 |
|
|
|
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Hi All!
I have a question to turbulence. As far as I know, should it be
(pseudo-)random. But if you look at a wood texture with turbulence
.15 you will see a "system". There are larger scaled areas oriented
perpendicular to the axises in a regular distance.
to see what I mean render:
plane {z,0
pigment { wood
color_map {[0.0 color red 1][1.0 color rgb 0]}
turbulence .15
}
finish {ambient 1}
}
camera{location z*40 look_at 0}
use (1-cos(pi*clock*2))*.1 instead of .15 in the turbulence statement
for a nice animation.
Now:
is it:
a) a 'feature' of turbulence caused by the fact that turbulence is
*pseudo* random
b) a bug and
b1)is already fixed in megapov/povray3.5
b2)is not fixed yet
b3)is not to fix
c)something else, that is: ________
I whould prefer b1) but I don't think so.
How can I da a workaround?
I just wanted to make a nice simple woodtexture, but those rings
telling me the growth per year show me an unreal 'turbuelence' in the
thickness.
Thanks in advance!
cukk
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On Thu, 19 Apr 2001 18:46:17 +0200, KalleK wrote:
>I have a question to turbulence. As far as I know, should it be
>(pseudo-)random. But if you look at a wood texture with turbulence
>.15 you will see a "system". There are larger scaled areas oriented
>perpendicular to the axises in a regular distance.
It's not really supposed to be pseudo-random. It's supposed to show
high correlation over short distances and near-zero correlation over
longer distances. To accomplish that, it uses a variant of Perlin noise.
If you want more randomness, consider playing with the lambda and omega
parameters to the turbulence. See the documentation for more details.
--
Ron Parker http://www2.fwi.com/~parkerr/traces.html
My opinions. Mine. Not anyone else's.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Working with the 'scene' I realized, that surrounding/covering the
turbulence in a warp-statement changes everything. That's another
strange thing, because no transformations are performed - therefore it
should be the same with or without the warp-statement, shouldn't it?
cukk
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On Fri, 20 Apr 2001 19:17:58 +0200, KalleK wrote:
>Working with the 'scene' I realized, that surrounding/covering the
>turbulence in a warp-statement changes everything. That's another
>strange thing, because no transformations are performed - therefore it
>should be the same with or without the warp-statement, shouldn't it?
Not necessarily. I suggest reading the documentation on the turbulence
warp for enlightenment.
--
Ron Parker http://www2.fwi.com/~parkerr/traces.html
My opinions. Mine. Not anyone else's.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
> Not necessarily. I suggest reading the documentation on the
turbulence
> warp for enlightenment.
Hi Ron!
Well, thank you for the advice...
But, but I'm still not enlighted. May be I struggle with the
language - If I interpret the documentation correctly, with the
turbulence warp you can get the turbulence in the right order in
regard to all other transformations and warps. But in my example there
is no other transformation or warp.
Would you be so kind to quote the part of the turbulencs warp's
documentation I'm not able to find? The fact that there's anything
else but the order that may be changed by that warp.
I don't want to make you or anyone else angry. I just wonder about
pov's behavior - maybe because I read the docs the wrong way. :-(
cukk
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On Sat, 21 Apr 2001 11:26:14 +0200, KalleK wrote:
>> Not necessarily. I suggest reading the documentation on the
>turbulence
>> warp for enlightenment.
>
>Hi Ron!
>Well, thank you for the advice...
>
>But, but I'm still not enlighted.
Perhaps I misunderstood the question, then. Could you post an example
of what you're seeing (in a appropriate newsgroup)?
--
Ron Parker http://www2.fwi.com/~parkerr/traces.html
My opinions. Mine. Not anyone else's.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
> Perhaps I misunderstood the question, then. Could you post an
example
> of what you're seeing (in a appropriate newsgroup)?
>
Ok, I posted a thread to povray.binaries.images:
"turbulences vs. warp{turbulence} (40kbau)"
to explain what my question is.
cukk
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On Mon, 23 Apr 2001 17:06:17 +0200, KalleK wrote:
>
>
>> Perhaps I misunderstood the question, then. Could you post an
>example
>> of what you're seeing (in a appropriate newsgroup)?
>>
>
>Ok, I posted a thread to povray.binaries.images:
>"turbulences vs. warp{turbulence} (40kbau)"
>to explain what my question is.
Ahh, I see it now. Apparently the "wood" pattern does something special
with what we call "classic" turbulence that it does not do with a turbulence
warp. I suspect the idea was to make turbulated wood look more like real
wood by modifying the turbulence function somewhat. Of course, whoever
made that change was not expecting you to look at the end of an entire log
with such a severe colour map.
It's possible that this feature was documented at some point, but the
documentation appears to have disappeared. The idea that turbulence is
special for wood appears to have been in POV-Ray for at least 10 years
now, and this is the first time I've heard of it. I suppose the more
archaeologically minded among us could look at old documentation and
try to divine the purpose of this feature, but it's unlikely that it'll
go away any time soon.
--
Ron Parker http://www2.fwi.com/~parkerr/traces.html
My opinions. Mine. Not anyone else's.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Hi Ron!
Thank you for the explanation!
Now I can sleep well, knowing why POV behaves that way.
cukk
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
