I came up with this idea while talking to Mark Wagner on ICQ yesterday. I
was trying to figure out the radiosity settings that Nathan provides, and
discovered I was clueless about brightest_ambient_object. I was using
totally incorrect numbers, and Mark cleared this up for me. What I am
proposing is the following: How about adding some way of making this value
be automatically calculated for adc_bailout? You know, like adding the
keyword "auto" after adc_bailout, or something like that. Could it be done?
Would it help?

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I think this is a good idea (if it can be done).

  The more values that are automatically calculated (but of course modifiable
by hand when needed), the better.
  If the automatically calculated value is bad for a certain scene, you can
fine-tune it by hand, but if the program can automatically calculate a good
value which works for most scenes, that would make it a lot easier to use.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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Can you share what you learned with us?

Mike Wilson

TonyB wrote:

> I came up with this idea while talking to Mark Wagner on ICQ yesterday. I
> was trying to figure out the radiosity settings that Nathan provides, and
> discovered I was clueless about brightest_ambient_object. I was using
> totally incorrect numbers, and Mark cleared this up for me.

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brightest_ambient_object = average of the RGB of the brightest color times
its diffuse. Quoting from Mark Wagner's message to me, this means:

"An object with a color of < 1, 0.5, 0.5 > and a diffuse of 0.8 would have
an average color of 2/3 and a total brightness of 8/15 or 0.53.  An object
with a color of < 2, 2, 2 > and a diffuse of 0.25 would have an average
color of 2 and a total brightness of 0.5.  If your scene consisted of only
those two objects, you would use 0.53 for the brightest_ambient_object."

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Of course, if the light source you use had a brightness of 1.5 instead of
1.0, then you'd want to use 0.53 * 1.5 for that value.

-Nathan

TonyB <ben### [at] panamac-comnet> wrote...
> brightest_ambient_object = average of the RGB of the brightest color times
> its diffuse. Quoting from Mark Wagner's message to me, this means:
>
> "An object with a color of < 1, 0.5, 0.5 > and a diffuse of 0.8 would have
> an average color of 2/3 and a total brightness of 8/15 or 0.53.  An object
> with a color of < 2, 2, 2 > and a diffuse of 0.25 would have an average
> color of 2 and a total brightness of 0.5.  If your scene consisted of only
> those two objects, you would use 0.53 for the brightest_ambient_object."
>
>

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All this is good to know.  I too was wondering about it.

Bob

"Nathan Kopp" <Nat### [at] Koppcom> wrote in message news:392095a0$1@news.povray.org...
{ Of course, if the light source you use had a brightness of 1.5 instead of
{ 1.0, then you'd want to use 0.53 * 1.5 for that value.
{ 
{ -Nathan
{ 
{ TonyB <ben### [at] panamac-comnet> wrote...
{ > brightest_ambient_object = average of the RGB of the brightest color times
{ > its diffuse. Quoting from Mark Wagner's message to me, this means:
{ >
{ > "An object with a color of < 1, 0.5, 0.5 > and a diffuse of 0.8 would have
{ > an average color of 2/3 and a total brightness of 8/15 or 0.53.  An object
{ > with a color of < 2, 2, 2 > and a diffuse of 0.25 would have an average
{ > color of 2 and a total brightness of 0.5.  If your scene consisted of only
{ > those two objects, you would use 0.53 for the brightest_ambient_object."
{ >

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If you have multiple light_sources do you just use the value of the brightest
one in your calculations, or do you need to figure each one's contribution and
find an average or something?

Mike Wilson

Nathan Kopp wrote:

> Of course, if the light source you use had a brightness of 1.5 instead of
> 1.0, then you'd want to use 0.53 * 1.5 for that value.
>
> -Nathan
>
> TonyB <ben### [at] panamac-comnet> wrote...
> > brightest_ambient_object = average of the RGB of the brightest color times
> > its diffuse. Quoting from Mark Wagner's message to me, this means:
> >
> > "An object with a color of < 1, 0.5, 0.5 > and a diffuse of 0.8 would have
> > an average color of 2/3 and a total brightness of 8/15 or 0.53.  An object
> > with a color of < 2, 2, 2 > and a diffuse of 0.25 would have an average
> > color of 2 and a total brightness of 0.5.  If your scene consisted of only
> > those two objects, you would use 0.53 for the brightest_ambient_object."
> >
> >

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Mike Wilson <maw### [at] iastateedu> wrote:
: If you have multiple light_sources do you just use the value of the brightest
: one in your calculations, or do you need to figure each one's contribution and
: find an average or something?

  And of course it will not be the same thing if the light sources are both
illuminating the same side of the object or opposite sides...

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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"Warp" <war### [at] tagpovrayorg> wrote in message news:39214fa4@news.povray.org...
{ Mike Wilson <maw### [at] iastateedu> wrote:
{ : If you have multiple light_sources do you just use the value of the brightest
{ : one in your calculations, or do you need to figure each one's contribution and
{ : find an average or something?
{ 
{   And of course it will not be the same thing if the light sources are both
{ illuminating the same side of the object or opposite sides...
{ 

Sounds a bit more complicated now.

Bob

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To make it easier, simply estimate on the bright side (for adc_bailout).
That might decrease speed, but will help image quality.

-Nathan

Bob Hughes <per### [at] aolcom?subject=PoV-News:> wrote...
> "Warp" <war### [at] tagpovrayorg> wrote in message
news:39214fa4@news.povray.org...
> { Mike Wilson <maw### [at] iastateedu> wrote:
> { : If you have multiple light_sources do you just use the value of the
brightest
> { : one in your calculations, or do you need to figure each one's
contribution and
> { : find an average or something?
>

> {   And of course it will not be the same thing if the light sources are
both
> { illuminating the same side of the object or opposite sides...
>

>
> Sounds a bit more complicated now.
>
> Bob
>
>
>
>

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