Hello everyone!

My field of research makes it necessary to build site-specific propagation
models for indoor wireless communication. Unfortunately - to my knowledge - no
open source raytracing engine currently exists.

Would it be possible to use POV-Ray to predict for example signal strength/delay
for an indoor scenario? If not, what would be necessary to achieve this?

Thank you all for your ideas!

Cheers,
Daniel

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Am 16.01.2014 08:31, schrieb pfefferk:
> Hello everyone!
>
> My field of research makes it necessary to build site-specific propagation
> models for indoor wireless communication. Unfortunately - to my knowledge - no
> open source raytracing engine currently exists.
>
> Would it be possible to use POV-Ray to predict for example signal strength/delay
> for an indoor scenario? If not, what would be necessary to achieve this?

I suspect that at the frequencies involved, the wavelike nature of the 
electromagnetic radiation becomes too much of an issue to simulate its 
propagation by means of raytracing. If that is the case, then POV-Ray is 
a poor starting point for what you're trying to achieve.

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> Am 16.01.2014 08:31, schrieb pfefferk:
>> Hello everyone!
>>
>> My field of research makes it necessary to build site-specific
>> propagation
>> models for indoor wireless communication. Unfortunately - to my
>> knowledge - no
>> open source raytracing engine currently exists.
>>
>> Would it be possible to use POV-Ray to predict for example signal
>> strength/delay
>> for an indoor scenario? If not, what would be necessary to achieve this?
>
> I suspect that at the frequencies involved, the wavelike nature of the
> electromagnetic radiation becomes too much of an issue to simulate its
> propagation by means of raytracing. If that is the case, then POV-Ray is
> a poor starting point for what you're trying to achieve.
>

In that case, a wave tank simulation could be a better tool.
Another possibility could be some acoustic propagation simulator.

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clipka <ano### [at] anonymousorg> wrote:
> Am 16.01.2014 08:31, schrieb pfefferk:
> > Hello everyone!
> >
> > My field of research makes it necessary to build site-specific propagation
> > models for indoor wireless communication. Unfortunately - to my knowledge - no
> > open source raytracing engine currently exists.
> >
> > Would it be possible to use POV-Ray to predict for example signal strength/delay
> > for an indoor scenario? If not, what would be necessary to achieve this?
>
> I suspect that at the frequencies involved, the wavelike nature of the
> electromagnetic radiation becomes too much of an issue to simulate its
> propagation by means of raytracing. If that is the case, then POV-Ray is
> a poor starting point for what you're trying to achieve.

Yes, the wavelengths and therefore effects differ. What I am interested in is
whether POVray was written to support wave-length-based calculations and is
extensible in that direction.

I guess for a start it would be sufficient to ignore the phase information and
work only with magnitude. As the radiated wave passes through a concrete wall
for example, its power is reduced by 7 dB. The sum of power introduced by all
rays at a certain spot equals the simulated received power.

Does anyone know whether or how this could be achieved?
-- Daniel

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On 20.01.2014 11:41, pfefferk wrote:

> Yes, the wavelengths and therefore effects differ. What I am interested in is
> whether POVray was written to support wave-length-based calculations and is
> extensible in that direction.

Not really. There are a few special places where wavelength is
considered (but mostly fake) to emulate refracted color effects.

> I guess for a start it would be sufficient to ignore the phase information and
> work only with magnitude. As the radiated wave passes through a concrete wall
> for example, its power is reduced by 7 dB. The sum of power introduced by all
> rays at a certain spot equals the simulated received power.

You could set up the transmitter as a light source and the receiver

you either need to model the light source as a bright emissive sphere
or enclose the camera in a double_illuminate'd sphere. Then overall
brightness of (hdr) image should be a kind of "magnitude".

Walls can be partially transparent to allow some light through.
Depending on whether the energy loss occurs at material boundary
or traversing material you can set a transparent pigment or a
fade_distance in the interior.

Diffuse reflection + radiosity could model indirect paths - this
is probably more appropriate than specular reflection + photons?

Of course the approximation may be poor because the light model
used does not reflect your true wave propagation. Also I must say
I never tried double_illuminate with radiosity, not sure this
actually has an effect there.

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Am 20.01.2014 15:52, schrieb Christian Froeschlin:

> I never tried double_illuminate with radiosity, not sure this
> actually has an effect there.

It does work fine. You may need to increase the recursion limit though.

Still, it leaves the problem that ray tracing, even complemented with 
photons and radiosity, can only model linear propagation of 
electromagnetic energy, corresponding to a particle model, leaving /any/ 
effects unaccounted for that arise from the wave-like nature of EM.

Interference is only the most obvious of such effects; a much simpler 
one is the ability of long-wavelength radiation to travel around corners.

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