>
> Alain<aze### [at] qwertyorg>  wrote:
>> Anyway, I find it dificult to aprehend the reason why, in this case, you
>> may need to use variable ior.
>>
> I'll take a stab in the dark (matter) and guess gravitational lensing.
>
> On a somewhat related note, I'm starting to wonder why scattering media seems to
> be the go-to media for visualizing fields.  I've had good luck applying the much
> less intensive emission media for this purpose to get a good look at some fairly
> gnarly fractal-generating functions.
>
>
>
>
>
Emissive media is visible by itself and is prety fast.
On a minus note, it don't self shadow. The result is that, if it gets 
very thick or have a very high density, it's effect can become to large.

Scattering media behave more like most medias you encounter everywhere. 
It requires some light source to become visible. It self shadow and 
absorbs the light that illuminate it. It's also the slowest kind.

Then, some peoples use a combination of emissive and absorbing media. 
The absorbing media will limit the contribution of the emissive one.

A few application of variable ior:
Gravitational lensing, can be simulated with a properly shaped lense.
Some substance having a non-uniform temperature or salinity. Heated air 
over a flame; fresh water "floating" on sea water; some plastics, mostly 
under stress; fiber optics...

The case of a magnet and it's field don't even come close to those 
cases. Progressive lenses definetly don't use that, they use a complex 
curvature.




Alain

Post a reply to this message

"waggy" <hon### [at] handbasketorg> wrote:
> Alain <aze### [at] qwertyorg> wrote:
> > Anyway, I find it dificult to aprehend the reason why, in this case, you
> > may need to use variable ior.
> >
> I'll take a stab in the dark (matter) and guess gravitational lensing.
>
> On a somewhat related note, I'm starting to wonder why scattering media seems to
> be the go-to media for visualizing fields.  I've had good luck applying the much
> less intensive emission media for this purpose to get a good look at some fairly
> gnarly fractal-generating functions.


Below is how I did the contours of functions that I was mapping.  I found that
if you can map a function to a volume of digital 1-255 values and create a
density file, you can then show the isopotential surfaces of the function in
question.

Matlab has problems doing this, but povray worked perfectly.  I wonder if we
could do the same thing with 3d stereoscopic rendering?

Is there a 3d glasses version of povray?

-----------------------------------------


emission <1,1,1> / 210
      density {
         density_file df3 "tsqrt07j.df3"
         interpolate 1
        color_map {
 [0.01 rgb <0,0,0>]
        [0.03 rgb <0,0,1>]
 [0.05 rgb <0,0,0>]
        [0.07 rgb <0,1,0>]
 [0.09 rgb <0,0,0>]
        [0.11 rgb <1,0,0>]
 [0.13 rgb <0,0,0>]
        [0.15 rgb <0,0,1>]
 [0.17 rgb <0,0,0>]
        [0.19 rgb <0,1,0>]

 [0.21 rgb <0,0,0>]
        [0.23 rgb <1,0,0>]
 [0.25 rgb <0,0,0>]
        [0.27 rgb <0,0,1>]
 [0.29 rgb <0,0,0>]
        [0.31 rgb <0,1,0>]
 [0.33 rgb <0,0,0>]
        [0.35 rgb <1,0,0>]
 [0.37 rgb <0,0,0>]
        [0.39 rgb <0,0,1>]

        [0.41 rgb <0,0,0>]
        [0.43 rgb <0,0,1>]
 [0.45 rgb <0,0,0>]
        [0.47 rgb <0,1,0>]
 [0.49 rgb <0,0,0>]
        [0.51 rgb <1,0,0>]
 [0.53 rgb <0,0,0>]
        [0.55 rgb <0,0,1>]
 [0.57 rgb <0,0,0>]
        [0.59 rgb <0,1,0>]

 [0.61 rgb <0,0,0>]
        [0.63 rgb <1,0,0>]
 [0.65 rgb <0,0,0>]
        [0.67 rgb <0,0,1>]
 [0.69 rgb <0,0,0>]
        [0.71 rgb <0,1,0>]
 [0.73 rgb <0,0,0>]
        [0.75 rgb <1,0,0>]
 [0.77 rgb <0,0,0>]
        [0.79 rgb <0,0,1>]

        [0.81 rgb <0,0,0>]
        [0.83 rgb <0,0,1>]
 [0.85 rgb <0,0,0>]
        [0.87 rgb <0,1,0>]
 [0.89 rgb <0,0,0>]
        [0.91 rgb <1,0,0>]
 [0.93 rgb <0,0,0>]
        [0.95 rgb <0,0,1>]
 [0.97 rgb <0,0,0>]
        [1.00 rgb <1,1,1>]


         }
-----------------------------------------




> Alain <aze### [at] qwertyorg> wrote:
> > Anyway, I find it dificult to aprehend the reason why, in this case, you
> > may need to use variable ior.
> >
> I'll take a stab in the dark (matter) and guess gravitational lensing.
>
Hi Alain,

2d plane IOR is fine, I was exploring the 3d volume data but my real world
expermient is based on a 2d magnetic lens (very thin layer of ferrofluild).
Dark matter and lensing would be easier.

Thank you y'all,

Michael

http://www.aps.org/about/physics-images/heleshaw.cfm

Post a reply to this message

Am 14.05.2011 21:38, schrieb sirzerp:

> Is there a 3d glasses version of povray?

No; but it /can/ be used to produce stereoscopic output, as some guys 
occasionally demonstrate in povray.binaries.images now and again.

Post a reply to this message