Hi(gh)!

Am 19.11.2011 00:28, schrieb Robert McGregor:

> Shadows actually /are/ bluish on a sunny day with clear blue sky, and your sky
> is very blue; I think the radiosity is taking that into account, just as in the
> real world.
>
> Try changing your sky color to red and see if you get red shadows...

Of course I know of this... but I would like to create a scene matching 
my *subjective* recalls of bright summer days - even in the 
Mediterranean, I can't remember shadows being THAT blue!

But meanwhile I found out that it's simply because of the missing 
#version 3.7 - after I added this at the beginning of my code, the 
gray_threshold value was taken into account once more!

See you in Khyberspace!

Yadgar

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>
> But my learning curve is very, very flat... when I compare myself to
> those whizkids who know PoV-Ray barely for a year and come up with
> sophisticated scenes, then I really would like to kill not myself (I'm
> even too phlegmatic for suicide!), but to delete all PoV-Ray
> applications and project data and from now on content myself with
> watching TV and drinking cheap canned beer like all the other underclass
> losers do...

Oh, come on - I know we're heading towards winter time, and people all 
over the northern hemisphere are going into hibernation mode (aka 
depression), but please... we just managed to convince Orchid aka 
Invisible that /he/'s not "completely dysfunctional", so don't /you/ 
start now... >_<

Just look at me, for instance. I guess you'd file me under "whizkid", 
with all those code contributions to POV-Ray 3.7, having made radiosity 
easier to use and all that jazz. Guess what - that's just one facet of 
my life you see. The rest of it is probably neither more nor less 
brilliant than anybody else's (including yours). Struggling with 
depressions myself, BTW - been there, done that. (Well, not publicly 
declaring how dysfunctional I am, but anyway...) So I guess I can say 
with some authority of experience: "If you think you suck, I think 
you're sick." (pun intended)

'Nuff said for now. If you're interested in some further advice along 
these lines, feel free to contact me via electionic mail to Christoph at 
Lipka-Koeln in Germany (de).

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> Of course I know of this... but I would like to create a scene matching
> my *subjective* recalls of bright summer days - even in the
> Mediterranean, I can't remember shadows being THAT blue!

But you sky is *much* bluer than the Mediterranean sky! Look at 
photographs, I think you will see the blue hue in the shadows, 
especially on white walls.

Note also that the blue is tempered by all the colors that are 
reflected/refracted from other objects around.

Thomas

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should seriously seek more professional help. We all here can certainly 
try to make you see the bright side of life, and we shall, but that is 
not enough. You may need a little extra support. Whatever you may think, 
keep faith in yourself. Something I can advise in the mean time from 
experience, shut down you PC, forget POV-Ray for a while, take your bike 
(if you have one, else put on good walking shoes) and make big tours, 
without exerting yourself unnecessarily, but putting on a good effort. 
Do that for a week. And think of nothing else, least about yourself. Not 
a cure, but a balm.

Thomas

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=?ISO-8859-1?Q?J=F6rg_=27Yadgar=27_Bleimann?= <yaz### [at] gmxde> wrote:
>
> But my learning curve is very, very flat... when I compare myself to
> [snip]

Whoops!  Comparing yourself to others is generally a bad move.

> Am 18.11.2011 19:26, schrieb Cousin Ricky:
>
> > You can do it again.  Just give it more time and effort.
>
> And that's the problem... I'm not used to giving effort (in any fields
> of life) anymore, effort just HURTS!

   Life is difficult.
                              --the Buddha

   This is a great truth, one of the greatest truths.  It is a great
   truth because once we truly see this truth, we transcend it.  Once
   we know that life is difficult--once we truly understand and accept
   it--then life is no longer difficult.  Because once it is accepted,
   the fact that life is difficult no longer matters.
                              --M. Scott Peck, M.D., _The Road Less Traveled_

> And when I try and try and try and
> even the 22nd attempt is the same failure as the first, then I wonder


This is an example of a "cognitive distortion."  See:
   http://psychcentral.com/lib/2009/15-common-cognitive-distortions/

Find a psychologist who practices cognitive behavioral therapy.  Avoid
psychoanalysis.

I personally have been impressed by your determination over the years.  Please
don't give that up!  Take it from someone who's struggled with clinical
depression for 20 years: as hopeless as your situation may *seem* to you today,
you will not always feel this way.

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> What did I happen to not understand?



You seem to be on the right track. But... well, let me see.

It seems like you forgot to set the material finishes to 0 on your white walls?
Right?
This is the most important step because without it you will never get realistic
bouncing of light off the surfaces.

In that old tutorial I used
finish {
        ambient 0
        diffuse 1

for all materials except the sky sphere.

Sometimes I use diffuse 0.9 or even 0.8 in outdoors situations only, depends on
the situation, but ambient finish should always be 0 when using radiosity.

Another thing, you can never use the same radiosity setting for bot indoors and
outdoors situation. Unless you cheat with fill lights perhaps. But if you want
to mimic real daylight it is not possible. The light on the outside will always
be brighter than the light bouncing inside the room. The outside light is more
direct, while the inside light is mostly indirect. Our eyes will automatically
adjust to this in reality. No camera can take pictures both inside and outside

do it.


inside you have to use two different radiosity settings for each situation.

One tip: try to avoid using colors for surfaces that are 100% white (or 100%
black for that matter) they can never be realistic.

One more thing. The recursion limit of 5 is probably a bit too high for your
scene as you are getting more light in through the windows than in the tutorial.
"recursion limit" controls how many times indirect light bounces off the
surfaces. Where there is little light coming in you typically use higher values
to get more light in you room. Every situation is unique so you may have to try
out a few variations. Too much recursion washes away the contrast, too little
and your scene is too dark. Only do this AFTER you set the material finishes to


Try playing with the balance between "recursion limit" and "brightness".

I usually use recursion limit of 3-5 indoors and 1-3 outdoors.

If you start getting "dirt" or dark smudges on your surfaces, that means you are
on the right track. Those you should be able to get rid of in the final
rendering by raising "count" to 400-600. It takes longer to render but that is
the necessary evil of radiosity.

Hope this helps and happy raytracing.

Hildur K.

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Hi(gh)!

On 13.01.2012 16:29, Hildur K. wrote:


> inside you have to use two different radiosity settings for each situation.

...and as I aim at building consistent worlds which I would like to 
animate, this is a show-stopper! How can I move the camera from inside 
to outside (e. g. through an open door) without getting those weird 
brightness oscillations like with cheap digital cameras in video mode?

> One tip: try to avoid using colors for surfaces that are 100% white (or 100%
> black for that matter) they can never be realistic.
>
> One more thing. The recursion limit of 5 is probably a bit too high for your
> scene as you are getting more light in through the windows than in the tutorial.
> "recursion limit" controls how many times indirect light bounces off the
> surfaces. Where there is little light coming in you typically use higher values
> to get more light in you room. Every situation is unique so you may have to try
> out a few variations. Too much recursion washes away the contrast, too little
> and your scene is too dark. Only do this AFTER you set the material finishes to

>
> Try playing with the balance between "recursion limit" and "brightness".
>
> I usually use recursion limit of 3-5 indoors and 1-3 outdoors.
>
> If you start getting "dirt" or dark smudges on your surfaces, that means you are
> on the right track. Those you should be able to get rid of in the final
> rendering by raising "count" to 400-600. It takes longer to render but that is
> the necessary evil of radiosity.

Thank you for your advice... but meanwhile, Thomas de Groot has provided 
me with some settings which work well both inside and outside... and 
render FAST, the "kitchen" scene takes only about 4 minutes on my Athlon 
64 3500+!

When it comes to animation: is there any way to avoid that strange 
"flickering" of radiosity between the frames?

See you in Khyberspace!

Yadgar

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> ...and as I aim at building consistent worlds which I would like to
> animate, this is a show-stopper! How can I move the camera from inside
> to outside (e. g. through an open door) without getting those weird
> brightness oscillations like with cheap digital cameras in video mode?

And just like our eyes too. Sometimes PovRay shows that our imagination 
is better than real life.

I am pleased that Thomas has come up with a compromise solution.

-- 
Regards
     Stephen

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> Hi(gh)!
>
> On 13.01.2012 16:29, Hildur K. wrote:
>

>> outside and
>> inside you have to use two different radiosity settings for each
>> situation.
>
> ...and as I aim at building consistent worlds which I would like to
> animate, this is a show-stopper! How can I move the camera from inside
> to outside (e. g. through an open door) without getting those weird
> brightness oscillations like with cheap digital cameras in video mode?

Not only cheap cameras you know. Watch any TV documentary and you will 
see brightness adjustments being made while the camera moves from inside 
to out or vice versa. In movies I suspect they avoid this by shooting 
scenes either inside or outside and making the view through the window 
artificial by using a backdrop for instance which they can tune to the 
scene. By the way, there is a method to achieve this brought to us by 
Tim Nikias back in 2005: www.nolights.de using his glare.inc macro for 
creating a backdrop image. His example is the Waiting for Company scene.
>
>
> Thank you for your advice... but meanwhile, Thomas de Groot has provided
> me with some settings which work well both inside and outside... and
> render FAST, the "kitchen" scene takes only about 4 minutes on my Athlon
> 64 3500+!
...And I learned a lot about radiosity in version 3.6 from Hildur! :-)
Good to see you here again once in a while, Hildur!

Thomas

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=?ISO-8859-1?Q?J=F6rg_=27Yadgar=27_Bleimann?= <yaz### [at] gmxde> wrote:
> When it comes to animation: is there any way to avoid that strange
> "flickering" of radiosity between the frames?

The +HR command line switch in 3.7 may help with this.  I haven't tried it
myself, so you'll have to experiment.

You are, of course, using -J for anti-aliasing.  (That actually hasn't worked
for me in 3.7, but Christoph hasn't reproduced the problem.)

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