Brendan wrote:

> What about the misconception that POV-Ray's objects are solid when they are
> all really surfaces?

They *are* solid, but the texturing is superficial.

--
David Fontaine   <dav### [at] faricynet>   ICQ 55354965
Please visit my website:  http://davidf.faricy.net/

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"Warp" <war### [at] tagpovrayorg> wrote in message
news:39afce77@news.povray.org...
|   The topic says it.
|   If you have some good topic suggestion for this section, please let me
| know.
|
|   And the URL was: http://iki.fi/warp/povVFAQ/

I'll try that again.  Somehow my previous reply lost first use of the word
"moon":

Difficult thing to discern from other things already in the VFAQ.
A misconception could mean beliefs other than POV-specific features.
Such as, is a moon lit on the unseen side?  But then becomes POV-related
when you're wondering if light from a sun object is behind the moon will
illuminate objects behind it via reflected light.  That's already one, sort
of.
Anyway, not easy to think of something.  And I can't think of any very
frequently asked misconceptions at the moment.

Bob

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David Fontaine <dav### [at] faricynet> wrote:
: They *are* solid, but the texturing is superficial.

  Nope. They are only surfaces.
  They are solid when interacting with fog and media, but that's all.

  A simple test: Move the camera inside an object. Is it solid?

  Btw, media is one exception where an "object" is not a surface, but more
or less solid. However, media is seldom considered an object.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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Yes, as someone already noted: Although the misconceptions don't have to
be directly related to povray, it would be good if there was even some
connection and the topic is sometimes seen in povray groups.

  For example, thinking that the positive magnetic pole of the Earth is near
the geographic north pole is a misconception (the positive magnetic pole is
actually near the geographic south pole of the Earth). However, it could
hardly qualify as a logical entry in the VFAQ :)

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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- povray is slow
- a sphere must always look like a circle (same as Ingo)
- water is blue (check last IRTC !!)
- grass is green (rgb <0,1,0>) ...
- a candle flame doesn't cast shadows (when another source is there)

Fabien.

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ingo <ing### [at] homenl> wrote:
: Maybe, "I've put a sun in a corner of my picture, it's oval, not round" 
: and other effect of perspective that are thought of as distortions.

  I added an entry about this.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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Greg M. Johnson <gre### [at] my-dejanewscom> wrote:
: Povray is not a modeller.

  What exactly is the misconception and what should be made clear?

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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Warp wrote:
> 
> Christoph Hormann <Chr### [at] schunteretctu-bsde> wrote:
> : Quite right about the motion blur, but when combining flash with long exposure
> : times in photography, you can achieve an effect similar to the one you
> : criticise.  Of course that's a rare occasion, and would require the main light
> : source being near the camera, but i wanted to mention it.
> 
>   Should I mention this? If yes, could you write a more specific description
> of the phenomenon?

	If the shutter of the camera is open for a relatively long time (say
for instance one second) and that a bright light flashes the scene for a
short interval (i.e about 1/1000 of a second), this will "fix" the moving
objects due to their higher brightness at that time. In photography it is
more common to flash the scene just before closing the shutter to give a
"fixed" object with a dimmed trace behind (for better composition) or to
flash several times to give different snapshots of a moving object on a
single photo (as when studying human walk). There may have others examples
of using this effect, called "slow synchronization" from my french vocabu-
lary ;-)


*** Nicolas Calimet
*** http://pov4grasp.free.fr

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> Quite right about the motion blur, but when combining flash with long exposure
> times in photography, you can achieve an effect similar to the one you
> criticise.  Of course that's a rare occasion, and would require the main light
> source being near the camera, but i wanted to mention it.

	I don't agree that the light source *must* be close to the camera.
Simply this is the most common situation when the internal or added flash
of the camera is used to do this effect.


*** Nicolas Calimet
*** http://pov4grasp.free.fr

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Could you write some hints as what to respond to these (except the
sphere one)?

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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