I am working on a starship simulation project and one of the things I am
simulating is sensors, including visible light (eg camera/viewscreen).  Part of
my simulation includes generating a planetary system (a star and a collection of
planets and moons in orbit).  I am using povray to to generate a camera
(viewscreen) image.  I would like to do two things that are not clearly outlined
in the documentation that comes with the docs for POV-Ray I install on my Ubuntu
18.04 Linux system (version 3.7.0).  One is to create a "sky sphere" containing
a starfield and the other is to create a light source for the "star" at the
center of the planetary system.  I would like the shadows to be realistly sharp
(posibly allowing some "fuzzyness" for planets with atmospheres).  Has anyone
used POV-Ray to do this and if so, what are the recogmendations.

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Le 2022-06-10 à 12:40, Robert Heller a écrit :
> I am working on a starship simulation project and one of the things I am
> simulating is sensors, including visible light (eg camera/viewscreen).  Part of
> my simulation includes generating a planetary system (a star and a collection of
> planets and moons in orbit).  I am using povray to to generate a camera
> (viewscreen) image.  I would like to do two things that are not clearly outlined
> in the documentation that comes with the docs for POV-Ray I install on my Ubuntu
> 18.04 Linux system (version 3.7.0).  One is to create a "sky sphere" containing
> a starfield and the other is to create a light source for the "star" at the
> center of the planetary system.  I would like the shadows to be realistly sharp
> (posibly allowing some "fuzzyness" for planets with atmospheres).  Has anyone
> used POV-Ray to do this and if so, what are the recogmendations.
> 

The light from that central star only need a simple point light 
surrounded by the body of the star as a looks_like object.
Sample :
light_source{0, rgb StarColour*10 //make it pretty bright.
    looks_like{
        sphere{0 100
               pigment{rgb StarColour}
               finish{emission 1}// make it self illuminated
         }
    }
}

The lone zero get expanded to <0,0,0>.
The part after «rgb» can be changed to any colour you want, such as :
rgb<1, 5, 20>/*a blue star*/
rgb<3, 1, 0.2>/*a red dwarf*/

For the planets with an atmosphere, you should use two concentric 
spheres. One with an opaque pigment for the surface, and a transparent 
one with the hollow option to contain some scattering media to simulate 
the atmosphere.
For a gas giant, don't use the inner sphere, just increase the media's 
density.

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"Robert Heller" <hel### [at] deepsoftcom> wrote:
>  Part of
> my simulation includes generating a planetary system (a star and a collection of
> planets and moons in orbit).
>  Has anyone
> used POV-Ray to do this and if so, what are the recogmendations.

Of course.  Use the Search feature in the toolbar, or your favorite search
engine + keyword POVRay, and you will find loads.

Search for terms like Solar System, Planet, Earth, Moon, Spaceship, Galaxy, Sun,
StarField, etc.  Lots of work, including a (then) custom version of POV-Ray to
support the scales needed to render Larry Niven's RingWorld.

SO much has been discussed, that it's hardly worth addressing here (yet), until
you've had time to peruse and digest it all, and see if you have any specific
questions after you start playing with the project and have some sample code and
test renders.

So - you're lucky.   :D ;)

- Bill

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