>>Out of interest... how did you do the birds?
> 
> 
> Knocked them together (very quickly) in sPatch. I knew they were only going
> to be seen from a distance, so they look _really_ terrible close to!

...still better than the triangles I used. :-$

(As in, each "bird" was just a single jet-black triangle.)

But then, I'm rubbish, sadly...

Andrew @ home.

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> Just another landscape...

Oh, your so wrong!  This is not "just another landscape" this is a blummin
loverly poster-like quality to it.  Very Nice.

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On Sat, 08 May 2004 11:23:22 +0100, stephen parkinson
<ste### [at] zmemw16demoncouk> wrote:

>also sun seems oversized ?

If you are referring to technical realism, then not necessarily. The
Sun's apparent size depends on the camera's angular field of view.

FYI, the Sun's angular diameter can be calculated by dividing the
Sun's diameter by the Earth-Sun distance.   This works out, on
average, to 0.00929 radians, or about 0.53 degree.  So with the Sun
modeled accurately, if camera { angle 3 } is used, then the Sun
*would* look as big as in Dave's image.

If you are talking about artistic composition, it's therefore just a
matter of taste, and of what effect Dave wants to achieve.  The size
does seem a bit awkward to me; it looks as if the Sun is too big for
its reflection in the water, or conversly, the reflection is too
narrow for the size of the Sun.  The relative dimness of the Sun
(which is acknowledged) might also be contributing to the sense that
the Sun isn't quite right.

(This is one inaccuracy that shows up in a lot of astronomy paintings.
Up close, a star is too bright to look at--our Sun is an example of
this.  Yet, most artist renderings of stars show all the granulation
and other surface features, which are impossible to see without very
dark or narrowband filters.)

Whatever the size of the Sun however, i think it would have a better
"sunset" feel if it were flattened slightly into an oval, the way
sunsets appear IRL.  (This happens due to refraction through the
atmosphere; the atmosphere is much thicker towards the horizon than
overhead.)

-- 
------------------- Richard Callwood III --------------------
~  U.S. Virgin Islands    ~  USDA zone 11  ~  18.3N, 64.9W  ~
~  eastern Massachusetts  ~  USDA zone 6 (1992-95)          ~
--------------- http://cac.uvi.edu/staff/rc3/ ---------------

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-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Richard Callwood III wrote:
| On Sat, 08 May 2004 11:23:22 +0100, stephen parkinson
| <ste### [at] zmemw16demoncouk> wrote:
|
|
|>also sun seems oversized ?
|
|
| If you are referring to technical realism, then not necessarily. The
| Sun's apparent size depends on the camera's angular field of view.
|
| FYI, the Sun's angular diameter can be calculated by dividing the
| Sun's diameter by the Earth-Sun distance.   This works out, on
| average, to 0.00929 radians, or about 0.53 degree.  So with the Sun
| modeled accurately, if camera { angle 3 } is used, then the Sun
| *would* look as big as in Dave's image.
|
	Remember that we are inside the atmosphere which causes the apparent
size of the sun to change from what it would be viewed from the same
distance in space. In particular, the sun appears bigger when it's
near the horizon, which is the case here...

		Jerome
- --
******************************
*      Jerome M. Berger      *
* mailto:jbe### [at] ifrancecom *
*  http://jeberger.free.fr/  *
******************************
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40a2a958$1@news.povray.org...
> |
> Remember that we are inside the atmosphere which causes the apparent
> size of the sun to change from what it would be viewed from the same
> distance in space. In particular, the sun appears bigger when it's
> near the horizon, which is the case here...
>
> Jerome
> - --
That's half true: light rays bend due to gradient air density and variable
ior but that flattens sun image rather than inflates.
Bigger sun near the horizon is mostly an illusion due to possible comparison
with known references.
Our brain believes that sun is on the  same skysphere as the sky which is
far at the horizon.
As angular size of the sun remains the same, our brain "thinks" it is bigger
Try  (not too long eh?) looking at the sun through a tube when it is low, so
you make abstraction of surrounding and you get rid of this illusion.

Marc

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>40a2a958$1@news.povray.org...
>> Remember that we are inside the atmosphere which causes the apparent
>> size of the sun to change from what it would be viewed from the same
>> distance in space. In particular, the sun appears bigger when it's
>> near the horizon, which is the case here...

On Thu, 13 May 2004 09:25:07 +0200, "Marc Jacquier"
<jac### [at] wanadoofr> wrote:

>That's half true: light rays bend due to gradient air density and variable
>ior but that flattens sun image rather than inflates.

This is why the Sun appears oval at sunset.

>Bigger sun near the horizon is mostly an illusion due to possible comparison
>with known references.
>Our brain believes that sun is on the  same skysphere as the sky which is
>far at the horizon.
>As angular size of the sun remains the same, our brain "thinks" it is bigger

Marc is correct;  it's a psychological illusion, not an optical
effect.  Photographs prove this.  More information is available at:
 http://science.nasa.gov/headlines/y2002/24jun_moonillusion.htm

>Try  (not too long eh?) looking at the sun through a tube when it is low, so
>you make abstraction of surrounding and you get rid of this illusion.

Better with the Moon!  The illusion is the same, but you get to keep
your eyesight.

I've also read that looking at the Moon upside-down will also kill the
effect.  This exercise came with the suggestion that you not try it
where other people can see you. ;-)

-- 
------------------- Richard Callwood III --------------------
~  U.S. Virgin Islands    ~  USDA zone 11  ~  18.3N, 64.9W  ~
~  eastern Massachusetts  ~  USDA zone 6 (1992-95)          ~
--------------- http://cac.uvi.edu/staff/rc3/ ---------------

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