POV-Ray : Newsgroups : povray.newusers : Sharp edges to illumination Server Time
5 Sep 2024 16:17:05 EDT (-0400)
  Sharp edges to illumination (Message 11 to 18 of 18)  
<<< Previous 10 Messages Goto Initial 10 Messages
From: Chris Huff
Subject: Re: Sharp edges to illumination
Date: 26 Oct 2000 16:44:24
Message: <chrishuff-DFF1DF.15472226102000@news.povray.org>
In article <39F86351.C143C1C2@spiritone.com>, Josh English 
<eng### [at] spiritonecom> wrote:

> It's nice that it works, unfortunatly the shadows are also important. 
> What I tried to do was place an identical sphere bounded by the light 
> source to get my shadow back, and it creates the shadowline artifact 
> again... grrr.

Did you make sure the "shadow sphere" was slightly smaller in radius 
than the "real" sphere? If they have the same size and position, 
coincident surfaces can cause a problem.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><


Post a reply to this message

From: Ron Parker
Subject: Re: Sharp edges to illumination
Date: 26 Oct 2000 17:52:18
Message: <slrn8vh9sj.r3f.ron.parker@fwi.com>
On 25 Oct 2000 04:40:19 -0400, Warp wrote:
>  I have suggested some work-arounds for this problem long ago, but no-one
>seems interested enough to make any.

Not true.  The best workaround you proposed still had some problems to be
ironed out, and the conversation died before that could happen.  I did
like the "no-self-shadow" idea though.

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.


Post a reply to this message

From: Warp
Subject: Re: Sharp edges to illumination
Date: 27 Oct 2000 07:01:58
Message: <39f960a6@news.povray.org>
Ron Parker <ron### [at] povrayorg> wrote:
: Not true.  The best workaround you proposed still had some problems to be
: ironed out, and the conversation died before that could happen.

  Sorry :)

:  I did like the "no-self-shadow" idea though.

  Sometimes self-shadowing is essential. This solution works only for
convex objects and for non-convex objects which are positioned so that
they don't cast shadows on themselves.
  However, a coffee cup that doesn't cast a shadow on itself looks quite
unnatural.

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


Post a reply to this message

From: Josh English
Subject: Re: Sharp edges to illumination
Date: 27 Oct 2000 12:54:08
Message: <39F9B32F.AFB55AF0@spiritone.com>
Yup. The second sphere to make the shadow was smaller, but it still created
the artifact on the main one. I even gave it a bland rgb 0 texture with no
normal or finish... nothing really helped.

Josh

Chris Huff wrote:

> In article <39F86351.C143C1C2@spiritone.com>, Josh English
> <eng### [at] spiritonecom> wrote:
>
> > It's nice that it works, unfortunatly the shadows are also important.
> > What I tried to do was place an identical sphere bounded by the light
> > source to get my shadow back, and it creates the shadowline artifact
> > again... grrr.
>
> Did you make sure the "shadow sphere" was slightly smaller in radius
> than the "real" sphere? If they have the same size and position,
> coincident surfaces can cause a problem.
>
> --
> Christopher James Huff
> Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
> TAG: chr### [at] tagpovrayorg, http://tag.povray.org/
>
> <><

--
Josh English -- Lexiphanic Lethomaniac
eng### [at] spiritonecom
The POV-Ray Cyclopedia http://www.spiritone.com/~english/cyclopedia/


Post a reply to this message

From: Thomas White
Subject: Re: Sharp edges to illumination
Date: 27 Oct 2000 16:14:19
Message: <39f9e21b@news.povray.org>
"Thomas White" <her### [at] removebtinternetcom> wrote in message
news:39f7447c@news.povray.org...
> Thanks.  I've downloaded MegaPov 0.6 and I'm now getting acquainted with
it.

Should I be considering MegaPovPlus as well?

Thomas


Post a reply to this message

From: Chris Huff
Subject: Re: Sharp edges to illumination
Date: 27 Oct 2000 16:33:57
Message: <chrishuff-42D9DE.15365627102000@news.povray.org>
In article <39f9e21b@news.povray.org>, "Thomas White" 
<her### [at] removebtinternetcom> wrote:

> Should I be considering MegaPovPlus as well?

MegaPOVPlus is based on an older version of MegaPOV and I haven't 
updated it yet, so unless you want to use particle systems or some of 
the other features, there isn't much reason to get it. MegaPOV is more 
"finished".

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><


Post a reply to this message

From: Warp
Subject: Re: Sharp edges to illumination
Date: 28 Oct 2000 08:21:52
Message: <39fac4e0@news.povray.org>
Josh English <eng### [at] spiritonecom> wrote:
: Yup. The second sphere to make the shadow was smaller, but it still created
: the artifact on the main one. I even gave it a bland rgb 0 texture with no
: normal or finish... nothing really helped.

  There seems to be some misconception here.

  If the inner sphere casts a shadow on the floor, it will certainly cast
a shadow on the (back side of the) outer sphere.
  Pigments (without filters), normals and finishes do not affect shadow
calculations at all. I don't understand why you think that an rgb 0 texture
without finishes and normals would be of any help here.

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


Post a reply to this message

From: Margus Ramst
Subject: Re: Sharp edges to illumination
Date: 29 Oct 2000 15:42:43
Message: <39FC8BBB.7D9E7741@peak.edu.ee>
Josh English wrote:
> 
> Yup. The second sphere to make the shadow was smaller, but it still created
> the artifact on the main one. I even gave it a bland rgb 0 texture with no
> normal or finish... nothing really helped.
> 

This method will work in some limited cases, just remember that the greater the
bump size, the smaller this second object must be in relation to the first.

-- 
Margus Ramst

Personal e-mail: mar### [at] peakeduee
TAG (Team Assistance Group) e-mail: mar### [at] tagpovrayorg


Post a reply to this message

<<< Previous 10 Messages Goto Initial 10 Messages

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.