YA reflective sphere on a checkered plane.. at least, that was the
original idea. It quickly morphed into some kind of radiosity pic before
eventually becoming this. (Post-processing was done in Photoshop to
brighten up the pic.)

My intent was to make this an early morning scene. Unfortunately, while
the sky works well for this, the lighting itself seems strongly
reminiscent of late afternoon! (At least, to me and a lot of other
people who've seen it.) I have no idea how to fix this; quick tests in
Photoshop to add brighter/dimmer/cooler light only made the lighting
look strange. I suppose I should be happy that the lighting is
convincing enough to suggest *any* particular time of day, but I would
be happier with the one that I was aiming for. ;)

A couple notes on radiosity settings: first, the only light_source is a
"sun" placed well outside the room, and the count for this image was
only 100. I achieved this level of smoothness with a high error_bound
and a low low_error_factor (1 and .1, respectively). More testing is
needed to determine if this method can replace typical low error_bound
radiosity settings in other situations, unless someone's already done
some and I missed it, but I'll let someone with a faster computer than
mine do that testing! Second, judging from the color bleed on the floor,
it appears that radiosity "bounces" off of reflective surfaces; is this
true? Third, you can see the back of the room is full of artifacts; I
don't know if this is because of poor lighting, or because the radiosity
data in the reflected image is only a crude approximation.

I'll probably keep working on this; it would make a pretty cool scene
with window glass, blinds, pictures on the walls, maybe a ceiling fan,
and gods know what (a table, maybe?) in the middle, even if most of it
would only be visible in the reflection. Okay, I'll shut up and let you
see the pic now.. comments welcome as usual.

-Xplo

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Attachments:
Download 'rbml-c2-edit.jpg' (46 KB)

Preview of image 'rbml-c2-edit.jpg'

its beautiful! It does feel like morning to me.


Gary

Xplo Eristotle <inq### [at] unforgettablecom> wrote in message
news:3BFF76A6.F83284F6@unforgettable.com...
> YA reflective sphere on a checkered plane.. at least, that was the
> original idea. It quickly morphed into some kind of radiosity pic before
> eventually becoming this. (Post-processing was done in Photoshop to
> brighten up the pic.)
>
> My intent was to make this an early morning scene. Unfortunately, while
> the sky works well for this, the lighting itself seems strongly
> reminiscent of late afternoon! (At least, to me and a lot of other
> people who've seen it.) I have no idea how to fix this; quick tests in
> Photoshop to add brighter/dimmer/cooler light only made the lighting
> look strange. I suppose I should be happy that the lighting is
> convincing enough to suggest *any* particular time of day, but I would
> be happier with the one that I was aiming for. ;)
>
> A couple notes on radiosity settings: first, the only light_source is a
> "sun" placed well outside the room, and the count for this image was
> only 100. I achieved this level of smoothness with a high error_bound
> and a low low_error_factor (1 and .1, respectively). More testing is
> needed to determine if this method can replace typical low error_bound
> radiosity settings in other situations, unless someone's already done
> some and I missed it, but I'll let someone with a faster computer than
> mine do that testing! Second, judging from the color bleed on the floor,
> it appears that radiosity "bounces" off of reflective surfaces; is this
> true? Third, you can see the back of the room is full of artifacts; I
> don't know if this is because of poor lighting, or because the radiosity
> data in the reflected image is only a crude approximation.
>
> I'll probably keep working on this; it would make a pretty cool scene
> with window glass, blinds, pictures on the walls, maybe a ceiling fan,
> and gods know what (a table, maybe?) in the middle, even if most of it
> would only be visible in the reflection. Okay, I'll shut up and let you
> see the pic now.. comments welcome as usual.
>
> -Xplo


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

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Xplo Eristotle wrote:
> 
> My intent was to make this an early morning scene. Unfortunately, while
> the sky works well for this, the lighting itself seems strongly
> reminiscent of late afternoon! (At least, to me and a lot of other
> people who've seen it.) I have no idea how to fix this; quick tests in
> Photoshop to add brighter/dimmer/cooler light only made the lighting
> look strange. I suppose I should be happy that the lighting is
> convincing enough to suggest *any* particular time of day, but I would
> be happier with the one that I was aiming for. ;)

I think the clouds look good, but a bit too red.  Some media could be good
for morning atmosphere too.

> A couple notes on radiosity settings: first, the only light_source is a
> "sun" placed well outside the room, and the count for this image was
> only 100. I achieved this level of smoothness with a high error_bound
> and a low low_error_factor (1 and .1, respectively). More testing is
> needed to determine if this method can replace typical low error_bound
> radiosity settings in other situations, unless someone's already done
> some and I missed it, but I'll let someone with a faster computer than
> mine do that testing!

Hmm, it looks really quite accurate for error_bound 1, but i am not sure
if it's a very good method. What recursion_limit did you use? Have you
tried varying pretrace_end?

> Second, judging from the color bleed on the floor,
> it appears that radiosity "bounces" off of reflective surfaces; is this
> true? 

Yes, somehow. Reflection is calculated for radiosity samples.

> Third, you can see the back of the room is full of artifacts; I
> don't know if this is because of poor lighting, or because the radiosity
> data in the reflected image is only a crude approximation.

I'm not sure, but such a scene seems a quite difficult setup for radiosity
in general.  How does it look with more conventional radiosity settings?

> I'll probably keep working on this; it would make a pretty cool scene
> with window glass, blinds, pictures on the walls, maybe a ceiling fan,
> and gods know what (a table, maybe?) in the middle, even if most of it
> would only be visible in the reflection. Okay, I'll shut up and let you
> see the pic now.. comments welcome as usual.
> 

It looks nice, my submission for the 10best cover image contest has a
similar configuration (but a bit different lighting) and i was forced to
use fairly low radiosity settings because it was that slow.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

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"Xplo Eristotle" <inq### [at] unforgettablecom> wrote in message
news:3BFF76A6.F83284F6@unforgettable.com...
>
> My intent was to make this an early morning scene. Unfortunately, while
> the sky works well for this, the lighting itself seems strongly
> reminiscent of late afternoon! (At least, to me and a lot of other
> people who've seen it.) I have no idea how to fix this; quick tests in
> Photoshop to add brighter/dimmer/cooler light only made the lighting
> look strange. I suppose I should be happy that the lighting is
> convincing enough to suggest *any* particular time of day, but I would
> be happier with the one that I was aiming for. ;)

Yellower sunlight for morning, yellow-orange for late afternoon pre-evening.
That's my thinking on it.  And of course both can actually be quite
orange-red too if the sun is at horizon.  The colors of sunlight is a rather
important thing to consider.

> A couple notes on radiosity settings: first, the only light_source is a
> "sun" placed well outside the room, and the count for this image was
> only 100. I achieved this level of smoothness with a high error_bound
> and a low low_error_factor (1 and .1, respectively). More testing is
> needed to determine if this method can replace typical low error_bound
> radiosity settings in other situations, unless someone's already done
> some and I missed it, but I'll let someone with a faster computer than
> mine do that testing! Second, judging from the color bleed on the floor,
> it appears that radiosity "bounces" off of reflective surfaces; is this
> true? Third, you can see the back of the room is full of artifacts; I
> don't know if this is because of poor lighting, or because the radiosity
> data in the reflected image is only a crude approximation.

You're probably forgetting about using higher max_trace_level.  I've used
error_bound 1 before and thought it did well depending on the scene.
The back wall isn't what distracts me, it's the edges of wall and floor.

bob h

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"Bob H." <omn### [at] msncom> wrote in message
news:3bff9fc2$1@news.povray.org...
> Yellower sunlight for morning, yellow-orange for late afternoon
pre-evening.
> That's my thinking on it.

Actually I feel that the sunlight tends to be whiter/grayer in the morning
whilst the sun is very red.

Mick

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I also meant to say it is cooler in the mornings with less dust in the air.

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Christoph Hormann wrote:
> 
> Xplo Eristotle wrote:
> >
> > A couple notes on radiosity settings: first, the only light_source is a
> > "sun" placed well outside the room, and the count for this image was
> > only 100. I achieved this level of smoothness with a high error_bound
> > and a low low_error_factor (1 and .1, respectively). More testing is
> > needed to determine if this method can replace typical low error_bound
> > radiosity settings in other situations, unless someone's already done
> > some and I missed it, but I'll let someone with a faster computer than
> > mine do that testing!
> 
> Hmm, it looks really quite accurate for error_bound 1, but i am not sure
> if it's a very good method. What recursion_limit did you use? Have you
> tried varying pretrace_end?

recursion_limit 2, and no. As I said, my computer is slow, which
discourages extensive testing. I'll probably do some spot testing (maybe
in that top corner) later, but the current settings are good enough to
work with.

> I'm not sure, but such a scene seems a quite difficult setup for radiosity
> in general.  How does it look with more conventional radiosity settings?

Like any other room lit mostly by radiosity: lots of artifacts, even on
flat surfaces.

> It looks nice, my submission for the 10best cover image contest has a
> similar configuration (but a bit different lighting) and i was forced to
> use fairly low radiosity settings because it was that slow.

The radiosity is the only slow thing in my scene; without it, this image
would render in a couple of minutes, rather than several hours.

-Xplo

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"Bob H." wrote:
> 
> You're probably forgetting about using higher max_trace_level.  I've used
> error_bound 1 before and thought it did well depending on the scene.

What effect would that have? I only have one reflective object in the
scene. (Well, technically, three, but the other two aren't really
obvious.) AFAIK, max_trace_level has no direct effect on radiosity.

-Xplo

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It does have. Try setting it to 2 and you'll see (your recursion limit will
be lowered to 1).
Max_trace_level 1 disables radiosity at all...

--
Jonathan.
"Xplo Eristotle" <inq### [at] unforgettablecom> ha scritto nel messaggio
news:3C0014B8.D5F39AFE@unforgettable.com...
> "Bob H." wrote:
> >
> > You're probably forgetting about using higher max_trace_level.  I've
used
> > error_bound 1 before and thought it did well depending on the scene.
>
> What effect would that have? I only have one reflective object in the
> scene. (Well, technically, three, but the other two aren't really
> obvious.) AFAIK, max_trace_level has no direct effect on radiosity.
>
> -Xplo

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JRG wrote:
> 
> It does have. Try setting it to 2 and you'll see (your recursion limit will
> be lowered to 1).
> Max_trace_level 1 disables radiosity at all...

So, assuming I've left it at the default of 5, and have a
recursion_limit of 2, what effect would it have again to raise the max_trace_level?

-Xplo

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