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I have made an isosurface and there is a lot of banding on it, as you
can see in the image below. Any tips on eliminating it, asides from
simply reducing the accuracy a few orders of magnitude?
#declare celly=function{pigment{cells}}
#declare fnoise=16;//40;
isosurface{
function{y/160-
celly((x+1000)/fnoise,y/fnoise,(z+1000)/fnoise)
}
accuracy 0.01
threshold 0.0 // .03
contained_by {sphere{0,600}
pigment{SeaGreen} normal{bumps}
finish{ambient 0.2}
}
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Attachments:
Download 'cells.jpg' (48 KB)
Preview of image 'cells.jpg'
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Well, I tried a much higher accuracy and got many lines to go away with a
surprisingly small increase in render time. The next question is, why are the
sides so dark?
"Greg M. Johnson" wrote:
> I have made an isosurface and there is a lot of banding on it, as you
> can see in the image below. Any tips on eliminating it, asides from
> simply reducing the accuracy a few orders of magnitude?
>
> #declare celly=function{pigment{cells}}
> #declare fnoise=16;//40;
>
> isosurface{
> function{y/160-
> celly((x+1000)/fnoise,y/fnoise,(z+1000)/fnoise)
> }
> accuracy 0.01
> threshold 0.0 // .03
> contained_by {sphere{0,600}
> pigment{SeaGreen} normal{bumps}
> finish{ambient 0.2}
> }
>
> ------------------------------------------------------------------------
> [Image]
Post a reply to this message
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From: Greg M Johnson
Subject: diffuse ==0 on edges of step functions in isosurfaces
Date: 16 Sep 2000 22:13:02
Message: <39c428ae@news.povray.org>
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I think I've stumbled onto a more serious problem. Looks like megapov insists
on acting as if edges of step functions have zero diffuse.
Will continue in p.u.p.
"Greg M. Johnson" wrote:
> I have made an isosurface and there is a lot of banding on it, as you
> can see in the image below. Any tips on eliminating it, asides from
> simply reducing the accuracy a few orders of magnitude?
>
> #declare celly=function{pigment{cells}}
> #declare fnoise=16;//40;
>
> isosurface{
> function{y/160-
> celly((x+1000)/fnoise,y/fnoise,(z+1000)/fnoise)
> }
> accuracy 0.01
> threshold 0.0 // .03
> contained_by {sphere{0,600}
> pigment{SeaGreen} normal{bumps}
> finish{ambient 0.2}
> }
>
> ------------------------------------------------------------------------
> [Image]
Post a reply to this message
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In article <39c3f5ca@news.povray.org>, "Greg M. Johnson"
<"gregj;-)56590\""@aol.c;-)om> wrote:
> I have made an isosurface and there is a lot of banding on it, as you
> can see in the image below. Any tips on eliminating it, asides from
> simply reducing the accuracy a few orders of magnitude?
Well, they most likely come from the fact that the pattern you are using
has sudden changes, it is non-continuous. The isosurface solver has
trouble solving this type of function. I don't think there is a good way
to fix it in this case, I would just use a bunch of boxes. In other
cases, you could try to smooth the pattern, or maybe output an image and
use an image_mapped pigment function with interpolation.
--
Christopher James Huff
Personal: chr### [at] mac com, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/
<><
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Thanks, I was hoping for a procedural city, infinite in size, which would
enable me to have it buzzing with ships dodging the buildings, etc.
Chris Huff wrote:
> In article <39c3f5ca@news.povray.org>, "Greg M. Johnson"
> <"gregj;-)56590\""@aol.c;-)om> wrote:
>
> > I have made an isosurface and there is a lot of banding on it, as you
> > can see in the image below. Any tips on eliminating it, asides from
> > simply reducing the accuracy a few orders of magnitude?
>
> Well, they most likely come from the fact that the pattern you are using
> has sudden changes, it is non-continuous. The isosurface solver has
> trouble solving this type of function. I don't think there is a good way
> to fix it in this case, I would just use a bunch of boxes. In other
> cases, you could try to smooth the pattern, or maybe output an image and
> use an image_mapped pigment function with interpolation.
>
> --
> 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
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In article <39c42a63@news.povray.org>, "Greg M. Johnson"
<"gregj;-)56590\""@aol.c;-)om> wrote:
> Thanks, I was hoping for a procedural city, infinite in size, which would
> enable me to have it buzzing with ships dodging the buildings, etc.
You could do something like that with using the noise3d() function to
determine the height of the buildings, and generating buildings as
needed.
--
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/
<><
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As I showed before, the depth image patch worked perfectly for this surface,
but I cannot get a diffuse reflection off the side. Isn't this odd?
Chris Huff wrote:
> In article <39c42a63@news.povray.org>, "Greg M. Johnson"
> <"gregj;-)56590\""@aol.c;-)om> wrote:
>
> > Thanks, I was hoping for a procedural city, infinite in size, which would
> > enable me to have it buzzing with ships dodging the buildings, etc.
>
> You could do something like that with using the noise3d() function to
> determine the height of the buildings, and generating buildings as
> needed.
>
> --
> 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
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In article <39c42c31@news.povray.org>, "Greg M. Johnson"
<"gregj;-)56590\""@aol.c;-)om> wrote:
> As I showed before, the depth image patch worked perfectly for this
> surface, but I cannot get a diffuse reflection off the side. Isn't
> this odd?
No. What do you think is odd about it? If the problem is mainly in the
normal calculation, the depth patch would be completely unaffected. If
an image from the depth patch were used as input, antialiasing and
interpolation could smooth things down enough for normal calculation to
be done.
--
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/
<><
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On Sat, 16 Sep 2000 17:43:10 -0400, Greg M. Johnson wrote:
>
>I have made an isosurface and there is a lot of banding on it, as you
>can see in the image below. Any tips on eliminating it, asides from
>simply reducing the accuracy a few orders of magnitude?
The view seen by one of our pilots as he runs a mission over
Bagdad at 1:30 am local time.
--
Cheers
Steve email mailto:ste### [at] zeroppsuklinuxnet
%HAV-A-NICEDAY Error not enough coffee 0 pps.
web http://www.zeropps.uklinux.net/
or http://start.at/zero-pps
4:03pm up 26 days, 20:16, 2 users, load average: 1.22, 1.09, 1.03
Post a reply to this message
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Greg wrote:
>Thanks, I was hoping for a procedural city, infinite in size, which would
>enable me to have it buzzing with ships dodging the buildings, etc.
Make a mesh object and repeat it? You can get enough copies
of a mesh (without blowing the memory) so that it looks infinite
(gets right up to the horizon).
I just tried the mesh idea and have attached the resultant
image to this post.
Pete
Post a reply to this message
Attachments:
Download 'cells_02.gif' (9 KB)
Preview of image 'cells_02.gif'
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