I'm having a heck of a time getting media to do what i want it to. I 'm
working on this indoors scene with light pouring through a window (see image
below). I would like to have the appearance of dust particles being
illuminated by the light (a spot light outside the house). Can someone "shed
some light" on what kind of options i need to be using? isotropic scattering
(of yellow, since that is what the spotlight color is. don't know if that is
what i should do though) is what i tried, 10 intervals, 1 -> 5 samples.
There is another light in the scene, a point light that has Reacts with
Media and Attenuated by Media turned off. (i'm using moray to do the scene,
by the way)

the scene either came out all white, or really dark with all the objects
kinda blue, depending on what things I switched around. This is a small
image of the scene layout to help show what i am trying to do, where light
is comming from, whatever. I've never succesfully used media before, i could
sure use some help.

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Ross Litscher wrote:
> 
> I'm having a heck of a time getting media to do what i want it to. I 'm
> working on this indoors scene with light pouring through a window (see image
> below). I would like to have the appearance of dust particles being
> illuminated by the light (a spot light outside the house). Can someone "shed
> some light" on what kind of options i need to be using? isotropic scattering
> (of yellow, since that is what the spotlight color is. don't know if that is
> what i should do though) is what i tried, 10 intervals, 1 -> 5 samples.
> There is another light in the scene, a point light that has Reacts with
> Media and Attenuated by Media turned off. (i'm using moray to do the scene,
> by the way)
> 
> the scene either came out all white, or really dark with all the objects
> kinda blue, depending on what things I switched around. This is a small
> image of the scene layout to help show what i am trying to do, where light
> is comming from, whatever. I've never succesfully used media before, i could
> sure use some help.
> 
>  [Image]

 I really cnat tell much from your image but I cna offer some help I
believe. On 04-09-1999 I posted two images that accomplished what
you are attempting. The second post that day titled "Patend Issued"
has the source code for the scene attached to the end of the message.
It should give you some insperation and paramters to try. Usualy you
will find the mistake is from not using a bright enough light source
for the media intereaction. Try values for the light source on the
order of light_source { <0,0,0> rgb 1.5 } . 1.5 can even be on the
low side and I have gone as high as 10 before.

  Also Mike Hough has two good tutorials on his site about this type
of media an has been the basis of my own success in this regard.

http://members.xoom.com/POVRAY3/media1.html
http://members.xoom.com/POVRAY3/media2.html

-- 
Ken Tyler

mailto://tylereng@pacbell.net

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I've had some success... (See Media and Atmosphere posts from a few
weeks back) but it is kinda a case by case thing.  If you'd let me play
with some of your source, I might be able to send you on the right
track.  For now, think very low scattering value (0.15 or so) and low
extinction 0.1 or so... also, kick the samples up for the final... 15-50
or some such.


Steve


Ross Litscher wrote:
> 
> I'm having a heck of a time getting media to do what i want it to. I 'm
> working on this indoors scene with light pouring through a window (see image
> below). I would like to have the appearance of dust particles being
> illuminated by the light (a spot light outside the house). Can someone "shed
> some light" on what kind of options i need to be using? isotropic scattering
> (of yellow, since that is what the spotlight color is. don't know if that is
> what i should do though) is what i tried, 10 intervals, 1 -> 5 samples.
> There is another light in the scene, a point light that has Reacts with
> Media and Attenuated by Media turned off. (i'm using moray to do the scene,
> by the way)
> 
> the scene either came out all white, or really dark with all the objects
> kinda blue, depending on what things I switched around. This is a small
> image of the scene layout to help show what i am trying to do, where light
> is comming from, whatever. I've never succesfully used media before, i could
> sure use some help.
> 
>  [Image]

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Stephen Lavedas wrote in message <3734F160.367B08D0@virginia.edu>...
>I've had some success... (See Media and Atmosphere posts from a few
>weeks back) but it is kinda a case by case thing.  If you'd let me play
>with some of your source, I might be able to send you on the right
>track.  For now, think very low scattering value (0.15 or so) and low
>extinction 0.1 or so... also, kick the samples up for the final... 15-50
>or some such.
>
>
>Steve
>
>

hey, great I'll start with this, and cranking up the light source a little
bit more. thanks

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It's a neat picture, even if sparsely populated with objects. I don't
understand what those two tiny objects are at all. But it looks like a oil
painting to me, pretty neat. Hope any media success doesn't change that
aspect too much. Your trouble sounds just like the things about
'atmosphere' from version 3.0*. Either too thin or too thick. You could
try lowering density floats or vectors as you raise the scattering
(emission and/or absorption also) float or vector and vice versa.
Basically you have to give the light enough to interact with while not
inundating the media too much.
As Stephen pointed out it will always depend on the scene, like area
confines and lighting.


Ross Litscher wrote:
> 
> I'm having a heck of a time getting media to do what i want it to. I 'm
> working on this indoors scene with light pouring through a window (see image
> below). I would like to have the appearance of dust particles being
> illuminated by the light (a spot light outside the house). Can someone "shed
> some light" on what kind of options i need to be using? isotropic scattering
> (of yellow, since that is what the spotlight color is. don't know if that is
> what i should do though) is what i tried, 10 intervals, 1 -> 5 samples.
> There is another light in the scene, a point light that has Reacts with
> Media and Attenuated by Media turned off. (i'm using moray to do the scene,
> by the way)
> 
> the scene either came out all white, or really dark with all the objects
> kinda blue, depending on what things I switched around. This is a small
> image of the scene layout to help show what i am trying to do, where light
> is comming from, whatever. I've never succesfully used media before, i could
> sure use some help.
> 
>  [Image]

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/homepage.htm
 mailto://inversez@aol.com?Subject=PoV-News

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Bob Hughes wrote in message <3735C28C.D54EBFF7@aol.com>...
>It's a neat picture, even if sparsely populated with objects. I don't
>understand what those two tiny objects are at all. But it looks like a oil
>painting to me, pretty neat. Hope any media success doesn't change that
>aspect too much. Your trouble sounds just like the things about
>'atmosphere' from version 3.0*. Either too thin or too thick. You could
>try lowering density floats or vectors as you raise the scattering
>(emission and/or absorption also) float or vector and vice versa.
>Basically you have to give the light enough to interact with while not
>inundating the media too much.
>As Stephen pointed out it will always depend on the scene, like area
>confines and lighting.
>
>
>

those little things are cork stoppers for test tubes that aren't in the
scene. right now cause they took a while to render among other reasons. I'll
definately post the completed image in a few days. I think it is looking
pretty cool so far. thanks for the advice. i never got down the atmopshpere
stuff in 3.0 either. maybe i'll just leave it out of the scene.

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Well, I didn't say they looked like cork stoppers before did I but I
thought they were. I just wasn't going to make a fool of myself,
seriously. The mid-air thing through me off.


Ross Litscher wrote:
> 
> Bob Hughes wrote in message <3735C28C.D54EBFF7@aol.com>...
> >It's a neat picture, even if sparsely populated with objects. I don't
> >understand what those two tiny objects are at all. But it looks like a oil
> >painting to me, pretty neat. Hope any media success doesn't change that
> >aspect too much. Your trouble sounds just like the things about
> >'atmosphere' from version 3.0*. Either too thin or too thick. You could
> >try lowering density floats or vectors as you raise the scattering
> >(emission and/or absorption also) float or vector and vice versa.
> >Basically you have to give the light enough to interact with while not
> >inundating the media too much.
> >As Stephen pointed out it will always depend on the scene, like area
> >confines and lighting.
> >
> >
> >
> 
> those little things are cork stoppers for test tubes that aren't in the
> scene. right now cause they took a while to render among other reasons. I'll
> definately post the completed image in a few days. I think it is looking
> pretty cool so far. thanks for the advice. i never got down the atmopshpere
> stuff in 3.0 either. maybe i'll just leave it out of the scene.

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/homepage.htm
 mailto://inversez@aol.com?Subject=PoV-News

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