POV-Ray : Newsgroups : povray.binaries.images : Not a LOTW Server Time
7 Nov 2024 15:34:01 EST (-0500)
  Not a LOTW (Message 1 to 7 of 7)  
From: Thomas de Groot
Subject: Not a LOTW
Date: 14 Jul 2004 04:27:16
Message: <40f4ee64@news.povray.org>
In the margins of the LOTW projects running here, I try in my own way to
generate interesting landscapes.
I have a question about this isosurface one with a slope/altitude texture.
The bedding plane is vertical. However, I would like to rotate it so that it
shows inclined or even (sub)horizontal bedding. Using rotate doesn't work
(except around the vertical axis). Is that possible?
The relevant code is:

#declare Wrinkling = 1.0; // higher values give sharper features
#declare Wturb = <0.1, 0.5, 0.3>;   // turbulence in wrinkles warp
#declare Wscale = <0.1, 0.1, 0.5>; // wrinkling scale
#declare Wrotate = <0, 0, 0>;   // wrinkling rotation

#declare P1=function {pattern {wrinkles warp {turbulence Wturb octaves 3
omega 0.5 lambda 1} scale Wscale rotate Wrotate}}
#declare P4=function {f_hetero_mf(x,y,z, 0.8, 2, 5, 0, 0.9, 2) }
#declare P=function {  P4(x, 0, z) - P1(x, y, z)*Wrinkling }

isosurface {
  function {y - P(x, 1, 1-z)}
  //open
  max_gradient 10
  contained_by {box {<0.5-Xscale*0.5, -2, 0.5-Zscale*0.5>, <0.5+Xscale*0.5,
1, 0.5+Zscale*0.5>}}
  translate <-0.5, 0, -0.5>
  scale <Loc, 1, Loc>
  pigment {Landtex}
  //translate -Loc/2*x
}


Any help is much appreciated!!!

Thomas


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From: Christoph Hormann
Subject: Re: Not a LOTW
Date: 14 Jul 2004 04:50:01
Message: <cd2s1c$3fe$1@chho.imagico.de>
Thomas de Groot wrote:
> [...]Using rotate doesn't work
> (except around the vertical axis). Is that possible?
> [...]
> 
> isosurface {
>   function {y - P(x, 1, 1-z)}

What did you expect?  The result of P does not depend on the vertical 
coordinate.

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 06 Jul. 2004 _____./\/^>_*_<^\/\.______


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From: Thomas de Groot
Subject: Re: Not a LOTW
Date: 14 Jul 2004 08:51:17
Message: <40f52c45@news.povray.org>
"Christoph Hormann" <chr### [at] gmxde> schreef in bericht
news:cd2s1c$3fe$1@chho.imagico.de...
> Thomas de Groot wrote:
> > [...]Using rotate doesn't work
> > (except around the vertical axis). Is that possible?
> > [...]
> >
> > isosurface {
> >   function {y - P(x, 1, 1-z)}
>
> What did you expect?  The result of P does not depend on the vertical
> coordinate.
>
Hmm... Consider me as a moron where maths is concerned (very far in the
past, and not a dayly meal). So, please take me by the hand and explain what
I should do. After all I used here the function once provided by Mike
Williams, and I do not pretend to understand exactly what it does...

Thomas


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From: Christoph Hormann
Subject: Re: Not a LOTW
Date: 14 Jul 2004 09:15:01
Message: <cd3bdj$66i$1@chho.imagico.de>
Thomas de Groot wrote:
>>>
>>>isosurface {
>>>  function {y - P(x, 1, 1-z)}
>>
>>What did you expect?  The result of P does not depend on the vertical
>>coordinate.
>>
> 
> Hmm... Consider me as a moron where maths is concerned (very far in the
> past, and not a dayly meal). So, please take me by the hand and explain what
> I should do. After all I used here the function once provided by Mike
> Williams, and I do not pretend to understand exactly what it does...

Well, of course you can do this but when you rotate the function around 
the x or z axis and then evaluate the function in the x-z-plane you will 
just rotate the evaluation plane.  But P is still constant in vertical 
direction.  To get a visible effect from a rotation you will need to 
evaluate the function in 3D: function {y - P(x,y,z)} (but you probably 
will need to adapt the function itself to make it look right).

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 06 Jul. 2004 _____./\/^>_*_<^\/\.______


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From: Andrew C on Mozilla
Subject: Re: Not a LOTW
Date: 14 Jul 2004 15:21:18
Message: <40f587ae$1@news.povray.org>
Hey, neat image tho...


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From: Thomas de Groot
Subject: Re: Not a LOTW
Date: 15 Jul 2004 03:18:20
Message: <40f62fbc@news.povray.org>
"Christoph Hormann" <chr### [at] gmxde> schreef in bericht
news:cd3bdj$66i$1@chho.imagico.de...
> Well, of course you can do this but when you rotate the function around
> the x or z axis and then evaluate the function in the x-z-plane you will
> just rotate the evaluation plane.  But P is still constant in vertical
> direction.  To get a visible effect from a rotation you will need to
> evaluate the function in 3D: function {y - P(x,y,z)} (but you probably
> will need to adapt the function itself to make it look right).
>
That makes sense, indeed! <sigh> I think I should dig up those old musty
books, burrowed somewhere in the basement ;-)
Thanks a lot Christoph! You have put me (again) on the right track!

Thomas


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From: Thomas de Groot
Subject: Re: Not a LOTW
Date: 15 Jul 2004 03:20:05
Message: <40f63025@news.povray.org>
"Andrew C on Mozilla" <voi### [at] devnull> schreef in bericht
news:40f587ae$1@news.povray.org...
> Hey, neat image tho...

Thanks Andrew! I liked it a lot too. I probably shall use it somewhere...
Isosurfaces are really addictive!

Thomas


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