POV-Ray : Newsgroups : povray.binaries.images : Invisibility Shield Server Time: 28 Jan 2021 15:52:08 GMT
  Invisibility Shield (Message 1 to 10 of 10)  
From: Dave Blandston
Subject: Invisibility Shield
Date: 25 Nov 2020 09:25:01
Message: <web.5fbe22c770cd1d9779416a1f0@news.povray.org>
Hi Folks,

After watching this video https://www.youtube.com/watch?v=G93bju1qCSI I
endeavored to make a POV version and it worked fairly well.

Here's a front view:


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From: Dave Blandston
Subject: Re: Invisibility Shield
Date: 25 Nov 2020 09:30:01
Message: <web.5fbe23283ff595d979416a1f0@news.povray.org>
And a top view:


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From: Kenneth
Subject: Re: Invisibility Shield
Date: 25 Nov 2020 19:55:06
Message: <web.5fbeb5bd3ff595d9d98418910@news.povray.org>
So the effect even works in POV-ray; fascinating.

For your shield, are the 'lenticular lens' shapes made with real geometry, or by
using normals on a smooth curved surface?


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From: Dave Blandston
Subject: Re: Invisibility Shield
Date: 25 Nov 2020 20:30:07
Message: <web.5fbebe9b3ff595d979416a1f0@news.povray.org>
"Kenneth" <kdw### [at] gmailcom> wrote:
> So the effect even works in POV-ray; fascinating.
>
> For your shield, are the 'lenticular lens' shapes made with real geometry, or by
> using normals on a smooth curved surface?



I used a CSG difference so there wouldn't be any internal or coincident
surfaces. I don't know if that would have made a difference or not.



#local ShieldRadius = 1;
#local Thickness = .03;
#local Angle = 60;

#local LensRadius = .002;

#local ShieldCutout = object {
   #local R0 = ShieldRadius - LensRadius;
   #local DeltaTheta = degrees (asin ((LensRadius / 2) / R0)) * 4;
   difference {
      cylinder {<0, -.1, 0>, <0, 1.1, 0>, ShieldRadius + .2}
      cylinder {<0, -.2, 0>, <0, 1.2, 0>, R0}
      #for (Theta, 180 + Angle, 360 - Angle, DeltaTheta)
         cylinder {<R0, -.2, 0>, <R0, 1.2, 0>, LensRadius rotate -Theta * y}
      #end //#for
   } //difference
} //object

#local Shield = object {
   intersection {
      difference {
         cylinder {<0, 0, 0>, <0, 1, 0>, ShieldRadius + .1}
         cylinder {<0, -.1, 0>, <0, 1.1, 0>, ShieldRadius - Thickness}
         object {ShieldCutout}
      } //difference
      plane {z, 0 rotate Angle * y}
      plane {z, 0 rotate -Angle * y}
   } //intersection
   material {Glass}
   photons {target reflection on refraction on collect off}
} //object


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From: Thomas de Groot
Subject: Re: Invisibility Shield
Date: 26 Nov 2020 08:19:06
Message: <5fbf64fa$1@news.povray.org>
Perfect!

[Whaaaaa....! Who stole my ball....??!?]

-- 
Thomas


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From: Dave Blandston
Subject: Re: Invisibility Shield
Date: 26 Nov 2020 09:40:01
Message: <web.5fbf76ef3ff595d979416a1f0@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
> Perfect!
>
> [Whaaaaa....! Who stole my ball....??!?]
>
> --
> Thomas



Fantastic - did you use normals to simulate the lenses? Using geometry might be
a limitation because of the huge number of required lenses. Also, did you change
the shape of the shield from circular to oval or parabolic? I'm wondering if
that would make a difference.

Have a great day!

Kind regards,
Dave Blandston


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From: Thomas de Groot
Subject: Re: Invisibility Shield
Date: 27 Nov 2020 07:31:03
Message: <5fc0ab37@news.povray.org>
Op 26/11/2020 om 10:35 schreef Dave Blandston:
> Fantastic - did you use normals to simulate the lenses? Using geometry might be
> a limitation because of the huge number of required lenses. Also, did you change
> the shape of the shield from circular to oval or parabolic? I'm wondering if
> that would make a difference.
> 

I just used your code 'as is'. :-)

-- 
Thomas


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From: Dave Blandston
Subject: Re: Invisibility Shield
Date: 27 Nov 2020 09:15:00
Message: <web.5fc0c2d83ff595d979416a1f0@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
>
> I just used your code 'as is'. :-)
>
> --
> Thomas


Cool!


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From: BayashiPascal
Subject: Re: Invisibility Shield
Date: 28 Nov 2020 02:20:08
Message: <web.5fc1b3523ff595d92ce8b2430@news.povray.org>
That's very interesting. Thanks for sharing.


"Dave Blandston" <nomail@nomail> wrote:
> Hi Folks,
>
> After watching this video https://www.youtube.com/watch?v=G93bju1qCSI I
> endeavored to make a POV version and it worked fairly well.
>
> Here's a front view:


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From: William F Pokorny
Subject: Re: Invisibility Shield
Date: 28 Nov 2020 15:41:43
Message: <5fc26fb7$1@news.povray.org>
On 11/25/20 4:24 AM, Dave Blandston wrote:
> Hi Folks,
> 
> After watching this video https://www.youtube.com/watch?v=G93bju1qCSI I
> endeavored to make a POV version and it worked fairly well.
> 
> Here's a front view:
> 
Neat! :-)

Bill P.


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