POV-Ray : Newsgroups : povray.general : Patterned Textures and Turbulence : Re: Patterned Textures and Turbulence Server Time
2 Jul 2022 08:20:16 EDT (-0400)
  Re: Patterned Textures and Turbulence  
From: Chris R
Date: 12 May 2022 10:40:00
Message: <web.627d1c0c962984031441ea85cc1b6e@news.povray.org>
"Chris R" <car### [at] comcastnet> wrote:
> "Chris R" <car### [at] comcastnet> wrote:
> > Alain Martel <kua### [at] videotronca> wrote:
> >
> > > > I am working on some scene elements with painted wood, where the paint is
> > > > chipping away, exposing the underlying wood texture.  Since the paint and wood
> > > > have different finishes and normals, I want to use a texture_map rather than
> > > > layered textures.
> > > >
> > > > If I just do scaling/rotation/translation transformations on the texture
> > > > pattern, I know how to compensate for that in the textures in the map so those
> > > > transformations apply to the overall pattern, but not the patterns of the
> > > > individual textures.  However, I can't figure out how to add turbulence to the
> > > > texture pattern without having it affect the textures in the map.
> > > >
> > > > Is this even possible, or do I just need to avoid turbulence in patterned
> > > > textures?
> > > >
> > > > -- Chris R.
> > > >
> > > >
> > > You can apply your turbulence with a negative value :
> > >
> > > warp{turbulence -1} should undo warp{turbulence 1}
> >
> > Ah, thanks.  I should have thought to try that.  I was concerned about how that
> > would affect lambda and omega, but if I understand turbulence correctly, those
> > act more like multipliers on the turbulence value and should thus be negated if
> > turbulence is negative as well.
> >
> > -- Chris R.
>
> So, I tried this and it doesn't seem to work.  The picture below shows an
> example of an object with a gradient x texture_map with leopard and bricks as
> the sub-textures.  The middle picture applies a turbulence just to the gradient
> pattern.  The 3rd picture applies a negative turbulence to each of the
> sub-textures first.
>
>
> -- Chris R.

Just another short observation:

warp { turbulence 1 }
warp { turbulence -1 }

applied to a texture does not result in a non-turbulated texture.  I believe the
issue is that amount of turbulence applied to a point is dependent on the point
itself.  Once you apply the turbulence, and then attempt to apply turbulence
again, you are getting the turbulence from a new point, which will not be the
same as the original point.

-- Chris R.


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