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From: clipka
Subject: Re: Vibrating Plate WIP
Date: 8 Mar 2016 03:50:42
Message: <56de9262$1@news.povray.org>
Am 07.03.2016 um 20:56 schrieb Bald Eagle:
> 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.   :|

Normally it's the visual sensors that you couple to the LCD, not the
auditory ones. Anoter OKOD malfunction?
But yeah, accidental OKOD disconnects can be a real pain in the rear
orifice ;)


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From: Stephen
Subject: Re: Vibrating Plate WIP
Date: 8 Mar 2016 06:17:14
Message: <56deb4ba$1@news.povray.org>
On 3/8/2016 12:28 AM, Bald Eagle wrote:
> 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.
>

It slipped my mind that you were using isosurfaces at this point.
Would it not be something like:
Cos(Θ + 2*pi * {[final_frame - initial_frame]/ 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....
>>>
>>
>> Can you trust the data enough to extrapolate?
>
> I haven't really thought it that far out.

It was the first thing I did. :-)

> This is, after all, a problem posed by the OP.   It just caught my interest.
>

It caught mine too.

> 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

Good luck. :-)
IIRC Moray had a way of joining bicubic patchs.
I just downloaded Moray and had a look. The joining control points are 
all calculated internally and the patches are bound in a union. It looks 
like Lutz just used a simple function, possibly the average of the 
points on either side.


-- 

Regards
     Stephen


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From: Stephen
Subject: Re: Vibrating Plate WIP
Date: 8 Mar 2016 07:12:42
Message: <56dec1ba$1@news.povray.org>
On 3/8/2016 11:17 AM, Stephen wrote:
>> 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
>
> Good luck. :-)
> IIRC Moray had a way of joining bicubic patchs.

I don't know if this will help you. This is a couple of bicubic patches 
that make a cylinder of radius 1. Note that the Y value is 4/3 and in 
Moray, Z is up. (Please don't restart the Maths Vs Engineering, flame 
war. ;-) )



union { // BezPtch001
   object {
     bicubic_patch { type 1 flatness 0.0100 u_steps 3 v_steps 3,
       <-1.000000, 0.000000, 0.000000>, <-1.000000, -1.333333, 
0.000000>, <1.000000, -1.333333, 0.000000>, <1.000000, 0.000000, 0.000000>,
       <-1.000000, 0.000000, 2.000000>, <-1.000000, -1.333333, 
2.000000>, <1.000000, -1.333333, 2.000000>, <1.000000, 0.000000, 2.000000>,
       <-1.000000, 0.000000, 4.000000>, <-1.000000, -1.333333, 
4.000000>, <1.000000, -1.333333, 4.000000>, <1.000000, 0.000000, 4.000000>,
       <-1.000000, 0.000000, 6.000000>, <-1.000000, -1.333333, 
6.000000>, <1.000000, -1.333333, 6.000000>, <1.000000, 0.000000, 6.000000>
     }
   }
   object {
     bicubic_patch { type 1 flatness 0.0100 u_steps 3 v_steps 3,
       <1.000000, 0.000000, 0.000000>, <1.000000, 1.333333, 0.000000>, 
<-1.000000, 1.333330, 0.000000>, <-1.000000, 0.000000, 0.000000>,
       <1.000000, 0.000000, 2.000000>, <1.000000, 1.333333, 2.000000>, 
<-1.000000, 1.333330, 2.000000>, <-1.000000, 0.000000, 2.000000>,
       <1.000000, 0.000000, 4.000000>, <1.000000, 1.333333, 4.000000>, 
<-1.000000, 1.333330, 4.000000>, <-1.000000, 0.000000, 4.000000>,
       <1.000000, 0.000000, 6.000000>, <1.000000, 1.333333, 6.000000>, 
<-1.000000, 1.333330, 6.000000>, <-1.000000, 0.000000, 6.000000>
     }
   }

}


-- 

Regards
     Stephen


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From: Thomas de Groot
Subject: Re: Vibrating Plate WIP
Date: 8 Mar 2016 07:18:35
Message: <56dec31b$1@news.povray.org>
On 8-3-2016 13:12, Stephen wrote:
> I don't know if this will help you. This is a couple of bicubic patches
> that make a cylinder of radius 1. Note that the Y value is 4/3 and in
> Moray, Z is up. (Please don't restart the Maths Vs Engineering, flame
> war. ;-) )

scale <1,1,-1>
rotate 90*x

:-)


-- 
Thomas


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From: Bald Eagle
Subject: Re: Vibrating Plate WIP
Date: 8 Mar 2016 07:25:00
Message: <web.56dec3a45a67670a5e7df57c0@news.povray.org>
clipka <ano### [at] anonymousorg> wrote:


Parse error.
Expected actual Statement but found misinterpretation instead.
:D  ;)

The auditory sensors were not the location of the malfunction.
Therefore, they need not be coupled to the LCD.
It was a malfunction BETWEEN the auditory sensors.

I'm sure that a fatigued RAID array of optical drives didn't help things.


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From: Bald Eagle
Subject: Re: Vibrating Plate WIP
Date: 8 Mar 2016 07:40:01
Message: <web.56dec7905a67670a5e7df57c0@news.povray.org>
The problem I have / had was not joining the patches together - I worked that
out last week with the 4 bicubic patches.

What I'm trying to do now is essentially take the corners of the patches, set
those as the data points, and interpolate the first and last rows to get the 2
intermediate control points of those rows, then run through all of the columns
to set all of the control points in rows 2 and 3.

I got the interpolation all worked out (so I thought), put together 9 patches,
linked all the corners and edges, and coded the whole interpolation of the grid.

Somehow, somewhere, the interpolation doesn't like the data.
I think it's the negative numbers, since my 9 patches are centered on the
origin.
The original javascript outputs, and inputs from SVG - so there aren't any
negative screen coordinates.

Looks like today I might be debugging THAT today to see where it goes
fundamentally wrong.

I can post in scene-files if anyone would like to look and help pick it apart.

or, actually,
Original javascript is embedded in an SVG here:
https://www.particleincell.com/wp-content/uploads/2012/06/circles.svg


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From: Stephen
Subject: Re: Vibrating Plate WIP
Date: 8 Mar 2016 08:09:25
Message: <56decf05$1@news.povray.org>
On 3/8/2016 12:18 PM, Thomas de Groot wrote:
> On 8-3-2016 13:12, Stephen wrote:
>> I don't know if this will help you. This is a couple of bicubic patches
>> that make a cylinder of radius 1. Note that the Y value is 4/3 and in
>> Moray, Z is up. (Please don't restart the Maths Vs Engineering, flame
>> war. ;-) )
>
> scale <1,1,-1>
> rotate 90*x
>
> :-)
>
>
You've got a long memory. ;-)

It was strange looking at Pov 3.1 again. It must be 10 years since I 
last used it regularly.

Then I thought about running the benchmark on 3.1
There is none but I came across this:

http://www.verycomputer.com/10_7d4a92f29cb0df5d_1.htm

+A +Ifish13.pov +Ofish.tga +W720 +H486
It took the author 70 hours to run it.
On my i7 machine it took 13 seconds with 3.1g and 3 seconds with 3.7

:-D

-- 

Regards
     Stephen


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From: Bald Eagle
Subject: Re: Vibrating Plate WIP
Date: 8 Mar 2016 08:45:00
Message: <web.56ded7545a67670a5e7df57c0@news.povray.org>
OK, upon further investigation, the interpolation is seriously cracked.

Initially I played around with the starting data set in the SVG,
and then when the interpolated patches started wigging out, I went back and
moved the data points around a bit and moved the camera to look at the spline in
z, y, and z.   It _looked_ ok.

The following are interpolated splines for:

#declare DataSet = array [5]{
array[10]{<-40, 0, 0>, <0,0,0>, <0,0,0>, <-30, 0, 0>, <0,0,0>, <0,0,0>, <-20, 0,
0>, <0,0,0>, <0,0,0>, <-10, 0, 0>},
array[10]{<10, 0, 0>, <0,0,0>, <0,0,0>, <20, 0, 0>, <0,0,0>, <0,0,0>, <30, 0,
0>, <0,0,0>, <0,0,0>, <40, 0, 0>},

array[10]{<20, 20, 0>, <0,0,0>, <0,0,0>, <30, 30, 0>, <0,0,0>, <0,0,0>, <40, 20,
0>, <0,0,0>, <0,0,0>, <50, 25, 0>}

array[10]{<-10, 5, 0>, <0,0,0>, <0,0,0>, <-20, 5, 0>, <0,0,0>, <0,0,0>, <-30, 5,
0>, <0,0,0>, <0,0,0>, <-40, 5, 0>},
array[10]{<40, 5, 0>, <0,0,0>, <0,0,0>, <30, 5, 0>, <0,0,0>, <0,0,0>, <20, 5,
0>, <0,0,0>, <0,0,0>, <10, 5, 0>}
};

As you can see, I took the top 2 splines and just reordered the data from
beginning to end (and shifted y by 5).   Not looking good.
Someone please page Jerome.  LeForgeron is needed with his mathematical / c++
cape, to bend this Bezier back in line!  Er, I mean curve!  No, wait - line.
:|


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Attachments:
Download 'retrobeziernegativeproblem.png' (20 KB)

Preview of image 'retrobeziernegativeproblem.png'
retrobeziernegativeproblem.png


 

From: Stephen
Subject: Re: Vibrating Plate WIP
Date: 8 Mar 2016 08:59:31
Message: <56dedac3@news.povray.org>
On 3/8/2016 1:44 PM, Bald Eagle wrote:
> Someone please page Jerome.  LeForgeron is needed

You are not asking me?
<Rolls on the floor hysterically.>

;-)

-- 

Regards
     Stephen


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From: Stephen
Subject: Re: Vibrating Plate WIP
Date: 8 Mar 2016 09:16:07
Message: <56dedea7$1@news.povray.org>
Just had a thought. Put aside the original data and use some made up 
data that you know the curve. Then come back to the original data when 
you are happy with your curves.

But before that. Take a raw egg and using a sharp implement pierce both 
ends of the egg. Place the large end in your mouth and inhale. ;-)


-- 

Regards
     Stephen


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