In article <web.3fc69a25b2b1540cca01221d0@news.povray.org>,
 "incognito" <nomail@nomail> wrote:

> >You sure he said to do that? The usual arrangement has things the other
> >way around. Light sources, even area lights, are very bad at doing
> >diffuse light coming from large areas, such as a sky. Radiosity is very
> >bad at doing light coming from more or less a single point. Radiosity
> >for the sky and an area light for the sun would make much more sense.
> >And if he said to use a light source, it wasn't pure radiosity.
> >
> If it clarifies any, here is the assignment:
> 
> http://www.evl.uic.edu/aej/488/fall2k3.hw4.html

Hmm...some apparent misconceptions. Radiosity is a lighting algorithm, 
not a rendering algorithm, and POV-Ray *always* raytraces. With POV, you 
can raytrace a scene with conventional lighting or monte-carlo radiosity 
(which itself uses raytracing to take the radiosity samples), but you 
usually use radiosity to complement ordinary lighting.

An orrery is a poor structure to use for demonstrating radiosity. The 
planets will not reflect a visible amount of light on each other, will 
only have a slight influence on their moons, and it is a very 
inefficient way to simulate the sun. Radiosity will only benefit the 
rest of the scene, which is apparently secondary to the project. A 
typical example of a radiosity scene would be an outdoor structure with 
lots of shadows or a room with sunlight pouring in through a window.


> I just did this and it was not too dim. I think it does seem to be acting as
> a light source now just maybe not very noticeable because I do have a
> relatively light background. (My background ambient is set to only 0.4 and
> the sun is set to ambient 1). I will go ahead and try the diffuse at a
> higher value too since I would like it to be more noticeable.

Ah...increasing diffuse will just make the scene brighter, it won't make 
the sun contribute more. You don't get much light from the sun becase it 
isn't much brighter than the sky...it is only a little more than twice 
as bright. The light from your sun does fall off with distance, which 
makes it insignificant compared to the light from the sky. Use a much 
higher ambient value for the sun, and it will shine brighter. Dimming 
the sky will make the effect more pronounced.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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