Hello All,

  Me again of course..

  I'm doign some testing with Media interaction.. so I made a line of
Spotlights, using a while statment.
  Inside the light_source  I have media_attenuation turned on
  Outside the block, I have atmospheric media create (I think).
    media {
        method 3
        scattering { 1, color rgb .02 }
    }

    When I render the scene, the only change I see is that it renders
slower.. I don't see what I expected, which would be a cone of light from
the spotlight..

Anyone got any suggestions??

Thanks
Dave

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I've run into that one some weeks ago.

Its about the intervals and samples and such. In an
infinite section, how do you calculate intervals?

This is somehow the reason why only spotlight don't
work, try a fading light... The algorithm of method 3 is,
as far as I know, an adaptive one. But it can only adapt
to things "it" sees. If it cannot spot them (intervals in infinity...),
it cannot adapt properly.

And thus POV probably thinks that the spotlights don't
add too much...

But that's just my interpretation of things, and I'm, no expert
on that. Someone just told me that infinite-space and method 3
don't work very well together on certain occasions.

Dave Bates wrote:

> Hello All,
>
>   Me again of course..
>
>   I'm doign some testing with Media interaction.. so I made a line of
> Spotlights, using a while statment.
>   Inside the light_source  I have media_attenuation turned on
>   Outside the block, I have atmospheric media create (I think).
>     media {
>         method 3
>         scattering { 1, color rgb .02 }
>     }
>
>     When I render the scene, the only change I see is that it renders
> slower.. I don't see what I expected, which would be a cone of light from
> the spotlight..
>
> Anyone got any suggestions??
>
> Thanks
> Dave

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

Post a reply to this message

Think I should try a different method?

I heard 3 was the best, but I Can try 1 .. See what that does..

:)
"Tim Nikias" <tim### [at] gmxde> wrote in message
news:3CE5A23B.85DE1A32@gmx.de...
> I've run into that one some weeks ago.
>
> Its about the intervals and samples and such. In an
> infinite section, how do you calculate intervals?
>
> This is somehow the reason why only spotlight don't
> work, try a fading light... The algorithm of method 3 is,
> as far as I know, an adaptive one. But it can only adapt
> to things "it" sees. If it cannot spot them (intervals in infinity...),
> it cannot adapt properly.
>
> And thus POV probably thinks that the spotlights don't
> add too much...
>
> But that's just my interpretation of things, and I'm, no expert
> on that. Someone just told me that infinite-space and method 3
> don't work very well together on certain occasions.
>

Post a reply to this message

Well no.. I tried to take out the samles and interaction, with and without,
method 1-3 everything seems the same.. these spots are Projecting on a Box..
It's long, but it's not infinate.. .. Any more suggestions Tim..
"Tim Nikias" <tim### [at] gmxde> wrote in message
news:3CE5A23B.85DE1A32@gmx.de...
> I've run into that one some weeks ago.
>
> Its about the intervals and samples and such. In an
> infinite section, how do you calculate intervals?
>
> This is somehow the reason why only spotlight don't
> work, try a fading light... The algorithm of method 3 is,
> as far as I know, an adaptive one. But it can only adapt
> to things "it" sees. If it cannot spot them (intervals in infinity...),
> it cannot adapt properly.
>
> And thus POV probably thinks that the spotlights don't
> add too much...
>
> But that's just my interpretation of things, and I'm, no expert
> on that. Someone just told me that infinite-space and method 3
> don't work very well together on certain occasions.
>
> Dave Bates wrote:
>
> > Hello All,
> >
> >   Me again of course..
> >
> >   I'm doign some testing with Media interaction.. so I made a line of
> > Spotlights, using a while statment.
> >   Inside the light_source  I have media_attenuation turned on
> >   Outside the block, I have atmospheric media create (I think).
> >     media {
> >         method 3
> >         scattering { 1, color rgb .02 }
> >     }
> >
> >     When I render the scene, the only change I see is that it renders
> > slower.. I don't see what I expected, which would be a cone of light
from
> > the spotlight..
> >
> > Anyone got any suggestions??
> >
> > Thanks
> > Dave
>
> --
> Tim Nikias
> Homepage: http://www.digitaltwilight.de/no_lights/index.html
> Email: Tim### [at] gmxde
>
>

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I suggest you post the relevant parts of your source code: camera, light(s),
and all the media (and their container objects) that are having problems.

 - Slime
[ http://www.slimeland.com/ ]

Post a reply to this message

Sure here you:

media {
//    method 3
    scattering { 1, color rgb .02 }
//    intervals 1
    samples 5
    method 1
}

camera {
    location <-4, 3, -5>
    look_at .5
}

And here are the lights:
#declare spot_space=3.1;
#declare max_run=125;

#declare l_rad = 8;
#declare l_x = .25;
#declare l_z = -6;

#while (l_z < max_run)
    light_source {
        <l_x, 5, l_z>
        rgb <1,1,1>
        spotlight
        point_at <l_x, 0, l_z>
        radius l_rad
        falloff l_rad*2
        tightness 25
        media_attenuation on
    }
    #declare l_z = l_z + spot_space;
#end


This is projected to a BOX..
The spots all work fine, just the MEdia I'm having problems with.
"Slime" <slm### [at] slimelandcom> wrote in message
news:3ce5b3bb$1@news.povray.org...
> I suggest you post the relevant parts of your source code: camera,
light(s),
> and all the media (and their container objects) that are having problems.
>
>  - Slime
> [ http://www.slimeland.com/ ]
>
>

Post a reply to this message

Hi Norman--- er, Dave.

I don't see anything wrong here, using 3.5.beta.RC4.

Media method 3 is smooth with just your original scene script. Only thing
is, I needed to multiply your camera location by 3 in order to see a light
"cone" because of how close it is.

bob h

Post a reply to this message

I traced your scene and played a little with it.

One thing I noticed is that you have to take
into account that scattering media also darkens
the image as too much dust may "eat" the light.

Another one: Looks at beta-test, there's
a post on the 6. May from with title
"Media broken?", in which I ran into
that same problem.

I am not really sure, what the nature of this
effect is. Its all about sampling, intervals,
scatterings affection on the colors ect, so
it might just be look if you hit the correct
combination.

Peter Popov told me there to look at "ratio",
which places more samples in lit areas than
in unlit ones. Altogether I think this subject
could be made more clear by someone
who actually wrote the code and has some
specific insight. I didn't fully understand
why spotlights are not infinite and may be
traced in infinite media better than pointlights
in infinite media etc.



"Dave Bates [{Norman}]" wrote:

> Sure here you:
>
> media {
> //    method 3
>     scattering { 1, color rgb .02 }
> //    intervals 1
>     samples 5
>     method 1
> }
>
> camera {
>     location <-4, 3, -5>
>     look_at .5
> }
>
> And here are the lights:
> #declare spot_space=3.1;
> #declare max_run=125;
>
> #declare l_rad = 8;
> #declare l_x = .25;
> #declare l_z = -6;
>
> #while (l_z < max_run)
>     light_source {
>         <l_x, 5, l_z>
>         rgb <1,1,1>
>         spotlight
>         point_at <l_x, 0, l_z>
>         radius l_rad
>         falloff l_rad*2
>         tightness 25
>         media_attenuation on
>     }
>     #declare l_z = l_z + spot_space;
> #end
>
> This is projected to a BOX..
> The spots all work fine, just the MEdia I'm having problems with.
> "Slime" <slm### [at] slimelandcom> wrote in message
> news:3ce5b3bb$1@news.povray.org...
> > I suggest you post the relevant parts of your source code: camera,
> light(s),
> > and all the media (and their container objects) that are having problems.
> >
> >  - Slime
> > [ http://www.slimeland.com/ ]
> >
> >

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

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Bob,

    Okay here is my question.. I've played aroudn with this a bit.. I added
a "Container" box and see the Cone faintly.. but Is there a way to make it
more intense without raising the intesity of the light?


"bob h" <omn### [at] charternet> wrote in message
news:3ce5f0f8$1@news.povray.org...
> Hi Norman--- er, Dave.
>
> I don't see anything wrong here, using 3.5.beta.RC4.
>
> Media method 3 is smooth with just your original scene script. Only thing
> is, I needed to multiply your camera location by 3 in order to see a light
> "cone" because of how close it is.
>
> bob h
>
>
>

Post a reply to this message

>     Okay here is my question.. I've played aroudn with this a bit.. I
added
> a "Container" box and see the Cone faintly.. but Is there a way to make it
> more intense without raising the intesity of the light?

Scattering media is hard to manipulate well. You should either increase or
decrease the color of the scattering (which is currently .02 i believe).
Increasing it may help because there will be more media for the light to
reflect off of, so it will be brighter. But decreasing may help because
there will be less unlit media blocking the light that *is* reflecting.

If you are only interested in seeing the media where the fog is, you may
want to ditch the scattering media and replace it with emission media in a
cone shape that matches the spotlight.

 - Slime
[ http://www.slimeland.com/ ]

Post a reply to this message