http://www.youtube.com/watch?v=gJDsju0pSqQ

I did this lenticular image in POV-Ray, but I didn't have any lenticular sheets
yet to print it out just yet. I was anxious to see what it might look like, so
I figured out a way of doing it virtually in POV-Ray. I took the image that was
to be my lenticular print out and applied it as a texture map on a square. Then
I put a model of an array of half-cylinder lenses in front of the square in
POV-Ray to "play back" the lenticular image. I wasn't sure if this would work,
but it did. When I get the sheets, I'll print it out for real.

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"Captain Tylor" <nomail@nomail> wrote:
> http://www.youtube.com/watch?v=gJDsju0pSqQ
>
> I did this lenticular image in POV-Ray, but I didn't have any lenticular sheets
> yet to print it out just yet. I was anxious to see what it might look like, so
> I figured out a way of doing it virtually in POV-Ray. I took the image that was
> to be my lenticular print out and applied it as a texture map on a square. Then
> I put a model of an array of half-cylinder lenses in front of the square in
> POV-Ray to "play back" the lenticular image. I wasn't sure if this would work,
> but it did. When I get the sheets, I'll print it out for real.

My, this is...!

Amazing!

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I want one :)

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"Captain Tylor" <nomail@nomail> wrote:
> http://www.youtube.com/watch?v=gJDsju0pSqQ
>
> I did this lenticular image in POV-Ray, but I didn't have any lenticular sheets
> yet to print it out just yet. I was anxious to see what it might look like, so
> I figured out a way of doing it virtually in POV-Ray. I took the image that was
> to be my lenticular print out and applied it as a texture map on a square. Then
> I put a model of an array of half-cylinder lenses in front of the square in
> POV-Ray to "play back" the lenticular image. I wasn't sure if this would work,
> but it did. When I get the sheets, I'll print it out for real.


I had never thought on this particular effect.
Cool!

--
Carlo

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That's just plain fascinating! What a great experiment to try. I've been
thinking lately of the lenticular process as well (although not in relation to
reproducing the effect *IN* POV-Ray--that never occurred to me!) An excellent
way to pre-visualize the technique. Thanks for the inspiration;

And since lenticular effects depend on the viewer-to-print distance, POV-Ray can
even be used to test *that*.

Question 1:
What camera 'angle' are you using that best matches our eyeballs?

Question 2:
What IOR are you using for the lenticular 'screen'?

Question 3:
Do such screens use 'cylinders' (half-cylinders?) for lenses, or triangular
prism-like shapes? I guess I need to bone up on the actual process; haven't
explored this in detail for a long time.

KW

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Thanks for the replies.

Here's the camera set-up I was using:

camera {
  cylinder 4
  location <0,0,-4>
  right 2*x
  up 4*y
  look_at  <0,0,0>
  angle 37.4
}

Since the horizontal perspective of the image is being provided by the lenses, I
needed to use a camera that was orthagraphic in the horizontal direction and had
perspective in the vertical direction.  The cylinder camera provided the
solution I was after.

The ior I was using was 1.49 for acrylic, but I might have to tweak that when I
know better exatly what material I'm working with.

The objects in my scene extend from 0.0 pov-ray units to 0.6 pov-ray units to
the back of the view and 1 pov-ray unit horizontally and 1 pov-ray unit
vertically.

Most suppliers of lenticular sheets make them with cylindrical lenses. I'm not
sure if there are any that make them with the triangular lenses.

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"Captain Tylor" <nomail@nomail> wrote:
> Thanks for the replies.
>
> Here's the camera set-up I was using:
>
> camera {
>   cylinder 4
>   location <0,0,-4>
>   right 2*x
>   up 4*y
>   look_at  <0,0,0>
>   angle 37.4
> }
>
> Since the horizontal perspective of the image is being provided by the lenses, I
> needed to use a camera that was orthagraphic in the horizontal direction and had
> perspective in the vertical direction.  The cylinder camera provided the
> solution I was after.

Hmm, I may be confused here. I guess there are TWO cameras involved--one for
making the 'print,' and one for looking at the final result.  (Do I have that
right?) Or actually three cameras--two for making the stereo pairs, and one for
viewing it. Is your cylindrical camera for 'making' the print(s), or for viewing
the final lenticular object in the animation?

KW

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"Captain Tylor" <nomail@nomail> wrote:
> http://www.youtube.com/watch?v=gJDsju0pSqQ
>
> I did this lenticular image in POV-Ray, [...]

I like, very much, as it replicates the off-axis visual artefacts too!
If presented with this challenge, I would have been tempted to cheat and use
trace() to make a portal into another scene from the 'print'.

Can you do holograms? ;oP

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"Captain Tylor" <nomail@nomail> wrote:
> http://www.youtube.com/watch?v=gJDsju0pSqQ
>
> I did this lenticular image in POV-Ray.

Could this principle be extended to two axes, using hemi-spherical lenticular
elements (and in real life, strong back-lighting, because POV-Ray doesn't do
refracted intensity)?

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I used the cylindrical camera to render the image that was applied to the
square.

I did the animation in another pov-ray file with a regular perspective camera.

Yes, this can be extended to use hemispherical lenses, which I've already done
in a previous project, seen below.

http://holographyforum.org/phpBB2/viewtopic.php?f=6&t=4427&p=35781&hilit=integrams#p35781

I'm not sure what you mean about the strong backlighting.

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