Being a fairly new pov user I have voraciously toured the many websites
available,
viewing nearly the entire povray-webring and all the sites in the povray
gallery(that
were still good links). In doing so I have had the enjoyment of seeing a
lot of great
stuff. But in my travels(well actually I didn't leave my chair) I
noticed on occasion
that some objects are surrounded by a kind of ...well... "aura" for lack
of a better
description. Most often(or maybe it's just me) this effect seems to
accompany spline
based objects. An example of what I'm talking about can be found at the
Colefax
website. The Spline Generator page has two images; both have this
effect(or maybe
I should say artifact). If you run the animation it's a bit more
obvious.
I am wondering what causes this(mystical enchantment?), and how it can
be avoided
("...don't use splines stupid...").

--
...coffee?...yes please! extra sugar,extra cream...Thank you.

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Phil Clute wrote:
> 
> Being a fairly new pov user I have voraciously toured the many websites
> available,
> viewing nearly the entire povray-webring and all the sites in the povray
> gallery(that
> were still good links). In doing so I have had the enjoyment of seeing a
> lot of great
> stuff. But in my travels(well actually I didn't leave my chair) I
> noticed on occasion
> that some objects are surrounded by a kind of ...well... "aura" for lack
> of a better
> description. Most often(or maybe it's just me) this effect seems to
> accompany spline
> based objects. An example of what I'm talking about can be found at the
> Colefax
> website. The Spline Generator page has two images; both have this
> effect(or maybe
> I should say artifact). If you run the animation it's a bit more
> obvious.
> I am wondering what causes this(mystical enchantment?), and how it can
> be avoided
> ("...don't use splines stupid...").
> 
> --
> ...coffee?...yes please! extra sugar,extra cream...Thank you.

  I think what you are seeing is more related to the jpg artifacts
than any real attribute of using slpines. The Colefax example of
columns had high values of reflection on it that create bright
areas around an object that effect how well jpg compression works.
  The second had a background with a high diffuse value that has
similar problems. You will find these kinds of unwanted traits
happen not only with jpgs but also with animations where the original
24 bit image is compressed and or reduced in color content. There
is not much that can be done abuot it other than plan your scenes
around these limitations. By this I mean don't use areas that abruptly
go from shiny bright to dark on a objects edge. You get the bright
objects saturating the pixels around them and it is more visible when
the surrounding areas are dark.

  Either that or splines got magic. You make the call.

-- 
Ken Tyler

mailto://tylereng@pacbell.net

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Hey, if it's jpg artifacts you wanna see check my two gallery pages
again (or for the first time) since I've reorganized the webspace. I
removed everything and re-made the jpgs using 50% compression (quality)
on every picture thats not a gif or a small background image. Preview
thumbnails too. It may look kind of disturbing however I managed to cut
the space used in half and speed up the load times by a great deal.
Thinking of doing an exclusive png gallery for the best of the bunch,
giving the viewer a choice. Thank me later ;)


Ken wrote:
> 
> Phil Clute wrote:
> >
> > Being a fairly new pov user I have voraciously toured the many websites
> > available,
> > viewing nearly the entire povray-webring and all the sites in the povray
> > gallery(that
> > were still good links). In doing so I have had the enjoyment of seeing a
> > lot of great
> > stuff. But in my travels(well actually I didn't leave my chair) I
> > noticed on occasion
> > that some objects are surrounded by a kind of ...well... "aura" for lack
> > of a better
> > description. Most often(or maybe it's just me) this effect seems to
> > accompany spline
> > based objects. An example of what I'm talking about can be found at the
> > Colefax
> > website. The Spline Generator page has two images; both have this
> > effect(or maybe
> > I should say artifact). If you run the animation it's a bit more
> > obvious.
> > I am wondering what causes this(mystical enchantment?), and how it can
> > be avoided
> > ("...don't use splines stupid...").
> >
> > --
> > ...coffee?...yes please! extra sugar,extra cream...Thank you.
> 
>   I think what you are seeing is more related to the jpg artifacts
> than any real attribute of using slpines. The Colefax example of
> columns had high values of reflection on it that create bright
> areas around an object that effect how well jpg compression works.
>   The second had a background with a high diffuse value that has
> similar problems. You will find these kinds of unwanted traits
> happen not only with jpgs but also with animations where the original
> 24 bit image is compressed and or reduced in color content. There
> is not much that can be done abuot it other than plan your scenes
> around these limitations. By this I mean don't use areas that abruptly
> go from shiny bright to dark on a objects edge. You get the bright
> objects saturating the pixels around them and it is more visible when
> the surrounding areas are dark.
> 
>   Either that or splines got magic. You make the call.
> 
> --
> Ken Tyler
> 
> mailto://tylereng@pacbell.net

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/POVring.htm
 mailto:inv### [at] aolcom?PoV

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Bob Hughes wrote:
>Hey, if it's jpg artifacts you wanna see check my two gallery pages
>again (or for the first time) since I've reorganized the webspace. I
>removed everything and re-made the jpgs using 50% compression (quality)

>on every picture thats not a gif or a small background image. Preview
>thumbnails too. It may look kind of disturbing however I managed to cut

>the space used in half and speed up the load times by a great deal.
>Thinking of doing an exclusive png gallery for the best of the bunch,
>giving the viewer a choice. Thank me later ;)

Yes indeed, that's the stuff.
Your site does download quicker now. And good
work on the pov-map, it's pretty cool.

I can never seem to work those stereo images, I get it for a second and
then lose it. And when I do get it my eyes are too blurry to make
anything out.
Have you ever tried making 3D for the red&blue glasses(or did I just
miss it?)?




--
...coffee?...yes please! extra sugar,extra cream...Thank you.

Post a reply to this message

Red/blue glasses!? No way, they can be interesting novelty pictures but
not suitable for a good, true 3D, look of an image. Afraid the main
problem is to see the stereo pairs comfortably is to be quite a good
distance away from the monitor screen. The further the easier. And then
you see smaller pictures is the problem there. Nothing compares though
to seeing the raw image as it was rendered, other methods of 3D viewing
compromise something about the image, whether it be color or distortion.
Even the stereo pair method causes distortions due to slight changes
between renders of the individual images, most notably the pixelization
variances similar to 'jitter' being used in animations.
I only attempt this stuff, perfection is not available to me.

Phil Clute wrote:
> 
> Bob Hughes wrote:
> >Hey, if it's jpg artifacts you wanna see check my two gallery pages
> >again (or for the first time) since I've reorganized the webspace. I
> >removed everything and re-made the jpgs using 50% compression (quality)
> 
> >on every picture thats not a gif or a small background image. Preview
> >thumbnails too. It may look kind of disturbing however I managed to cut
> 
> >the space used in half and speed up the load times by a great deal.
> >Thinking of doing an exclusive png gallery for the best of the bunch,
> >giving the viewer a choice. Thank me later ;)
> 
> Yes indeed, that's the stuff.
> Your site does download quicker now. And good
> work on the pov-map, it's pretty cool.
> 
> I can never seem to work those stereo images, I get it for a second and
> then lose it. And when I do get it my eyes are too blurry to make
> anything out.
> Have you ever tried making 3D for the red&blue glasses(or did I just
> miss it?)?
> 
> --
> ...coffee?...yes please! extra sugar,extra cream...Thank you.

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/POVring.htm
 mailto:inv### [at] aolcom?PoV

Post a reply to this message