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"Bob H."
<per### [at] aol com?subject=PoV-News:%20&body=Relating%20to%20POV-Ray:>
wrote in message news:39f613cd$1@news.povray.org...
> "Thomas White" <her### [at] removebtinternet com> wrote in message
> news:39f608de@news.povray.org...
> I see now what you were actually trying to find out about is why a texture
> normal causes the sharp shadow/light boundary on a object. That I don't
know,
> I simply live with the fact. But, I think you are seeing the faked high
parts
> mostly and perhaps the low parts in the normal aren't as obvious, leaving
some
> places with a expected terminator (shadow line) and not other parts. The
> surfaces finish makes a difference in how it appears as well, so if a
highlight
> is on there (esp. with second, third lights) it's all the more
noticeable... or
> unnoticeable. Depends.
> Anyway, it comes down to the same general thing I first said. The faked
high
> spots aren't really higher up than their surroundings and thus only a
> undisturbed shadow line shows up.
> Once again, MegaPOV can do actual surface perturbations so maybe you'll
want to
> try it. Check out isosurface and pigment function (pigment pattern equals
any
> normal pattern of the same type).
Thanks. I've downloaded MegaPov 0.6 and I'm now getting acquainted with it.
Thomas
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Warp wrote:
> Actually, it's not as simple as you state.
>
> The normal modifier DOES indeed affect the shadow line of an object (ie.
> the line that is between the part of the surface that faces the light source
> and the part that faces the opposite direction, ie. the line where the
> shadowed part of the object starts).
> To see how the normal modifier affects this line, try making your object
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.
--
Josh English -- Lexiphanic Lethomaniac
eng### [at] spiritone com
The POV-Ray Cyclopedia http://www.spiritone.com/~english/cyclopedia/
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In article <39F86351.C143C1C2@spiritone.com>, Josh English
<eng### [at] spiritone com> 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] mac com, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tag povray org, http://tag.povray.org/
<><
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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.
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Ron Parker <ron### [at] povray org> 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 -*/
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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] spiritone com> 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] mac com, http://homepage.mac.com/chrishuff/
> TAG: chr### [at] tag povray org, http://tag.povray.org/
>
> <><
--
Josh English -- Lexiphanic Lethomaniac
eng### [at] spiritone com
The POV-Ray Cyclopedia http://www.spiritone.com/~english/cyclopedia/
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"Thomas White" <her### [at] removebtinternet com> 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
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In article <39f9e21b@news.povray.org>, "Thomas White"
<her### [at] removebtinternet com> 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] mac com, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tag povray org, http://tag.povray.org/
<><
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Josh English <eng### [at] spiritone com> 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 -*/
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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] peak edu ee
TAG (Team Assistance Group) e-mail: mar### [at] tag povray org
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