POV-Ray : Newsgroups : povray.advanced-users : World coordinates vs. local coordinates. Server Time
23 Dec 2024 22:44:46 EST (-0500)
  World coordinates vs. local coordinates. (Message 1 to 6 of 6)  
From: Rob Verweij
Subject: World coordinates vs. local coordinates.
Date: 21 Nov 2000 09:43:39
Message: <3A1A89F5.679E641@worldonline.nl>
Hi,

Proffesionally I work with LightWave 3D but when I find some spare time
I love to tinker with good ol' POV-Ray. At this moment I'm recreating
one of the FX I did in LightWave in POV-Ray 3.1g (I also have MegaPOV's
latest version if needed). The scene is all ready and done but now comes
the hard part: the animation.
For the animation to work I need the texture to stay "static" while the
object expands so you get an effect of a moving texture on an object. In
LightWave I'm used to turn on World Coordinates so the texture stays put
and the object can scale up and down without affecting the texture's
scaling. I can't find anything in the POV-Ray docs about World
Coordinates or Local Coordinates. Can anyone point me into the right
direction? It's a very cool effect and if finished I will post it in the
binaries section.

Thanx,

Rob Verweij.


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From: Ron Parker
Subject: Re: World coordinates vs. local coordinates.
Date: 21 Nov 2000 09:47:07
Message: <slrn91l2nd.dji.ron.parker@fwi.com>
On Tue, 21 Nov 2000 15:43:01 +0100, Rob Verweij wrote:
>For the animation to work I need the texture to stay "static" while the
>object expands so you get an effect of a moving texture on an object. In

The usual way to do this is put the transformations before the textures, 
like so:

sphere { 0,1
  scale (clock+1)
  texture {...}
}

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


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From: Christoph Hormann
Subject: Re: World coordinates vs. local coordinates.
Date: 21 Nov 2000 09:52:34
Message: <3A1A8C33.1F05AEB4@schunter.etc.tu-bs.de>
There is no World Coordinates / Local Coordinates difference in povray
(apart from UV mapping but that's something different)

If you don't want a texture to move with an object it's the easiest way to
apply the texture *after* transforming the object.  Example:

object {
  XXX
  translate YYY
  texture { ... }
}

If that's not possible you will have to transform the texture opposite to
the object's transformation.  A declared transform {} might be useful.

Christoph


-- 
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/


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From: Rob Verweij
Subject: Re: World coordinates vs. local coordinates.
Date: 21 Nov 2000 10:01:42
Message: <3A1A8E31.1B41AC09@worldonline.nl>
Never mind found it! I placed the scale modifier before the texture
declaration and it works fine!

Rob.

Rob Verweij schreef:

> Hi,
>
> Proffesionally I work with LightWave 3D but when I find some spare time
> I love to tinker with good ol' POV-Ray. At this moment I'm recreating
> one of the FX I did in LightWave in POV-Ray 3.1g (I also have MegaPOV's
> latest version if needed). The scene is all ready and done but now comes
> the hard part: the animation.
> For the animation to work I need the texture to stay "static" while the
> object expands so you get an effect of a moving texture on an object. In
> LightWave I'm used to turn on World Coordinates so the texture stays put
> and the object can scale up and down without affecting the texture's
> scaling. I can't find anything in the POV-Ray docs about World
> Coordinates or Local Coordinates. Can anyone point me into the right
> direction? It's a very cool effect and if finished I will post it in the
> binaries section.
>
> Thanx,
>
> Rob Verweij.


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From: Chris Huff
Subject: Re: World coordinates vs. local coordinates.
Date: 21 Nov 2000 12:43:13
Message: <chrishuff-7D7BB0.12433521112000@news.povray.org>
In article <3A1A8C33.1F05AEB4@schunter.etc.tu-bs.de>, 
chr### [at] gmxde wrote:

> If that's not possible you will have to transform the texture opposite to
> the object's transformation.  A declared transform {} might be useful.

If you are using MegaPOV, the transform syntax has been modified so you 
can use the "inverse" keyword to get the inverse of a transform, which 
could be very useful for this. However, this is rarely necessary, since 
you can usually do it by putting the transforms before the texture.

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

<><


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From: Christoph Hormann
Subject: Re: World coordinates vs. local coordinates.
Date: 21 Nov 2000 13:46:35
Message: <3A1AC30C.40ADD9D9@schunter.etc.tu-bs.de>
Chris Huff wrote:
> 
> If you are using MegaPOV, the transform syntax has been modified so you
> can use the "inverse" keyword to get the inverse of a transform, which
> could be very useful for this. However, this is rarely necessary, since
> you can usually do it by putting the transforms before the texture.
> 

Sure, i just thought it might be a complicated csg with parts textured
individually, then the inverse transform could be easier in some cases.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/


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