POV-Ray : Newsgroups : povray.general : Lens simulation -> texture ? Server Time
1 Aug 2024 10:11:54 EDT (-0400)
  Lens simulation -> texture ? (Message 1 to 6 of 6)  
From: Simon Dyer
Subject: Lens simulation -> texture ?
Date: 5 Dec 2005 06:03:28
Message: <43941e80@news.povray.org>
I'm trying to simulate a lens as a texture in plastic, similar to the effect
of a lenticular or fresnel lens.
PovRay seemed to make sense to simulate the plastic, but oh what a learning
curve.

Wondered if anyone could point me to a texture library or tutorial to help
in this endeavour.

The plan is to design the shape ( thin plastic about 2mm thick ) and add an
underside repeating pattern texture that will let light arriving at the
normal through from above but not light that hits at a tight angle.  Once
I've simulated this in PovRay and proven it, the texture will be used in the
CAD-CAM thats going to tooling for the injection moulding process.  Many of
the engineering packages cannot do real ray tracing so they cannot simulate
the lens effect and I'm stuck .

Any help or pointers would really be appreciated.

--


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From: Alain
Subject: Re: Lens simulation -> texture ?
Date: 5 Dec 2005 17:10:04
Message: <4394babc$1@news.povray.org>
Simon Dyer nous apporta ses lumieres en ce 2005-12-05 06:03:
> I'm trying to simulate a lens as a texture in plastic, similar to the effect
> of a lenticular or fresnel lens.
> PovRay seemed to make sense to simulate the plastic, but oh what a learning
> curve.
> 
> Wondered if anyone could point me to a texture library or tutorial to help
> in this endeavour.
> 
> The plan is to design the shape ( thin plastic about 2mm thick ) and add an
> underside repeating pattern texture that will let light arriving at the
> normal through from above but not light that hits at a tight angle.  Once
> I've simulated this in PovRay and proven it, the texture will be used in the
> CAD-CAM thats going to tooling for the injection moulding process.  Many of
> the engineering packages cannot do real ray tracing so they cannot simulate
> the lens effect and I'm stuck .
> 
> Any help or pointers would really be appreciated.
> 
> --
> 
> 
> 
My first bet would be to use the onion pattern as my normal. You may need to scale it
down some.

-- 
Alain
-------------------------------------------------
Judaism: Why does this shit always happen to us?


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From: PM 2Ring
Subject: Re: Lens simulation -> texture ?
Date: 9 Dec 2005 08:10:00
Message: <web.43998139c818c7d5e47fda940@news.povray.org>
"Simon Dyer" <sim### [at] paradisenetnz> wrote:
> I'm trying to simulate a lens as a texture in plastic, similar to the effect
> of a lenticular or fresnel lens.

I don't think I've ever seen a fresnel lens done in POV. I did the basic
calculations for a 'spheric' fresnel a few years ago... they shouldn't be
too hard to find. I'll have to give it a go tomorrow.

> PovRay seemed to make sense to simulate the plastic, but oh what a learning
> curve.

Yes, but at least you have these forums to help ease that learning curve.

> Wondered if anyone could point me to a texture library or tutorial to help
> in this endeavour.

I only know the photons tutorial & example scene in the POV docs, but there
are a few people around who use POV for optical design work.

> The plan is to design the shape ( thin plastic about 2mm thick ) and add an
> underside repeating pattern texture that will let light arriving at the
> normal through from above but not light that hits at a tight angle.  Once
> I've simulated this in PovRay and proven it, the texture will be used in the
> CAD-CAM thats going to tooling for the injection moulding process.  Many of
> the engineering packages cannot do real ray tracing so they cannot simulate
> the lens effect and I'm stuck .

Sounds interesting.


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From: PM 2Ring
Subject: Re: Lens simulation -> texture ?
Date: 9 Dec 2005 08:10:01
Message: <web.439981fbc818c7d5e47fda940@news.povray.org>
Alain <ele### [at] netscapenet> wrote:
> Simon Dyer nous apporta ses lumieres en ce 2005-12-05 06:03:
> > I'm trying to simulate a lens as a texture in plastic, similar to the effect
> > of a lenticular or fresnel lens.

> My first bet would be to use the onion pattern as my normal. You may need to scale
it down some.

I don't think normals are physically accurate enough for this job, Alain.
And the basic onion pattern won't give the proper surface gradients anyway.


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From: Simon Dyer
Subject: Re: Lens simulation -> texture ?
Date: 9 Dec 2005 17:17:36
Message: <439a0280@news.povray.org>
If you want to see my first attempt, see "green photons render" in
povray.binaries.images.

"Simon Dyer" <sim### [at] paradisenetnz> wrote in message
news:43941e80@news.povray.org...
> I'm trying to simulate a lens as a texture in plastic, similar to the
effect
> of a lenticular or fresnel lens.
> PovRay seemed to make sense to simulate the plastic, but oh what a
learning
> curve.
>
> Wondered if anyone could point me to a texture library or tutorial to help
> in this endeavour.
>
> The plan is to design the shape ( thin plastic about 2mm thick ) and add
an
> underside repeating pattern texture that will let light arriving at the
> normal through from above but not light that hits at a tight angle.  Once
> I've simulated this in PovRay and proven it, the texture will be used in
the
> CAD-CAM thats going to tooling for the injection moulding process.  Many
of
> the engineering packages cannot do real ray tracing so they cannot
simulate
> the lens effect and I'm stuck .
>
> Any help or pointers would really be appreciated.
>
> --
>
>
>


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From: Simon Dyer
Subject: Re: Lens simulation -> texture ?
Date: 10 Dec 2005 17:09:53
Message: <439b5231@news.povray.org>
Lets push this a bit - I read somewhere here how Povray could be used to
calculate distances for us - could we get photons or rays to design each
'pixel' of  fresnel lens/lenticular to design a flat lens for a particular
purpose.  For example, provide the start and target for a light path to take
through a refractive medium, and have that medium defined by povray?

"Simon Dyer" <sim### [at] paradisenetnz> wrote in message
news:439a0280@news.povray.org...
> If you want to see my first attempt, see "green photons render" in
> povray.binaries.images.
>
> "Simon Dyer" <sim### [at] paradisenetnz> wrote in message
> news:43941e80@news.povray.org...
> > I'm trying to simulate a lens as a texture in plastic, similar to the
> effect
> > of a lenticular or fresnel lens.
> > PovRay seemed to make sense to simulate the plastic, but oh what a
> learning
> > curve.
> >
> > Wondered if anyone could point me to a texture library or tutorial to
help
> > in this endeavour.
> >
> > The plan is to design the shape ( thin plastic about 2mm thick ) and add
> an
> > underside repeating pattern texture that will let light arriving at the
> > normal through from above but not light that hits at a tight angle.
Once
> > I've simulated this in PovRay and proven it, the texture will be used in
> the
> > CAD-CAM thats going to tooling for the injection moulding process.  Many
> of
> > the engineering packages cannot do real ray tracing so they cannot
> simulate
> > the lens effect and I'm stuck .
> >
> > Any help or pointers would really be appreciated.
> >
> > --
> >
> >
> >
>
>


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