Emulating sunlight and skylight

Emulating sunlight and skylight

Post by Kim Therke » Fri, 24 Oct 2003 22:03:34


Hi!

I am trying to render a photo realistic outdoor scene where the sky is not
visible but I still need spectras for the sun and sky to emulate the light
coming from them. I have emulated the sun as directional light and the
skylight as a dome using an area light source.
The problem is that I don't know how to combine the light from the sun and
sky in a realistic way. Can you get a seperate spectrum for the sun and the
rest of the sky?

Does anyone know where to find some good material about these issues?

Best Regards
Kim Therkelsen
 
 
 

Emulating sunlight and skylight

Post by drhowarddr » Fri, 24 Oct 2003 23:19:58

I don't have material off hand but one hint is from photography where the
sun is considered to be 5500 deg K but shadows are considered to be lit only
by the sky at a lower temperature.

 
 
 

Emulating sunlight and skylight

Post by Jens Kilia » Sat, 25 Oct 2003 23:07:47

"Kim Therkelsen" < XXXX@XXXXX.COM > writes:

You could try Radiance ( http://www.yqcomputer.com/ ).
--
mailto: XXXX@XXXXX.COM phone:+49-7031-464-7698 (TELNET 778-7698)
http://www.yqcomputer.com/ ~jjk/ fax:+49-7031-464-7351
As the air to a bird, or the sea to a fish,
so is contempt to the contemptible. [Blake]
 
 
 

Emulating sunlight and skylight

Post by Miston Dri » Sun, 26 Oct 2003 04:25:55


Look for a paper titled "A Practical Analytic Model for Daylight" by A.
J. Preetham, Peter Shirley & Brian Smiths.


Regards
Drirr.
 
 
 

Emulating sunlight and skylight

Post by Kim Therke » Mon, 27 Oct 2003 06:17:14

Thank you for your answer. I found the paper you mention briefly after
having send my question to this newsgroup. I has been quite useful to me.
My strategy is now to use the CIE luminance formula to get the intensity of
the light and then multiply it to an average spectral power distribution for
a sunny summers day.
I guess it is the same approach as used in the Radiance system.

Best Regards
Kim Therkelsen





not
light
and
the