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:
```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:
```

Attachments:

Preview of image 'invisibilityshield_front.jpg'

 From: Dave Blandston Subject: Re: Invisibility Shield Date: 25 Nov 2020 09:30:01 Message:
```And a top view:
```

Attachments:

Preview of image 'invisibilityshield_top.jpg'

 From: Kenneth Subject: Re: Invisibility Shield Date: 25 Nov 2020 19:55:06 Message:
```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?
```
 From: Dave Blandston Subject: Re: Invisibility Shield Date: 25 Nov 2020 20:30:07 Message:
```"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 Thickness = .03;
#local Angle = 60;

#local ShieldCutout = object {
#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
```
 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
```

Attachments:

Preview of image 'db_invisibility_shield.png'

 From: Dave Blandston Subject: Re: Invisibility Shield Date: 26 Nov 2020 09:40:01 Message:
```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
```
 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
```
 From: Dave Blandston Subject: Re: Invisibility Shield Date: 27 Nov 2020 09:15:00 Message:
```Thomas de Groot <tho### [at] degrootorg> wrote:
>
> I just used your code 'as is'. :-)
>
> --
> Thomas

Cool!
```
 From: BayashiPascal Subject: Re: Invisibility Shield Date: 28 Nov 2020 02:20:08 Message:
```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:
```
 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.
```