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From: Bald Eagle
Subject: Vibrating Plate WIP
Date: 4 Mar 2016 21:20:02
Message: <web.56d9fbdd155fef445e7df57c0@news.povray.org>
Re:
http://news.povray.org/povray.newusers/thread/%3C56d9d7a3%241%40news.povray.org%3E/


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From: And
Subject: Re: Vibrating Plate WIP
Date: 6 Mar 2016 08:20:01
Message: <web.56dbe7f25a67670a70456f660@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
> Re:
> http://news.povray.org/povray.newusers/thread/%3C56d9d7a3%241%40news.povray.org%3E/

This is beautiful.


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From: Stephen
Subject: Re: Vibrating Plate WIP
Date: 6 Mar 2016 11:20:24
Message: <56dc1278@news.povray.org>
On 3/4/2016 9:19 PM, Bald Eagle wrote:
> Re:
> http://news.povray.org/povray.newusers/thread/%3C56d9d7a3%241%40news.povray.org%3E/
>

Nice and that is using bicubic patches?

I processed the data (deviation from the average) and used triangles to 
make the plate.



-- 

Regards
     Stephen


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From: Stephen
Subject: Re: Vibrating Plate WIP
Date: 6 Mar 2016 11:22:55
Message: <56dc130f@news.povray.org>
On 3/6/2016 11:20 AM, Stephen wrote:
>
> I processed the data (deviation from the average) and used triangles to
> make the plate.
>
>
>

Oh! the Sphere is hiding one of the data points. :-(

-- 

Regards
     Stephen


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From: Bald Eagle
Subject: Re: Vibrating Plate WIP
Date: 6 Mar 2016 16:15:00
Message: <web.56dc572c5a67670a5e7df57c0@news.povray.org>
Stephen <mca### [at] aolcom> wrote:

> Nice and that is using bicubic patches?

No sir.  Still too ignorant and unskilled to make that happen, but had a number
of breakthroughs yesterday, and hopefully will get some bicubic patch code
cobbled together as a proof-of-concept.  Then it ought to be much smoother and
prettier.

> I processed the data (deviation from the average) and used triangles to
> make the plate.

I used the raw data, since there was no information indicating that the plate
was flat, and so it looks like it's vibrations in a stressed plate.

I'm going to give some thought to finding vibrational nodes and have the edges
flex freely using those as the true stationary points.

Given time, talent, inspiration, freedom from interruption, plenty of coffee,
and tips and helpful feedback from the helpful folks here in POV-Land.


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From: Bald Eagle
Subject: Re: Vibrating Plate WIP
Date: 7 Mar 2016 04:15:00
Message: <web.56dcff7b5a67670a5e7df57c0@news.povray.org>
So, I'm trying to work through in my head what the best way to model this is,
with the amplitudes and the times, and the measurement points, and the
intermediate control points of the patch.

I started to model the plate as an isosurface of interfering cosine waves, which
was humming along as smoothly as I could have hoped, and then my function
started throwing errors.

Once I commented out the additional parameters, it was fine.
Is there some upper limit to how much stuff you can stuff into a function?

############################################################################

#version 3.7;
global_settings { assumed_gamma 1.0 }

//------------------------------------------
// SDL for
// Bill Walker - 2016
//------------------------------------------

#include "colors.inc"
#include "debug.inc"
 Set_Debug (true)
#include "math.inc"
#include "TempGradient.inc"

light_source { <0, 50, -50>  color rgb <1, 1, 1>}


#declare Camera_Front = camera {
                            location  <0, 75, -1>
                            //right    x*image_width/image_height
                            look_at   <0, 0, 0>}


camera {Camera_Front}

#declare Y = 0;
#declare PW = 56.378/2;
#declare r=125;

// amplitudes based on 1st 150 points, max-min
#declare A4 = 0.007;
#declare A6 = 0.015;
#declare A2 = 0.006;
#declare A7 = 0.009;
#declare A10 = 0.009;
#declare A9 =  0.011;

#declare Point2  = <-00.9,   -0.106,  PW>;
#declare P2 = Point2.x;
#declare Point4  = < 50.0,   -0.037,  0>;
#declare P4 = Point4.x;
#declare Point6  = < 28.0,   0.048,  -PW>;
#declare P6 = Point6.x;
#declare Point7  = <-22.0,   -0.033,  -PW>;
#declare P7 = Point7.x;
#declare Point9  = <-50.0,   0.01,  -19.8>;
#declare P7 = Point9.x;
#declare Point10 = <-50.0,   0.075,  PW-21.9>;
#declare Z10 = PW - 21.9;
#declare P7 = Point10.x;

#declare Freq = 0.05;

isosurface{ //------------------------- "sombrero"
  function{ y -
   A2 * cos(sqrt(pow(x, 2) - (2*P2*x)  + pow(P2, 2)  + pow(z, 2) - (2*PW*z)  +
pow(PW, 2))*Freq*pi) +
   A4 * cos(sqrt(pow(x, 2) - (2*P4*x)  + pow(P4, 2)  + pow(z, 2) - (2*0*z)   +
pow(0, 2)) *Freq*pi) +
   A6 * cos(sqrt(pow(x, 2) - (2*P6*x)  + pow(P6, 2)  + pow(z, 2) - (2*-PW*z) +
pow(PW, 2))*Freq*pi) +
   A7 * cos(sqrt(pow(x, 2) - (2*P7*x)  + pow(P7, 2)  + pow(z, 2) - (2*-PW*z) +
pow(PW, 2))*Freq*pi) //+
  //A9 * cos(sqrt(pow(x, 2) - (2*P9*x)  + pow(P9, 2)  + pow(z, 2) + (2*19.8*z) +
pow(19.8, 2))*Freq*pi) +
  //A10 * cos(sqrt(pow(x, 2) - (2*P10*x) + pow(P10, 2) + pow(z, 2) - (2*Z10*z) +
pow(Z10, 2))*Freq*pi)
  }

  threshold 0
  contained_by{box{<-50, -1, -PW>, <50, 1, PW>}}

  texture{
    pigment{ TempGradient scale <1, 0.08, 1>}
    //normal { ripples 0.5 scale 0.125}
    //finish { phong 1}
  } // end of texture
  scale <1, 10, 1>
  rotate <0,0,0>
  translate <0,0,0>
} // end of isosurface ----------------


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From: clipka
Subject: Re: Vibrating Plate WIP
Date: 7 Mar 2016 09:35:11
Message: <56dd4b4f$1@news.povray.org>
Am 07.03.2016 um 05:11 schrieb Bald Eagle:

> I started to model the plate as an isosurface of interfering cosine waves, which
> was humming along as smoothly as I could have hoped, and then my function
> started throwing errors.

Can you elaborate? "throwing errors" is not a very precise description
of symptoms ;)

> Once I commented out the additional parameters, it was fine.
> Is there some upper limit to how much stuff you can stuff into a function?

There shouldn't be any.


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From: Bald Eagle
Subject: Re: Vibrating Plate WIP
Date: 7 Mar 2016 20:00:01
Message: <web.56dddcec5a67670a5e7df57c0@news.povray.org>
clipka <ano### [at] anonymousorg> wrote:

> Can you elaborate? "throwing errors" is not a very precise description
> of symptoms ;)

I tracked it down to a malfunction between the auditory sensors of the organic
keyboard operating device.  Somehow, it wasn't properly coupled to the LCD
output and was dropping data packets.   :|
Anyway, I got it to work, and it's interesting to see what a nice job the
isosurface does in showing the interference patterns of the vibrations, assuming
that the vibrations are simple harmonic oscillators.

Still need to think on how to "raise" the y-axis level of each vibrational
source to better model it, and then how to offset the phase according to the
frame_number.

Not sure how the real vibrational data ought to be propagated into the plate
aside from that - maybe run it through a fast Fourier transform and somehow
alter the changes in frequency and amplitude based on that....

yikes.  :O


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From: Stephen
Subject: Re: Vibrating Plate WIP
Date: 7 Mar 2016 22:54:27
Message: <56de06a3$1@news.povray.org>
On 3/7/2016 7:56 PM, Bald Eagle wrote:
> clipka <ano### [at] anonymousorg> wrote:
>
>> Can you elaborate? "throwing errors" is not a very precise description
>> of symptoms ;)
>
> I tracked it down to a malfunction between the auditory sensors of the organic
> keyboard operating device.  Somehow, it wasn't properly coupled to the LCD
> output and was dropping data packets.   :|

Cotton buds, work wonders. ;-)


> Anyway, I got it to work, and it's interesting to see what a nice job the
> isosurface does in showing the interference patterns of the vibrations, assuming
> that the vibrations are simple harmonic oscillators.
>
> Still need to think on how to "raise" the y-axis level of each vibrational
> source to better model it,

Am I missing something here?
I has a similar problem as the Modeller I use (Bishop3D this time not 
blender) only uses 3 decimal places. So I multiplied the data by a 
thousand and reduced the scale of the plane appropriately.

> and then how to offset the phase according to the
> frame_number.
>

You have lost me there.

> Not sure how the real vibrational data ought to be propagated into the plate
> aside from that - maybe run it through a fast Fourier transform and somehow
> alter the changes in frequency and amplitude based on that....
>

Can you trust the data enough to extrapolate?

> yikes.  :O
>

Double yikes and a "Jinges and Crivens." thrown in.


-- 

Regards
     Stephen


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From: Bald Eagle
Subject: Re: Vibrating Plate WIP
Date: 8 Mar 2016 00:30:03
Message: <web.56de1c9a5a67670a5e7df57c0@news.povray.org>
Stephen <mca### [at] aolcom> wrote:

> > Still need to think on how to "raise" the y-axis level of each vibrational
> > source to better model it,
>
> Am I missing something here?
> I has a similar problem as the Modeller I use (Bishop3D this time not
> blender) only uses 3 decimal places. So I multiplied the data by a
> thousand and reduced the scale of the plane appropriately.

I mean in the isosurface formula.  When I plot out all the data in Excel, I see
that the mean y-values for all the different points vary.   I'm not sure how to
include the height differences of the points in my function.

> > and then how to offset the phase according to the
> > frame_number.
> >
>
> You have lost me there.

The isosurface is at present static.  I want to change the phase of my cosine
waves in the function, based on frame_number.   That way the waves ripple
outwards from the data points.

> > Not sure how the real vibrational data ought to be propagated into the plate
> > aside from that - maybe run it through a fast Fourier transform and somehow
> > alter the changes in frequency and amplitude based on that....
> >
>
> Can you trust the data enough to extrapolate?

I haven't really thought it that far out.
This is, after all, a problem posed by the OP.   It just caught my interest.

OK - back to interpolating the control points for my 3x3 bicubic patch model.
16 data points, 128 interpolated control points, 144 control points altogether.
 :D


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