"Phil Cook" <phi### [at] deckingdealscouk> wrote in message
news:oprwfbhgleeybzwd@news.povray.org...
>
> I model a lot of outdoor stuff and use the excellent SunPos macro to
> calculate the position of the sun. I would like to animate this by
> altering the sun's position, this of course I can do easily, however the
> sky_sphere colour won't match the sun position( blue sky at sunset etc.)
>
> Using the old adage of try and work it out yourself, I have written a
> little macro that seems to solve this. Before I get too involved with it,
> altering light colour and creating a much better sun, I would really like
> to get some comments as to my script and the colours used.

Looks like a great idea. If you add one more color_map following after the
last #break, and add #else before the color_map, it'll be valid for all
times not within the ranges given. That way you get the night sky at 3 a.m.
too, which is one of the times I tried.

Sky coloring is always difficult. Right away I thought the purple didn't
seem correct for the sunrise/sunset. Although, I think if a layer of thin
clouds or water droplets were present in the air this is the color that
might be seen. I'm just guessing, but perhaps a result of the very wide area
it covers it looks out of place. The bright blue above it looks wrong to me
too, too blue without other colors mixed in to offset it. Most times I think
of the real sky colors as muted in some sense, except perhaps the Sun itself
and intensely lit clouds. A bit of imaginative perception can enhance the
coloring. I see a lot of sunrises from my location on a NE facing hillside,
not as many sunsets, and yet I don't believe I could accurately reproduce it
from memory in POV-Ray.

Overall I'd say you have too much red mixed into the blue in those color
maps.

Anyway, I'd suggest the orange range be thinner, closer to the horizon.
Here's my attempt at adjusting all the sky colors. Use them if you wish to,
change them some more, whatever. It's only my interpretation of sky
coloring.

#declare Skycolour = // sunrise
colour_map{
[0 rgb <1,0.1,0.1>]
[0.5125 rgb <1.5,0.2,0.1>]
[0.55 rgb <1,0.8,0.2>]
[0.575 rgb <1,0.6,0.3>]
[0.6 rgb <0.9,0.6,0.6>]
[0.65 rgb <0.25,0.35,0.75>]
[0.725 rgb <0.1,0.2,0.8>]
[1 rgb <0.1,0.1,0.3>]}

#declare Skycolour = // sunset
colour_map{
[0 rgb <1,0.1,0.1>]
[0.5125 rgb <0.9,0.2,0.2>]
[0.55 rgb <0.95,0.75,0.4>]
[0.575 rgb <1,0.6,0.3>]
[0.6 rgb <0.8,0.6,0.5>]
[0.65 rgb <0.2,0.5,0.7>]
[0.725 rgb <0.1,0.4,0.8>]
[1 rgb <0.1,0.2,0.3>]}


#declare Skycolour = // early morning/late afternoon
colour_map{
[0 rgb <1,0,0>]
[0.5 rgb <0.65,0.6,0.9>]
[0.525 rgb <0.35,0.6,0.9>]
[0.6 rgb <0.3,0.55,0.8>]
[0.8 rgb <0.1,0.3,0.9>]
[1 rgb <0.2,0.3,0.7>]}

#declare Skycolour = // midmorning/afternoon
colour_map{
[0 rgb <1,0,0>]
[0.5 rgb <0.6,0.7,0.8>]
[0.525 rgb <0.35,0.55,0.9>]
[0.575 rgb <0.25,0.45,0.8>]
[0.7 rgb <0.2,0.3,1>]
[1 rgb <0.1,0.4,0.7>]}

#declare Skycolour = // noon
colour_map{
[0 rgb <1,0,0>]
[0.5 rgb <0.75,0.75,0.7>]
[0.55 rgb <0.3,0.7,0.9>]
[0.65 rgb <0.15,0.6,0.8>]
[0.8 rgb <0.2,0.4,0.9>]
[1 rgb <0.2,0.3,0.7>]}

#declare Skycolour = // night
colour_map{
[0 rgb <1,0,0>]
[0.5 rgb <0.05,0.075,0.075>]
[0.525 rgb <0.025,0.025,0.1>]
[1 rgb <0,0,0>]}

Oh, and semicolons aren't required for those declares.  :-)  I realize all
you asked for was an opinion but I love to try sky colors myself.

Bob H.

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