distance forsky dome

Hello, Radiance-general.

For making material, ‘’Picture Perfect RGB Rendering Using Prefiltering and Sharp Color Primaries’’ is very helpful for me.

Now I have another problem.

I’d like to make sky dome that material depend on sky distribution measured 145 points. These 145 points relate to CIE IDMP. I think the best way is to make it by using “brightfunc” and “source” which has o distance. But this is very difficult way for me. Then I made it by using square*145 by “polygon”. I know this way give sky distance. Maybe distance between room and sky is important.

When the radius of sky dome was changed so that indoor (1.5m * 1.2*1.3m) illuminance by rtrace might become suitable, the almost same value as an actual measurement was acquired in the radius of 200m.But rendered picture is not good.
Giving sky material ;

void glow sky_1
0
4 luminance/179 luminance/179 luminance/179 0

…*145.

I have some questions.
1: When I make sky dome, is to use “polygon”that have distance suitable? 2: Supposing that is right, is there any suitable radius to sky dome?
3;And for material of sun,is "lumiance/179" suitable??

I’m confusing…Please give advice.

Kouichi kobayashi
Tokyo University of Science

···

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just about rendering quality,

I suggest you to use "light" instead "glow",
consider window with mkillum (generate light distribution for windows pol.),
use them like emitters without the sky....
(or with a fake overcast/intermediate or clear sky outside, just for
rendering)

cheers,
giulio

PS about radii dimension you should take into account parallax errors (two
points in your model, both looking north, and intersecting in different
places the sky dome: less this angle, better it is...)

···

-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: 18 November 2003 15:06
To: [email protected]
Subject: [Radiance-general] distance forsky dome

Hello, Radiance-general.

For making material, ‘’Picture Perfect RGB Rendering Using Prefiltering
and Sharp Color Primaries’’ is very helpful for me.

Now I have another problem.

I’d like to make sky dome that material depend on sky distribution
measured 145 points. These 145 points relate to CIE IDMP. I think the best
way is to make it by using “brightfunc” and “source” which has o
distance. But this is very difficult way for me.
Then I made it by using square*145 by “polygon”. I know this way give sky
distance. Maybe distance between room and sky is important.

When the radius of sky dome was changed so that indoor (1.5m * 1.2*1.3m)
illuminance by rtrace might become suitable, the almost same value as an
actual measurement was acquired in the radius of 200m.But rendered picture
is not good.
Giving sky material ;

void glow sky_1
0
0
4 luminance/179 luminance/179 luminance/179 0

…*145.

I have some questions.
1: When I make sky dome, is to use “polygon”that have distance suitable?
2: Supposing that is right, is there any suitable radius to sky dome?
3;And for material of sun,is "lumiance/179" suitable??

I’m confusing…Please give advice.

Kouichi kobayashi
Tokyo University of Science

_________________________________________________________________
あなたのPCを守るために定期的なセキュリティ対策を。マイクロソフト セキュリ
ティ情報センター http://www.microsoft.com/japan/protect/hm.asp

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Hello Kouichi,

I think the best way is using Brightdata or Colordata. I know these take a
data file as input, but I`ve never tried them myself.

another problem is the value measured at sun`s position. As I understood
your method, you`d be modeling the sun with a polygon of greater area than
the real sun, but with the same luminance, which will produce excessive
illuminance. One solution could be to use an average value over the surface
(difficult to calculate) so you`d get correct illuminance but wrong
luminances... or am I missing something? Probably someone with more
experience can correct me here.

Santiago

···

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of 小林 紘

Sent: Wednesday, November 19, 2003 12:06 AM
To: [email protected]
Subject: [Radiance-general] distance forsky dome

Hello, Radiance-general.

For making material, ‘’Picture Perfect RGB Rendering Using Prefiltering
and Sharp Color Primaries’’ is very helpful for me.

Now I have another problem.

I’d like to make sky dome that material depend on sky distribution
measured 145 points. These 145 points relate to CIE IDMP. I think
the best
way is to make it by using “brightfunc” and “source” which has o
distance. But this is very difficult way for me.
Then I made it by using square*145 by “polygon”. I know this
way give sky
distance. Maybe distance between room and sky is important.

When the radius of sky dome was changed so that indoor (1.5m * 1.2*1.3m)
illuminance by rtrace might become suitable, the almost same value as an
actual measurement was acquired in the radius of 200m.But
rendered picture
is not good.
Giving sky material ;

void glow sky_1
0
0
4 luminance/179 luminance/179 luminance/179 0

…*145.

I have some questions.
1: When I make sky dome, is to use “polygon”that have distance
suitable?
2: Supposing that is right, is there any suitable radius to sky dome?
3;And for material of sun,is "lumiance/179" suitable??

I’m confusing…Please give advice.

Kouichi kobayashi
Tokyo University of Science

_________________________________________________________________
あなたのPCを守るために定期的なセキュリティ対策を。マイクロソフト セキュリ
ティ情報センター http://www.microsoft.com/japan/protect/hm.asp

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Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

Hi 小林 紘一 !

I’d like to make sky dome that material depend on sky distribution
measured 145 points. These 145 points relate to CIE IDMP. I think the best
way is to make it by using “brightfunc” and “source” which has o
distance. But this is very difficult way for me.

I suggest you to read John Mardaljevic's PhD Thesis,
especially his work about daylight coefficients:

http://www.iesd.dmu.ac.uk/~jm

Hope this helps!

···

--
Francesco Anselmo
[email protected]
[email protected]

Kouichi,

The material here should help you out:

- Chapter 3 (Section 3.2)
- Chapter 6 (section 6.2)

Download PDFs from http://www.iesd.dmu.ac.uk/~jm/zxcv-thesis/

-John

···

-----------------------------------------------
Dr. John Mardaljevic
Senior Research Fellow
Institute of Energy and Sustainable Development
De Montfort University
The Gateway
Leicester
LE1 9BH, UK
+44 (0) 116 257 7972
+44 (0) 116 257 7981 (fax)

[email protected]
http://www.iesd.dmu.ac.uk/~jm

Thanks,everyone.
I'll try them as soon as possible.

If I would have any further question,I might ask you again.

Regards,

Kouichi Kobayashi
Senior
Tokyo University of Science

···

_________________________________________________________________
あなたのPCを守るために定期的なセキュリティ対策を。マイクロソフト セキュリ
ティ情報センター http://www.microsoft.com/japan/protect/hm.asp