I've been using Pov for awhile now, but I've always been a bit confused
about the "ambient" and "diffuse" keywords in the finish block of an
object.  My understanding is as follows:

When a light source in the scene is shining on an object, that object's
"diffuse" value determines how much of that light is reflected to the
camera (is it a percentage, 0-1 being 0-100% ?).

An object's "ambient" value determines the amount of ambient light (i.e,
light striking the surface of an object from all directions and from no
particular light sourfce) (is this also a percentage?) reflected off the
object to the camera.

Is this correct?  The documentation seems to state that "diffuse"
determines the percentage of the light you see reflecting off an object
that is actually light from light sources being reflected diffusely.  If
this were the case, "diffuse 1" would cause the object to reflect no
ambient light, which is of coarse not the case.  Any help would be
greatly apprectiated... I'm confused;-)  Thanks in advance.

Jordan

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Diffuse is the percentage of light from light_sources reflected 
"diffusely" from the surface, ambient is the same thing, except for the 
ambient "light source" defined by ambient_light in global_settings. The 
default ambient light is white, so you can use "ambient 1 diffuse 0" to 
specify all points on your are illuminated with a white ambient light 
(that is, a light with no position or direction, that fills space)
Or you could use "ambient 0 diffuse 1" to specify that the only 
illumination comes from light_sources. In that case, completely shadowed 
areas will be pure black.

Basically, ambient specifies a "minimum illumination", and diffuse 
specifies the effect of light_sources. I generally try to make sure 
ambient+diffuse+reflection <= 1 to get more realistic 
textures...otherwise, your surface is reflecting more light than it 
absorbs. Also, giving everything an ambient of 0 and using radiosity 
gives very realistic shading...

And though these are percentages (with 1 being 100%), you can go outside 
the [0, 1] range...while this is usually not realistic, it is useful in 
radiosity, where you can make an object glow by giving it a very high 
ambient value.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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Well, thanks for clearing that up!  Now, if only they explained it that
way in the documentation;-)  Maybe it's just a weird interpretation on
my part.  Anyways, thanks again.

Jordan

<><

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They are both percentages, but the language is maybe a tad ambiguous.

Diffuse = percent of light hitting being reflected. And despite popular
belief, percentages are not constrained to [0,1], but you already knew that.
:)

Ambient = percent of ambient light level being reflected, sort of, I guess.
There is a parameter ambient_light you can specify in global_settings, and
no surprise, changing this scales all of your objects' ambience.

It seemed kind of strange to me at first; I thought the "ambient_light"
would factor into an object's diffuse because it still comes from outside
the object, whereas "ambient" would mean light given off by the object
itself. That way you also wouldn't have to keep changing the ambience of
"glowing" objects when changing the general ambient lighting level. Once you
figure it out though it's an easy system to adapt, and it might as well be
kept for continuity's sake. There's always little debates here over the
mechanics of this and that.

--
David Fontaine  <dav### [at] faricynet>  ICQ 55354965
My raytracing gallery:  http://davidf.faricy.net/

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"Hookflash" <hoo### [at] hotmailcom> wrote in message
news:3A5### [at] hotmailcom...

I was wondering about this the other day.

I think that, in particular, diffuse and reflection are highly dependant on
each other in REAL LIFE (tm). To be able to specify them separately is
unrealistic but useful - it's as though you had a program to simulate the
action of electricy that allowed you to specify voltage, current and
resistance independantly of each other.

My intuition is that diffuse and reflection should add to 1. Light falling
on an object that isn't reflected is diffused and visa versa. Ambient, on
the other hand, is a "fake" effect to simulate radiosity in a scene.

Post a reply to this message

Tom Melly <tom### [at] tomandlucouk> wrote in message
news:3a5d7f8a$1@news.povray.org...
> "Hookflash" <hoo### [at] hotmailcom> wrote in message
> news:3A5### [at] hotmailcom...
>
> My intuition is that diffuse and reflection should add to 1.

Asuming the object does not absorb light. I recall reading in some
tutoial or book that diffuse should not be set to 1 as no object diffusely
reflects
all light falling on it.

I tend to work by the rule that ambient + diffuse + reflection < 1 unless
I'm trying
for some odd effect

Gail
********************************************************************
* gsh### [at] monotixcoza              * System.dat not found.         *
* http://www.rucus.ru.ac.za/~gail/ * Reformat hard drive Y)es O)k  *
********************************************************************
* If at first you don't succeed, call it version 1.0               *
********************************************************************

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"Gail Shaw" <gsh### [at] monotixcoza> wrote in message
news:3a5d8947@news.povray.org...
>
>
> Asuming the object does not absorb light. I recall reading in some
> tutoial or book that diffuse should not be set to 1 as no object diffusely
> reflects
> all light falling on it.
>
> I tend to work by the rule that ambient + diffuse + reflection < 1 unless
> I'm trying
> for some odd effect
>
> Gail

I wondered about that, and consequently left it out. Aren't absorption and
pigment the same? i.e. the colour of an object is the colour of the light
that isn't absorped? Also, IMHO, ambient should be in a separate calc. Dunno
what though.

Post a reply to this message

In article <3a5d8947@news.povray.org>, "Gail Shaw" 
<gsh### [at] monotixcoza> wrote:

> Asuming the object does not absorb light. I recall reading in some 
> tutoial or book that diffuse should not be set to 1 as no object 
> diffusely reflects all light falling on it.

Also, if you are using a pigment that is darker than pure white, that 
will give a lower diffuse. The diffuse keyword just allows you to adjust 
the whole thing...

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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On Thu, 11 Jan 2001 09:40:26 -0000, Tom Melly wrote:
>My intuition is that diffuse and reflection should add to 1. Light falling
>on an object that isn't reflected is diffused and visa versa. Ambient, on
>the other hand, is a "fake" effect to simulate radiosity in a scene.

Don't forget filter/transmit and specular.  Those should be included in your
sum as well.

Ambient is equivalent to "diffuse reflection from unknown light sources" and
as such should probably also be included in the sum.  I always include it in
the sum, at any rate.

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.

Post a reply to this message

"Ron Parker" <ron### [at] povrayorg> wrote in message
news:slr### [at] fwicom...
>
> Ambient is equivalent to "diffuse reflection from unknown light sources"
and
> as such should probably also be included in the sum.  I always include it
in
> the sum, at any rate.
>

Yes, it should be included - I'm just not sure how. After all, for an object
in deep space, ambient would be pretty much 0 for all objects. Which seems
to imply that ambient is a property of the scene rather than the object.
However, an object with reflection 1 always has, by implication, an ambient
of 0, which implies that it is an attribute of the object.

The trouble with ambient is that to make any real sense it should be
influenced by the overall strength of the light-sources available. Perhaps
one should code like this:

#declare light_strength = 0.75;
light_source{<0,0,0> color rgb<1,1,1>*light_strength translate <-300,
300, -300>}
object{foo finish{ambient 0.3*light_strength}}

Post a reply to this message

On Thu, 11 Jan 2001 13:45:07 -0000, Tom Melly wrote:
>The trouble with ambient is that to make any real sense it should be
>influenced by the overall strength of the light-sources available. Perhaps
>one should code like this:
>
>#declare light_strength = 0.75;
>light_source{<0,0,0> color rgb<1,1,1>*light_strength translate <-300,
>300, -300>}
>object{foo finish{ambient 0.3*light_strength}}

But one does code like that, if one knows about the all-important
global_settings { ambient_light COLOR } setting.  Just look at it
as a big shadowless light source that casts light in all directions 
from everywhere.

So, the ambient setting in a finish statement seems to me as though it
should be closely related to diffuse, particularly if brilliance is low.
As brilliance goes up, ambient should go down relative to diffuse.  As
diffuse goes up, ambient should also go up.

If I were to propose a rule of thumb, I would say ambient and diffuse
should be roughly the same number, and that ambient shouldn't be included
in the requirement that filter+transmit+reflection+diffuse+specular <= 1.

The logic behind the first part is that ambient is just diffuse reflection
of light with an unspecified source, so if an object diffusely reflects
60% of any light falling on it, it should diffusely reflect 60% of the
ambient light.  (If this makes your scene too bright, turn down the ambient
light in global_settings or consider using radiosity instead of ambient
light.)

The logic behind the second part is that what an object does with light 
from unspecified sources shouldn't have any effect on what it does with 
light from a specific source.  That is, you wouldn't keep everything
below .5 just because you have two light sources, so there's no reason
to do so because you have ambient light.

Actually, now that I think about it, I'm not so sure both specular and 
reflection should be in the sum either, since the purpose of specular is 
to simulate reflection for light sources.  By the same logic, specular and
reflection should probably be fairly closely related unless you're using
blurred reflection in MegaPOV.

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.

Post a reply to this message

"Ron Parker" <ron### [at] povrayorg> wrote in message
news:slr### [at] fwicom...
>
> But one does code like that, if one knows about the all-important
> global_settings { ambient_light COLOR } setting.  Just look at it
> as a big shadowless light source that casts light in all directions
> from everywhere.
>

Well, yes, but even using global ambient, the ambient of objects won't
change as you adjust the strength of the light-sources in the image.

> So, the ambient setting in a finish statement seems to me as though it
> should be closely related to diffuse, particularly if brilliance is low.

Yes.

> As brilliance goes up, ambient should go down relative to diffuse.  As
> diffuse goes up, ambient should also go up.
>
> If I were to propose a rule of thumb, I would say ambient and diffuse
> should be roughly the same number, and that ambient shouldn't be included
> in the requirement that filter+transmit+reflection+diffuse+specular <= 1.
>

I'm sure you're right - however, understanding this would require me to
think of more than two things at the same time, so I cannot verify ;)

Post a reply to this message

Ron Parker wrote:
> 
> If I were to propose a rule of thumb, I would say ambient and diffuse
> should be roughly the same number, and that ambient shouldn't be included
> in the requirement that filter+transmit+reflection+diffuse+specular <= 1.

Even though, you hint on it in the next paragraph, you should point out
that this formula is only valid if you are not using radiosity.

> 
> The logic behind the first part is that ambient is just diffuse reflection
> of light with an unspecified source, so if an object diffusely reflects
> 60% of any light falling on it, it should diffusely reflect 60% of the
> ambient light.  (If this makes your scene too bright, turn down the ambient
> light in global_settings or consider using radiosity instead of ambient
> light.)
> 
> The logic behind the second part is that what an object does with light
> from unspecified sources shouldn't have any effect on what it does with
> light from a specific source.  That is, you wouldn't keep everything
> below .5 just because you have two light sources, so there's no reason
> to do so because you have ambient light.
> 
> Actually, now that I think about it, I'm not so sure both specular and
> reflection should be in the sum either, since the purpose of specular is
> to simulate reflection for light sources.  By the same logic, specular and
> reflection should probably be fairly closely related unless you're using
> blurred reflection in MegaPOV.
> 
> --
> Ron Parker   http://www2.fwi.com/~parkerr/traces.html
> My opinions.  Mine.  Not anyone else's.

-- 
Francois Labreque | Unfortunately, there's no such thing as a snooze
    flabreque     | button on a cat who wants breakfast.
        @         |      - Unattributed quote from rec.humor.funny
   videotron.ca

Post a reply to this message

Tom Melly wrote:
> 
> "Ron Parker" <ron### [at] povrayorg> wrote in message
> news:slr### [at] fwicom...
> >
> > But one does code like that, if one knows about the all-important
> > global_settings { ambient_light COLOR } setting.  Just look at it
> > as a big shadowless light source that casts light in all directions
> > from everywhere.
> >
> 
> Well, yes, but even using global ambient, the ambient of objects won't
> change as you adjust the strength of the light-sources in the image.

If global ambient is linked to the strength of your light sources (or
number thereof) via something similar to the "ambient
0.3*Light_Strength*light_num", then the induvidual ambient of objects
doesn't need to be played with as long as you also take into account the
proximity of the light sources to the object (as someone mentioned
earlier: in space, there is very little ambient) when giving these
objects ambient values in the first place.

I personally prefer setting ambient to 0 and let radiosity take care of
all this stuff.  But then again, I have the horsepower necessary for it,
so ymmv.

-- 
Francois Labreque | Unfortunately, there's no such thing as a snooze
    flabreque     | button on a cat who wants breakfast.
        @         |      - Unattributed quote from rec.humor.funny
   videotron.ca

Post a reply to this message

"Francois Labreque" <fla### [at] videotronca> wrote in message
news:3A5DCD94.E1942106@videotron.ca...
>
> If global ambient is linked to the strength of your light sources (or
> number thereof) via something similar to the "ambient
> 0.3*Light_Strength*light_num", then the induvidual ambient of objects

Pretty much what I suggested earlier.

>
> I personally prefer setting ambient to 0 and let radiosity take care of
> all this stuff.  But then again, I have the horsepower necessary for it,
> so ymmv.
>

I personally prefer it if people don't rub my nose in the fact that a P90 is
not the ideal rendering platform - particularily if they're french ;)

Post a reply to this message

On Thu, 11 Jan 2001 14:54:52 -0000, Tom Melly wrote:
>Well, yes, but even using global ambient, the ambient of objects won't
>change as you adjust the strength of the light-sources in the image.

Well, I'm of the opinion that if the amount of ambient light you have in
your scene is that dependent on individual light sources, you should be
using radiosity.

But then, I'm also of the opinion that we shouldn't have to adjust the 
brightness of light sources.  Am I alone in wishing there were an "exposure"
option in the camera specification?

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.

Post a reply to this message

On Thu, 11 Jan 2001 10:06:23 -0500, Francois Labreque wrote:
>
>
>Ron Parker wrote:
>> 
>> If I were to propose a rule of thumb, I would say ambient and diffuse
>> should be roughly the same number, and that ambient shouldn't be included
>> in the requirement that filter+transmit+reflection+diffuse+specular <= 1.
>
>Even though, you hint on it in the next paragraph, you should point out
>that this formula is only valid if you are not using radiosity.

From a purely theoretical standpoint, I fail to see why this should be
the case for objects that don't emit their own light (other than the 
reflection/specular thing.)  Could you elaborate?

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.

Post a reply to this message

On 11 Jan 2001 10:56:04 -0500, Ron Parker wrote:
>On Thu, 11 Jan 2001 14:54:52 -0000, Tom Melly wrote:
>>Well, yes, but even using global ambient, the ambient of objects won't
>>change as you adjust the strength of the light-sources in the image.
>
>Well, I'm of the opinion that if the amount of ambient light you have in
>your scene is that dependent on individual light sources, you should be
>using radiosity.

And believe it or not, I'm still of that opinion despite the fact that
this machine is only a P200.  But then, I don't render much these days.

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.

Post a reply to this message

"Ron Parker" <ron### [at] povrayorg> wrote in message
news:slr### [at] fwicom...
> On 11 Jan 2001 10:56:04 -0500, Ron Parker wrote:
>
>But then, I don't render much these days.

On a P200 with radiosity, no one renders much these days....

Post a reply to this message

On Thu, 11 Jan 2001 16:13:36 -0000, Tom Melly wrote:
>
>"Ron Parker" <ron### [at] povrayorg> wrote in message
>news:slr### [at] fwicom...
>> On 11 Jan 2001 10:56:04 -0500, Ron Parker wrote:
>>
>>But then, I don't render much these days.
>
>On a P200 with radiosity, no one renders much these days....

Well, sometimes I cheat and use Julie's K6-2/400.  But it runs Windows, so
it doesn't perform much better.  (Just kidding, guys!  Please cut me down
now!)

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.

Post a reply to this message

Just a thought:
If dust from this discussion is settled down and common ground is found,
then perhaps someone could summarize it and put it available (e.g. as
guideline for rule-of-thumb)?

Post a reply to this message

Vahur Krouverk wrote:
> 
> Just a thought:
> If dust from this discussion is settled down and common ground is found,
> then perhaps someone could summarize it and put it available (e.g. as
> guideline for rule-of-thumb)?

You will probably find that on this topic that one mans rule of thumb
is another mans big toe.

-- 
Ken Tyler - 1400+ POV-Ray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

Post a reply to this message

On Thu, 11 Jan 2001 08:45:50 -0800, Ken wrote:
>
>
>Vahur Krouverk wrote:
>> 
>> Just a thought:
>> If dust from this discussion is settled down and common ground is found,
>> then perhaps someone could summarize it and put it available (e.g. as
>> guideline for rule-of-thumb)?
>
>You will probably find that on this topic that one mans rule of thumb
>is another mans big toe.

What he said.

The only general rule of thumb is "tweak it til it looks right in your scene."

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.

Post a reply to this message

"Vahur Krouverk" <vah### [at] aetecee> wrote in message
news:3A5DE21E.13B70413@aetec.ee...
> Just a thought:
> If dust from this discussion is settled down and common ground is found,
> then perhaps someone could summarize it and put it available (e.g. as
> guideline for rule-of-thumb)?

1. A scene with white walls needs higher ambient than a scene with black
walls.

2. Ambient and diffuse have a relationship to each other and an inverse
relationship to reflection.

3. Don't use ambient, use radiosity. With media. And isosurfaces. On a 386.

Post a reply to this message

Tom Melly wrote:
> 1. A scene with white walls needs higher ambient than a scene with black
> walls.
> 
> 2. Ambient and diffuse have a relationship to each other and an inverse
> relationship to reflection.
> 
> 3. Don't use ambient, use radiosity. With media. And isosurfaces. On a 386.
Guess I should downgrade my 486 in this case...

Arghh, I'm off to read "Digital Lighting & Rendering"

Post a reply to this message

In article <3A5DE21E.13B70413@aetec.ee>, Vahur Krouverk 
<vah### [at] aetecee> wrote:

> Just a thought:
> If dust from this discussion is settled down and common ground is found,
> then perhaps someone could summarize it and put it available (e.g. as
> guideline for rule-of-thumb)?

As mentioned, pretty much everyone has their own "rule of thumb", and 
you will have to just develop your own. However, this is how I do 
things, but note that much of this applies to MegaPOV only:

Make sure ambient+diffuse+reflection <= 1
(I don't include specular in this, because it only applies to certain 
angles relative to each light_source...just adjust it until you get the 
highlights you want. I never use phong highlights. If you use 
iridescence, that should probably go into the above calculations.)

metallic on
reflect_metallic on
conserve_energy on
Use Fresnel reflection function if applicable (a surprisingly large 
number of situations).

I get best results with ambient 0 and radiosity. A high ambient robs the 
scene of contrast and depth, so the only times I use an ambient other 
than 0 is when I have a glowing object or have an object that just needs 
to show up (I sometimes use ambient 1 cylinders aligned along each axis 
for orientation). For test renders, I usually don't use radiosity, but I 
put a light_source at the position of the camera. This helps illuminate 
dark shadows but doesn't destroy the depth cues like ambient does.

Also, I always use "filter", never "transmit" for transparence. When I'm 
going for a realistic transparent material, I use a filter value of 1 
and use absorbing media or fade_color (using the "realistic attenuation" 
function) to tint the glass to the right color. This makes thick areas 
dark and very thin areas almost invisible, which is how things work in 
reality.
Dispersion can add a very nice touch, and photons can really add to your 
scene if you have reflective/refracting objects and something they can 
cast light on (mainly dull surfaces or media, anything you would notice 
light caustics on normally).

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

Post a reply to this message

On Thu, 11 Jan 2001 16:42:22 -0500, Chris Huff wrote:
>Also, I always use "filter", never "transmit" for transparence. When I'm 
>going for a realistic transparent material, I use a filter value of 1 
>and use absorbing media or fade_color (using the "realistic attenuation" 
>function) to tint the glass to the right color. This makes thick areas 
>dark and very thin areas almost invisible, which is how things work in 
>reality.

Transmit has a different purpose.  Transmit is supposed to be used for
things like gauze or nylon fabric or tracing paper or other things that 
are transparent because they have a bunch of tiny subpixel holes in them 
rather than because they are made of a semitransparent material.

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.

Post a reply to this message

In article <slr### [at] fwicom>, ron### [at] povrayorg 
wrote:

> Transmit has a different purpose.  Transmit is supposed to be used for
> things like gauze or nylon fabric or tracing paper or other things that 
> are transparent because they have a bunch of tiny subpixel holes in them 
> rather than because they are made of a semitransparent material.

True...there are exceptions to that rule. None of them are completely 
rigid...but that would be a good addition to that rule, and I will keep 
it in mind from now on.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

Post a reply to this message

Ron Parker wrote:

> Ambient is equivalent to "diffuse reflection from unknown light sources" and
> as such should probably also be included in the sum.  I always include it in
> the sum, at any rate.

That is what I find odd in the lighting model as there is also an
"ambient_light" global setting. Ambient background light is still diffusely
reflected light, versus an object's own ambience.

--
David Fontaine  <dav### [at] faricynet>  ICQ 55354965
My raytracing gallery:  http://davidf.faricy.net/

Post a reply to this message

Tom Melly wrote:
> 
> "Francois Labreque" <fla### [at] videotronca> wrote in message
> news:3A5DCD94.E1942106@videotron.ca...
> >
> > I personally prefer setting ambient to 0 and let radiosity take care of
> > all this stuff.  But then again, I have the horsepower necessary for it,
> > so ymmv.
> >
> 
> I personally prefer it if people don't rub my nose in the fact that a P90 is
> not the ideal rendering platform - particularily if they're french ;)

Does it help my case if I told you that we share the same Queen?

-- 
Francois Labreque | Unfortunately, there's no such thing as a snooze
    flabreque     | button on a cat who wants breakfast.
        @         |      - Unattributed quote from rec.humor.funny
   videotron.ca

Post a reply to this message

Ron Parker wrote:
> 
> On Thu, 11 Jan 2001 10:06:23 -0500, Francois Labreque wrote:
> >
> >
> >Ron Parker wrote:
> >>
> >> If I were to propose a rule of thumb, I would say ambient and diffuse
> >> should be roughly the same number, and that ambient shouldn't be included
> >> in the requirement that filter+transmit+reflection+diffuse+specular <= 1.
> >
> >Even though, you hint on it in the next paragraph, you should point out
> >that this formula is only valid if you are not using radiosity.
> 
> From a purely theoretical standpoint, I fail to see why this should be
> the case for objects that don't emit their own light (other than the
> reflection/specular thing.)  Could you elaborate?

Sorry, I was refering to the diffuse=ambient part of your statement, not
the rest of the formula, which I agree with.

There.  Better?

-- 
Francois Labreque | Unfortunately, there's no such thing as a snooze
    flabreque     | button on a cat who wants breakfast.
        @         |      - Unattributed quote from rec.humor.funny
   videotron.ca

Post a reply to this message

Tom Melly wrote:
> 
> 3. Don't use ambient, use radiosity. With media. And isosurfaces. On a 386.

In the snow.  Uphills.

-- 
Francois Labreque | Unfortunately, there's no such thing as a snooze
    flabreque     | button on a cat who wants breakfast.
        @         |      - Unattributed quote from rec.humor.funny
   videotron.ca

Post a reply to this message

On Thu, 11 Jan 2001 16:42:22 -0500 Chris Huff wrote:

>I get best results with ambient 0 and radiosity. A high ambient robs the 
>scene of contrast and depth, so the only times I use an ambient other 
>than 0 is when I have a glowing object or have an object that just needs 
>to show up (I sometimes use ambient 1 cylinders aligned along each axis 
>for orientation).

  Chris, do you use the ambient 0 setting with both MegaPOV and the
official POV-Ray?

-- 
Alan - ako### [at] povrayorg - a k o n g <at> p o v r a y <dot> o r g
http://www.povray.org - Home of the Persistence of Vision Ray Tracer

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"Francois Labreque" <fla### [at] videotronca> wrote in message
news:3A5E6795.2FCC0C2B@videotron.ca...
>
> Does it help my case if I told you that we share the same Queen?
>

Going for the sympathy vote, eh?

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In article <dd9t5t02hhqm0l1c19b8onjad5mvvo4b9l@4ax.com>, Alan Kong 
<ako### [at] povrayNO-SPAMorg> wrote:

>   Chris, do you use the ambient 0 setting with both MegaPOV and the
> official POV-Ray?

Yes, when I use the official version (most of my renders are tests of my 
patches or require MP)...but I don't use the radiosity in the official 
version, just a dim (around rgb 0.2 or 0.3) light source at the camera 
position.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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