Popov wrote:

>On 19 Nov 1999 05:08:04 -0500, ing### [at] homenl (ingo) wrote:
>
>Will you please explain how you will animate this? Will you change the

>11*clock?


11*clock.

Ingo

-- 
Photography: http://members.home.nl/ingoogni/
Pov-Ray    : http://members.home.nl/seed7/


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From: ingo
Subject: Re: Fishtail math ><}}}*>
Date: 19 Nov 1999 13:23:47
Message: <8E83CA50Eseed7@212.120.113.81>
Peter Popov wrote:

>On Fri, 19 Nov 1999 17:19:44 +0100, Remco de Korte
><rem### [at] xs4allnl> wrote:
>
>>I don't know if I understand your method exactly but I did a similar
>>thing with a reasonable result using sin/cos-functions. ........
>
>But will this keep the distance between two consequitive spheres
>constant? I don't think so, and unless your fish is made of natural
>rubber, it's gonna hurt big time :)

Exactly the reason why I don't want to use the sin / cos method.

Ingo

-- 
Photography: http://members.home.nl/ingoogni/
Pov-Ray    : http://members.home.nl/seed7/


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From: Peter Popov
Subject: Re: Fishtail math ><}}}*>
Date: 19 Nov 1999 15:45:52
Message: <wLY1OMbzDPA1TyjiGtT0qa19CQA+@4ax.com>
On 19 Nov 1999 13:22:23 -0500, ing### [at] homenl (ingo) wrote:

>Peter Popov wrote:
>
>>On 19 Nov 1999 05:08:04 -0500, ing### [at] homenl (ingo) wrote:
>>
>>Will you please explain how you will animate this? Will you change the

>>11*clock?
>

>11*clock.
>
>Ingo

Okay, I'll try to put up a #while loop to do it.


Peter Popov
ICQ: 15002700


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From: Remco de Korte
Subject: Re: Fishtail math ><}}}*>
Date: 19 Nov 1999 15:48:30
Message: <3835B78C.EEB1C568@xs4all.nl>
ingo wrote:
> 
> Peter Popov wrote:
> 
> >On Fri, 19 Nov 1999 17:19:44 +0100, Remco de Korte
> ><rem### [at] xs4allnl> wrote:
> >
> >>I don't know if I understand your method exactly but I did a similar
> >>thing with a reasonable result using sin/cos-functions. ........
> >
> >But will this keep the distance between two consequitive spheres
> >constant? I don't think so, and unless your fish is made of natural
> >rubber, it's gonna hurt big time :)
> 
> Exactly the reason why I don't want to use the sin / cos method.
> 
> Ingo
> 
> --
> Photography: http://members.home.nl/ingoogni/
> Pov-Ray    : http://members.home.nl/seed7/

How much stress will that cause?
And you're not telling me that you've never had to stretch while moving
haven't you?
Anyway, it's probably bad physics for a robot, but it works (for me) in
an image.
If the distance between sphere's really would be the problem you could
easily change your calculations to provide for that. That wouldn't
change the fact that if you had a really 3D-body there still would be
some stretching (inside vs outside of curve).

Remco


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From: ingo
Subject: Re: Fishtail math ><}}}*>
Date: 19 Nov 1999 16:16:44
Message: <8E83E29AAseed7@212.120.113.81>
>How much stress will that cause?
>And you're not telling me that you've never had to stretch while moving
>haven't you?
>Anyway, it's probably bad physics for a robot, but it works (for me) in
>an image.

That's true, but it's like YKYHBRTLW You create a motor using every part 
..... even the ones that don't show ..... just for authenticity. 


Ingo

-- 
Photography: http://members.home.nl/ingoogni/
Pov-Ray    : http://members.home.nl/seed7/


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From: Peter Popov
Subject: Re: Fishtail math ><}}}*>
Date: 19 Nov 1999 16:58:14
Message: <dMc1OCY1+UrtvmpLUIKrpJRSdMCZ@4ax.com>
On 19 Nov 1999 13:22:23 -0500, ing### [at] homenl (ingo) wrote:

>Peter Popov wrote:
>
>>On 19 Nov 1999 05:08:04 -0500, ing### [at] homenl (ingo) wrote:
>>
>>Will you please explain how you will animate this? Will you change the

>>11*clock?
>

>11*clock.
>
>Ingo

//try this

#declare Pos=array[11]

#declare i=0;
#while (i<11) #declare Pos[i]=<i,0,0>; #declare i=i+1; #end

#declare i=1;
#while (i<11)
  #declare Pos[i]=vrotate((Pos[i]-Pos[i-1]),<0,0,10*clock>)+Pos[i-1];
  #declare i=i+1;
#end
Peter Popov
ICQ: 15002700


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