Hi Experts,

I am looking at the suitability of POV-Ray for LED luminaries design, simulation
and measurement of light intensity/uniformity of distribution. Here are the list
of things I am looking for:

1.Ability to model different (and multiple) high bright LEDs that are used in
lighting applications in different geometric arrangement (mean different
numbers and spatial configuration). Alternatively, convert the models that are
available in other formats like IES, ProSource to use with POV-Ray.

2.Create and model different type of reflectors/reflecting surfaces (of both
geometrical and optical characteristics) and diffusers.

3.Study/Measure the intensity levels, distribution and chromacity.

BTW, I already looked at the Colin's posting on the intesity mapping. I am
looking at Lightsys by Jaime Vives Piqueres.

Appreciate your help.

Kanak

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> Hi Experts,
> 
> I am looking at the suitability of POV-Ray for LED luminaries design, simulation
> and measurement of light intensity/uniformity of distribution. Here are the list
> of things I am looking for:
> 
> 1.Ability to model different (and multiple) high bright LEDs that are used in
> lighting applications in different geometric arrangement (mean different
> numbers and spatial configuration). Alternatively, convert the models that are
> available in other formats like IES, ProSource to use with POV-Ray.
> 
> 2.Create and model different type of reflectors/reflecting surfaces (of both
> geometrical and optical characteristics) and diffusers.
> 
> 3.Study/Measure the intensity levels, distribution and chromacity.
> 
> BTW, I already looked at the Colin's posting on the intesity mapping. I am
> looking at Lightsys by Jaime Vives Piqueres.
> 
> Appreciate your help.
> 
> Kanak
> 
> 
I don't think that you can get absolutely exact light distrubution, but...

You can model reflectors and lences of just about any shape imaginable. 
Then, using photons maping and a surface acting as a screen, get a good 
idea of the light distribution.
As long as the shapes, reflective values, tints, ior and dispersion 
values are a reflection if the actual ones, your results should be good.

You can also use medias to show the spacial, volumetric, distribution of 
the light.

To test various spacial arrangments of multiple lights, you only need to 
place individual lights in that arrangment, including the opaques parts.

If you are ready to use a beta version, you can use the 3.7 betas that 
can output high dynamic range images. That way, you are no longer 
limited by the dynamic range of the common graphic formats.

For the chromaticity, as the output is RGB encoded, the chromaticity 
study is prety limited. It can only be simulated using dispersion with 
refraction. It gives an approximation of a black body, at least, that's 
my impression.

You are looking at the right places, both are good resources. Lightsys 
have IES profils, and others.



Alain

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> Hi Experts,
> 
> I am looking at the suitability of POV-Ray for LED luminaries design, 
> simulation and measurement of light intensity/uniformity of distribution.
>  Here are the list of things I am looking for:
> 

   I think it would be very cumbersome to do such things in POV-Ray, if
possible at all, mainly because it was never designed to be an analytic
tool, but an artistic tool.

   Regarding your specific points:

   1) POV-Ray light sources don't support spatial distribution models (a la
IES).

   2) You will have to model very accurate fixtures with very accurate
materials and use photons, and then hope the result would be accurate enough.

   3) If you read the thread started by Colin, the suggestions there are the
only ones I can think of... as I said before, perhaps possible, but not very
direct or practical.

   Regards,

--
Jaime

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Thanks Alain and Jaime for your quick and detailed response. One of the
motivations for my question is the result posted in this URL:

http://www.donzoptix.co.uk/POVZEMAX/CaliZMPV.html

Kanak

Post a reply to this message

> Thanks Alain and Jaime for your quick and detailed response. One of the
> motivations for my question is the result posted in this URL:
> 
> http://www.donzoptix.co.uk/POVZEMAX/CaliZMPV.html
> 
> Kanak
> 
> 
> 
> 
> 
OK
What was done there is to project the light on a plane, render that 
plane, then use the resulting image as the source to create a hight_field.

Altough POV-Ray was not created to do such light propagation analysis, 
it can be done in a few steps.
It's one of those cases when the possibilities of a tool FAR excede the 
purpose for whitch it was created.


Alain

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Alain <aze### [at] qwertyorg> wrote:

> > Thanks Alain and Jaime for your quick and detailed response. One of the
> > motivations for my question is the result posted in this URL:
> >
> > http://www.donzoptix.co.uk/POVZEMAX/CaliZMPV.html
> >
> > Kanak
> >
> >
> >
> >
> >
> OK
> What was done there is to project the light on a plane, render that
> plane, then use the resulting image as the source to create a hight_field.
>
> Altough POV-Ray was not created to do such light propagation analysis,
> it can be done in a few steps.
> It's one of those cases when the possibilities of a tool FAR excede the
> purpose for whitch it was created.
>
>
> Alain

Thanks Alain. Will post here if I make any progress with this.

Regards,
Kanak

Post a reply to this message

> I am looking at the suitability of POV-Ray for LED luminaries design, 
> simulation
> and measurement of light intensity/uniformity of distribution. Here are 
> the list
> of things I am looking for:
>
> 1.Ability to model different (and multiple) high bright LEDs that are used 
> in
> lighting applications in different geometric arrangement (mean different
> numbers and spatial configuration). Alternatively, convert the models that 
> are
> available in other formats like IES, ProSource to use with POV-Ray.
>
> 2.Create and model different type of reflectors/reflecting surfaces (of 
> both
> geometrical and optical characteristics) and diffusers.
>
> 3.Study/Measure the intensity levels, distribution and chromacity.

IMO you are really going to be struggling with POV to get any realistic 
output.  POV was not designed to be a physically correct simulator of light 
rays, there are too many "gotchas" to look out for, and finding realistic 
material data to work with POV will be hard.

You are far better off (not financially!) using a program like ASAP which 
has been specifically designed for these types of simulations (this is what 
we use for simulating LEDs and optical stacks):

http://www.breault.com/software/asap.php

I'm not saying it's impossible in POV, just that it's not really the best 
tool for the job.

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