[Bf-cycles] Rendering with Radio waves
storm
kartochka22 at yandex.ru
Wed Apr 9 17:39:04 CEST 2014
Does not matter interpretation of integrand and sampling dimensions. If
you can describe task as Monte carlo integration problem, Cycles will
fit that perfectly, as most framework already in place. For diffraction
you need another dimension (with addition of wavelength and
polarisation), actual initial phase. And respect that phase in custom
BSDF if material have some weird phase property, and camera sensor
(pixel) intensity depend on phase (mostly based by common path length).
That is all.
В Ср, 09/04/2014 в 16:38 +0300, Antony Riakiotakis пишет:
> It's not refraction that is the serious issue here but diffraction.
>
>
>
> On 9 April 2014 16:20, storm <kartochka22 at yandex.ru> wrote:
> Why not Cycles? It is best integrated with Blender, have very
> well
> tested for years, have two features not related to physical
> property of
> light or anything (think general quasi monte carlo integrator
> framework), optimal triangle/ray intersection test and QMC
> generator.
> And it already work on some GPU as well as most CPU on planet.
>
> 1. Try to get a bit familiar with general build process,
> ckeckout
> blender git tree, compile it, enjoy awesome real time Cycles
> preview
> wingow.
>
> 2. Look at /blender/intern/cycles/kernel/kernel_path.h that
> contain most
> inner integrator loop, function kernel_path_integrate()
> (there are many
> similar named in that file, ignore them for now, they are only
> for very
> special cases)
>
> 3. Look at line "bool hit = scene_intersect(kg, &ray,
> visibility,
> &isect);" it is most time consumer, test arbitraty ray with
> scene and
> return hit related data. Think how to reuse it in your case (i
> think in
> can be used as is w/o any modification)
>
> 4. A bit more complex is main Monte carlo intergator guts
> close to the
> and of loop. Basicaly, qmc generator for dimension used
> "path_state_rng_2D(kg, rng, &state, PRNG_BSDF_U, &bsdf_u,
> &bsdf_v);"
>
> You can stick with path_rng() instead, it return float random
> sample
> between [0,1] for given dimension. You can reuse it for your
> case, to
> sample direction, or polarisation vector, or spectre, only
> need to add
> new dimension in kernel_types.h file.
>
> >From my Point of view, you just need to add few dimensions to
> qmc
> (wavelength, and for polarisation ), and make special BSDF
> node to
> respect them. Few changes, and you get good interactive
> playground for
> your task, with endless possibilities as saving scene,
> converting
> geometry data from many formats, ability to render it as usual
> light for
> debug reason.
>
>
> В Ср, 09/04/2014 в 19:39 +1000, Trevor Anderson пишет:
> > Thanks heaps everyone, I'll have a look into Lux and pbrt.
> > Audio rendering is an interesting idea. Definitely something
> worth
> > considering.
> >
> > I was hoping that at least initially I could limit myself to
> > considering large/smooth enough targets that the optical
> assumptions
> > of light would be sufficient.
> > I plan on taking some test images with a mmW radar system to
> compare
> > to, so I will pay close attention to the interference
> patterns and may
> > need to take another approach, thanks for the input.
> >
> > Cheers,
> > Trev.
> >
> >
> >
> >
> > On Wed, Apr 9, 2014 at 6:56 PM, Ton Roosendaal
> <ton at blender.org>
> > wrote:
> > Hi,
> >
> > For physical accurate wavelength mechanics
> (millimeter waves
> > interference and interaction with matter) you might
> have to
> > build a complete independent system - I'm afraid
> neither
> > cycles or lux would help much here. You probably
> could
> > investigate audio rendering (auralization).
> >
> > Light is in the nanometres spectrum, which allows a
> lot of
> > assumptions and models to simulate an environment
> where light
> > goes around and how to render it. These assumptions
> I wouldn't
> > make for mm waves.
> >
> > -Ton-
> >
> >
> --------------------------------------------------------
> > Ton Roosendaal - ton at blender.org -
> www.blender.org
> > Chairman Blender Foundation - Producer Blender
> Institute
> > Entrepotdok 57A - 1018AD Amsterdam - The
> Netherlands
> >
> >
> >
> > On 9 Apr, 2014, at 8:34, Michael Fox wrote:
> >
> > > I would recommend looking into Luxrender as it has
> full
> > spectral rendering, and is free and opensource and
> have very
> > nice blender intergration, i would ask the luxrender
> people to
> > help you, they are very helpful
> > >
> > > On 09/04/14 16:24, Trevor Anderson wrote:
> > >> Thanks Lukas.
> > >>
> > >> I will take a more serious look at that then. :)
> > >>
> > >> Regards,
> > >> Trev.
> > >>
> > >>
> > >> On Wed, Apr 9, 2014 at 2:41 PM, Lukas Stockner
> > <lukas.stockner at freenet.de> wrote:
> > >> Hi,
> > >> for a project like this, I wouldn't go for Cycles
> since it
> > has no spectral rendering support and a quite
> complicated
> > integrator code.
> > >> My choice would be PBRT, since it has spectral
> support,
> > clean and simple code and great documentation in
> form of a
> > book :)
> > >>
> > >> Lukas Stockner
> > >>
> > >> Am 09.04.2014 01:38 schrieb Trevor Anderson
> > <trevor.g.anderson at gmail.com>:
> > >> >
> > >> > Hi all,
> > >> >
> > >> > I am fairly new to blender and to development
> for that
> > matter. So if anyone can point me in the right
> direction that
> > would be much appreciated. Specifically if there is
> perhaps
> > another open source ray-tracing tool that might be
> better for
> > what I am looking to do.
> > >> >
> > >> > I am looking to use cycles to simulate
> millimetre
> > wavelength radio wave imaging. As part of that I
> suppose I
> > would be looking at trying to track polarization of
> the rays,
> > but primarily changing the wavelengths captured by
> the camera.
> > Ideally also exporting range information too.
> > >> >
> > >> > I was wondering if any of this had been done
> already,
> > even for something like infra-red or hyper-spectral
> imaging,
> > something that would give me a starting point.
> > >> >
> > >> > Thanks,
> > >> > Trev.
> > >> _______________________________________________
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> > >>
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> > >>
> > >>
> > >>
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