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...his painting, the canvas is not even dry and the artist and his models
went out for dinner.
Well, but the raytraced reproduction is far away from being finished.
This is just the first test with HQ radiosity settings.
global_settings {
assumed_gamma 1.0
max_trace_level 16
radiosity {
count 1600
error_bound 0.15
recursion_level 4
...
[everything else is the same as the indoor HQ settings from rad_def.inc]
The problems are:
Some ugly bright spots on the walls. Especially near the virginals and
windows. They appear ONLY when layerd textures are used. Indeed
the top layer uses an agate pigment and the shape of these spots is similar
to that pattern but in fact due to the pattern, these parts should appear
a little bit darker than the surrounding.
When using some glass material for the windows (indeed for this render
there is no glass used) even a very simple glass, the wall at the window side
becomes completely black. To be more exact, the part of the wall facing
the room.
The image maps (used for the paintings) become sudden black at a certain
level of darkness. So they look very ugly and be sure, the original maps I
have used are smooth.
All above mentioned does not appear with lower quality settings for radiosity
(e.g count 400, error_bound 0.8) and also not when using normal light sources.
Have I missed something?
Or are these known limitations for the way radiosity is done by POV?
Or is there something goin' wrong with the radiosity samples calculated
by POV (in other words: are there BUGS)?
Has anybody of the more experienced radiosity users any hints, explanations
or whatever? I'm really stuck and with HQ radiosity the image needs days
to render so it's no fun to work with trial and error.
And here is something completely different but quite interesting.
For this image you are standing close to the rear wall behind the place Vermeer
was sitting, so you can see the easel. The dimension for the room was reconstructed
by what can be seen in the mirror. (In the original painting you see the edge of the
table, so you can calculate the angle the mirror is hanging on the wall and
you can also see the part where the rear wall meets the floor and now you can
calculate the length of the room.) So we know the length of the wall at the window
side and we see that there is exactly room for a third window of the same size as
already seen in the painting. Also I assume that Vermeer would not have placed
his easel in the darkest place of the room and there it would be if there is not a
third
window.
BUT the lighting as seen in the painting (especially on the rug covering the table)
looks more like there is NOT a third window. (Or lets say the window shades
are closed.) In the image I have attached there is a third window but I have also
done a radiosity simulation without the third window and the lighting is much closer
to what can be seen in the painting.
What does this mean? Has Vermeer closed the window shades because he preferred
this kind of lighting for the room even if this means his canvas was lit very poor?
Or did he close the window shades, looked at the room, opened them to do some
brush strokes, closed them again...
-Ive
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Attachments:
Download 'MusicLesson.jpg' (75 KB)
Preview of image 'MusicLesson.jpg'
![MusicLesson.jpg](/povray.binaries.images/attachment/%3C3da07987%40news.povray.org%3E/MusicLesson.jpg?preview=1)
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Truly remarkable.
Fabien.
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Beautiful!
/Ib
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Beautiful job, I can't believe you were able to reconstruct the room
dimensions. Marvelous!
Ive wrote:
> ...his painting, the canvas is not even dry and the artist and his models
> went out for dinner.
>
> Well, but the raytraced reproduction is far away from being finished.
> This is just the first test with HQ radiosity settings.
>
>
> global_settings {
> assumed_gamma 1.0
> max_trace_level 16
> radiosity {
> count 1600
> error_bound 0.15
> recursion_level 4
> ...
> [everything else is the same as the indoor HQ settings from rad_def.inc]
>
>
> The problems are:
>
> Some ugly bright spots on the walls. Especially near the virginals and
> windows. They appear ONLY when layerd textures are used. Indeed
> the top layer uses an agate pigment and the shape of these spots is similar
> to that pattern but in fact due to the pattern, these parts should appear
> a little bit darker than the surrounding.
>
> When using some glass material for the windows (indeed for this render
> there is no glass used) even a very simple glass, the wall at the window side
> becomes completely black. To be more exact, the part of the wall facing
> the room.
>
> The image maps (used for the paintings) become sudden black at a certain
> level of darkness. So they look very ugly and be sure, the original maps I
> have used are smooth.
>
> All above mentioned does not appear with lower quality settings for radiosity
> (e.g count 400, error_bound 0.8) and also not when using normal light sources.
>
> Have I missed something?
> Or are these known limitations for the way radiosity is done by POV?
> Or is there something goin' wrong with the radiosity samples calculated
> by POV (in other words: are there BUGS)?
>
> Has anybody of the more experienced radiosity users any hints, explanations
> or whatever? I'm really stuck and with HQ radiosity the image needs days
> to render so it's no fun to work with trial and error.
>
>
> And here is something completely different but quite interesting.
> For this image you are standing close to the rear wall behind the place Vermeer
> was sitting, so you can see the easel. The dimension for the room was reconstructed
> by what can be seen in the mirror. (In the original painting you see the edge of the
> table, so you can calculate the angle the mirror is hanging on the wall and
> you can also see the part where the rear wall meets the floor and now you can
> calculate the length of the room.) So we know the length of the wall at the window
> side and we see that there is exactly room for a third window of the same size as
> already seen in the painting. Also I assume that Vermeer would not have placed
> his easel in the darkest place of the room and there it would be if there is not a
third
> window.
> BUT the lighting as seen in the painting (especially on the rug covering the table)
> looks more like there is NOT a third window. (Or lets say the window shades
> are closed.) In the image I have attached there is a third window but I have also
> done a radiosity simulation without the third window and the lighting is much closer
> to what can be seen in the painting.
> What does this mean? Has Vermeer closed the window shades because he preferred
> this kind of lighting for the room even if this means his canvas was lit very poor?
> Or did he close the window shades, looked at the room, opened them to do some
> brush strokes, closed them again...
>
> -Ive
>
>
>
>
Post a reply to this message
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another one for E:\Art :)
cu!
--
camera{location-z*3}#macro G(b,e)b+(e-b)*(C/50)#end#macro L(b,e,k,l)#local C=0
;#while(C<50)sphere{G(b,e),.1pigment{rgb G(k,l)}finish{ambient 1}}#local C=C+1
;#end#end L(y-x,y,x,x+y)L(y,-x-y,x+y,y)L(-x-y,-y,y,y+z)L(-y,y,y+z,x+y)L(0,x+y,
<.5,1,.5>,x)L(0,x-y,<.5,1,.5>,x) // ZK http://www.povplace.be.tf
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3da07987@news.povray.org...
> All above mentioned does not appear with lower quality settings for
radiosity
> (e.g count 400, error_bound 0.8) and also not when using normal light
sources.
For the black spots, you could try a higher max_trace_level. That should do
it, but of course transparent material are always difficult to manage with
radiosity (you can also try loading a rad file created with the scene
without the transparent stuff).
The bright spots are perhaps a coincidence problem. Try to "sink" the window
frames slightly into the wall, at least it worked for me once.
Still, you've gone amazingly far in the recreation of the scene without
major visible problems... Bravo !
> What does this mean? Has Vermeer closed the window shades because he
preferred
> this kind of lighting for the room even if this means his canvas was lit
very poor?
> Or did he close the window shades, looked at the room, opened them to do
some
> brush strokes, closed them again...
The 3rd shades surely look as if they were closed (or draped). Actually this
is certainly the case in his other paintings.
http://gallery.euroweb.hu/art/v/vermeer/03b/23conce.jpg
http://gallery.euroweb.hu/art/v/vermeer/03c/25artpa.jpg
http://gallery.euroweb.hu/art/v/vermeer/02b/08offic.jpg
http://gallery.euroweb.hu/art/v/vermeer/03a/17lute.jpg
I don't think the lack of light was such a problem anyway. I guess that such
paintings took days to create, so it's not like he had only a few seconds to
"capture the moment". It's painting, not photography ! The "Art of painting"
image gives some hints about the creative use of draping (though it could be
said the drape was in fact imaginary and used only for dramatic purpose, as
in http://gallery.euroweb.hu/art/v/vermeer/04/33faith.jpg)
G.
--
**********************
http://www.oyonale.com
**********************
- Graphic experiments
- POV-Ray and Poser computer images
- Posters
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OK, *now* I'm amazed... Nothing I ever got out of POV-Ray looked this good!
Andrew.
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Thanks a lot to all.
I think the next step (beside of playin' more with radiosity) is to create
the dresses for the girl and her teacher. I've never thought that I will
become a tailor by using POV some day.
And one more thing to the room dimensions. For sure, they are
hypothetical and I still do not know the exact position for the right wall.
But somehow I believe there is a door somewhere. But that's also
purely hypothetical.
-Ive
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"Ive" <ive### [at] lilysoft com> wrote in news:3da07987@news.povray.org
Realy nice :)
Imho it is a shame to waste some of tihs nice image details in .jpg
compression, how about posing lossless compressed version (i.e. png) ?
--
#macro g(U,V)(.4*abs(sin(9*sqrt(pow(x-U,2)+pow(y-V,2))))*pow(1-min(1,(sqrt(
pow(x-U,2)+pow(y-V,2))*.3)),2)+.9)#end#macro p(c)#if(c>1)#local l=mod(c,100
);g(2*div(l,10)-8,2*mod(l,10)-8)*p(div(c,100))#else 1#end#end light_source{
y 2}sphere{z*20 9pigment{function{p(26252423)*p(36455644)*p(66656463)}}}//M
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> The bright spots are perhaps a coincidence problem. Try to "sink" the window
> frames slightly into the wall, at least it worked for me once.
>
Yes, I have also made the experience that it is better to let the objects more
intersect for radiosity scenes. But for some reason, I have forgotten to do this
with the window frames.
But this will not solve the problems for the rear wall near the virginals. And why
does this only happen with layered textures?
Somehow I've got the impression that something is going wrong with the radiosity
calculation when pigments with high transmit/filter values (like glass or texture
layers) are involved.
But I think before complaining, I should try a version with a high max_trace_level
first, let's see what will happen.
Anyway, thanks a lot.
-Ive
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