 |
|
|
|
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Alain <aze### [at] qwerty gov> wrote:
> Have you tried the good ol sky_sphere? It's "surface" is set at
> "infinity".
Actually, technically a sky_sphere is a unit sphere (ie. radius 1)
around the camera (well, not really around the camera, but around the
origin of each ray). Not really "infinite". :P
(The reason why it looks like it's farther away than any other
object is that its color is taken only if the ray did not hit anything
else. Thus the color of the sky sphere looks like it's behind every
object.)
--
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}// - Warp -
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Warp nous apporta ses lumieres ainsi en ce 2004-11-04 06:29... :
>Alain <aze### [at] qwertygov> wrote:
>
>
>>Have you tried the good ol sky_sphere? It's "surface" is set at
>>"infinity".
>>
>>
>
> Actually, technically a sky_sphere is a unit sphere (ie. radius 1)
>around the camera (well, not really around the camera, but around the
>origin of each ray). Not really "infinite". :P
> (The reason why it looks like it's farther away than any other
>object is that its color is taken only if the ray did not hit anything
>else. Thus the color of the sky sphere looks like it's behind every
>object.)
>
>
>
Even if it's not realy at infinity, it look like it is.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Warp wrote:
> Alain <aze### [at] qwertygov> wrote:
>
>>Have you tried the good ol sky_sphere? It's "surface" is set at
>>"infinity".
>
>
> Actually, technically a sky_sphere is a unit sphere (ie. radius 1)
> around the camera (well, not really around the camera, but around the
> origin of each ray). Not really "infinite". :P
> (The reason why it looks like it's farther away than any other
> object is that its color is taken only if the ray did not hit anything
> else. Thus the color of the sky sphere looks like it's behind every
> object.)
>
As counter-intuitive ideas go, put that near the top of the list. How
does it work if a reflected ray never hits?
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
> As counter-intuitive ideas go, put that near the top of the list. How
> does it work if a reflected ray never hits?
Then it takes the color of the sky_sphere as though it were centered at the
origin of the reflected ray.
What Warp was saying was merely a distinction about how the ray-sky_sphere
intersection is actually calculated. For practical purposes, it's sufficient
to imagine it as a sphere with infinite radius, but it's always useful to
know exactly what's going on as this can explain some otherwise unintuitive
behaviors (such as the interaction between a sky_sphere and an orthographic
camera).
- Slime
[ http://www.slimeland.com/ ]
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Slime <fak### [at] emailaddress> wrote:
> What Warp was saying was merely a distinction about how the ray-sky_sphere
> intersection is actually calculated. For practical purposes, it's sufficient
> to imagine it as a sphere with infinite radius
It is actually quite important to know that the sky_sphere behaves like
a unit sphere around the origin of the ray.
Why? Because when you apply a pigment to it, it works like a unit sphere.
If you start thinking "hey, sky sphere is infinitely large, how can I
apply a gradient pigment to it? I can't scale it infinitely large!" you
get into problems.
--
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
In article <418afe1a$1@news.povray.org>, "Slime" <fak### [at] emailaddress>
wrote:
> > As counter-intuitive ideas go, put that near the top of the list. How
> > does it work if a reflected ray never hits?
>
> Then it takes the color of the sky_sphere as though it were centered at the
> origin of the reflected ray.
Actually, centered at < 0, 0, 0>, no matter what the origin of the ray.
Otherwise reflections and refractions would look really, really weird.
(Consider an image of smooth water...two nearby points on the water
would see totally different skies. And the sky seen through a window
would be completely different from that seen directly, because the rays
would originate from the glass, not the camera.)
And there's not really any surface, it's just a pigment determining the
background color. That's why you can't use normal, finish, or interior.
(Though you could define the normal as the mirror of the ray direction,
POV-Ray didn't last I checked.)
Basically, it takes the normalized direction of the ray as the pigment
evaluation point.
--
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: <chr### [at] tagpovrayorg>
http://tag.povray.org/
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
> Basically, it takes the normalized direction of the ray as the pigment
> evaluation point.
That's what I was trying to say. I guess I should have clarified that the
texture of the sphere is taken as though it were centered on the origin.
When I said that it was centered at the origin of the ray, I was only
thinking of the intersection calculation.
- Slime
[ http://www.slimeland.com/ ]
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
nomail@nomail news:web.4188466fe9fa4a2034d765680@news.povray.org
Objects smaller then 0.1 unit are begining to have shadow-problems if they
are semi-transparent.
--
http://www.raf256.com/3d/
Rafal Maj 'Raf256', home page - http://www.raf256.com/me/
Computer Graphics
Post a reply to this message
|
|
| |
| |
|
|
From: Thorsten Froehlich
Subject: Re: How much is TOO FAR and TOO BIG?
Date: 12 Nov 2004 17:30:41
Message: <41953991@news.povray.org>
|
|
|
| |
| |
|
|
In article <Xns959FD77BCFDC9raf256com@203.29.75.35>, "Rafal 'Raf256' Maj"
<spa### [at] raf256com> wrote:
> Objects smaller then 0.1 unit are begining to have shadow-problems if they
> are semi-transparent.
That is plain wrong.
Even under the worst conditions objects of size 0.001 will still be rendered
correctly. As will objects of one million units in size and offset. Beyond
that, it depends on many details, but it can in general be assumed that
values beyond 10e10 and 10e-10 respectively will never produce correct
results.
Thorsten
____________________________________________________
Thorsten Froehlich
e-mail: mac### [at] povrayorg
I am a member of the POV-Ray Team.
Visit POV-Ray on the web: http://mac.povray.org
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
tho### [at] trfde news:41953991@news.povray.org
> Even under the worst conditions objects of size 0.001 will still be
> rendered correctly. As will objects of one million units in size and
> offset. Beyond that, it depends on many details, but it can in
> general be assumed that values beyond 10e10 and 10e-10 respectively
> will never produce correct results.
>
I have scene that had problems on 3.6, I will try to post minimal source to
reproduce that problem.
--
http://www.raf256.com/3d/
Rafal Maj 'Raf256', home page - http://www.raf256.com/me/
Computer Graphics
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
