Hi,

I was wondering if it is possible to use skies.inc to create a trace using
only a single background? I just want a background of a sky only (no
earth/ground) but it looks like most of the examples have both a sky and
ground portion...

Thanks a lot.

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In article <web.3fb804b41087588a204769940@news.povray.org>,
 "cg-hci_novice" <nomail@nomail> wrote:

> I was wondering if it is possible to use skies.inc to create a trace using
> only a single background? I just want a background of a sky only (no
> earth/ground) but it looks like most of the examples have both a sky and
> ground portion...

Just remove the ground. Of course, this won't be very realistic, since 
in the real world you do have a ground...probably better to just point 
the camera up.

-- 
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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Christopher James Huff wrote:
>In article <web.3fb804b41087588a204769940[at]news.povray.org>,
> "cg-hci_novice" <nomail[at]nomail> wrote:
>
>> I was wondering if it is possible to use skies.inc to create a trace using
>> only a single background? I just want a background of a sky only (no
>> earth/ground) but it looks like most of the examples have both a sky and
>> ground portion...
>
>Just remove the ground. Of course, this won't be very realistic, since
>in the real world you do have a ground...probably better to just point
>the camera up.

No, my intention is not for this trace to be 100% realistic.

I tried removing the ground, however, this seems possible only with the
pigments.
I would like to use S_Cloud2 sky sphere since all the others are rather dark
for the effect I want but not sure how I can just use the top or bottom
half of it (would prefer to use the bottom half) (?)

Would appreciate any suggestions to do this.

Thank you for your help.


>
>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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OK I got it,
The pigment used by S_Cloud2 is a gradient y one: value increases from  0 at
y=0 to 1 at y=1 ( assuming it is not scaled) then falls to 0 at y>1
increasing again to 1 at y=2 and so on
the value describes a sawtooth patern as you can see on this image
http://users.skynet.be/bs936509/povfr/materiaux/mat-mot-geo-01.htm
so value is 1 at y <0.
It is a new behaviour of gradient in POV 3.5
try using planar instead

#declare S_Cloud2 =
sky_sphere {
    pigment {planar
        pigment_map {
            [0.00 rgb <0.847, 0.749, 0.847> ] // horizon
            [0.10 SkyBlue ]                   // horizon
            [0.20 P_Cloud4 ]
        }
    }
}


HTH

Marc

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Marc Jacquier wrote:
>OK I got it,
>The pigment used by S_Cloud2 is a gradient y one: value increases from  0 at
>y=0 to 1 at y=1 ( assuming it is not scaled) then falls to 0 at y>1
>increasing again to 1 at y=2 and so on
>the value describes a sawtooth patern as you can see on this image
>http://users.skynet.be/bs936509/povfr/materiaux/mat-mot-geo-01.htm
>so value is 1 at y <0.
>It is a new behaviour of gradient in POV 3.5
>try using planar instead
>
>#declare S_Cloud2 =
>sky_sphere {
>    pigment {planar
>        pigment_map {
>            [0.00 rgb <0.847, 0.749, 0.847> ] // horizon
>            [0.10 SkyBlue ]                   // horizon
>            [0.20 P_Cloud4 ]
>        }
>    }

Yes, this helps. Thanks for the tip.
>}
>
>
>HTH
>
>Marc
>

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