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When making wood textures I always run into the same problem. The wood
pattern is too regular. Turbulence seems to make it irregular but not in
the way real wood is. There are a few problems with the current wood:
The constant size of the year rings. On a real tree they vary in size.
The summer part of a ring is wider than the winter part and each ring
(summer+winter) also varies from year to year.
A tree is not round. Depending on the circumstances it grows in, it gets
it shape. If the wind is blowing always from one side, the tree will grow
extra wood on the opposite side. The shape will be more triangular or has
three or more lobes. Also a tree can be "getordeerd" (don't know the
English word, it is as if you fix the roots at their position and rotate
the crown of the tree a few times around z-axis).
Is there a way to create a better pattern with an isosurface? an
somebody point me in the right direction, I lack the math ablility to
figure out something that works.
Ingo
--
Photography: http://members.home.nl/ingoogni/
Pov-Ray : http://members.home.nl/seed7/
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have you already tried black hole warps? i haven't used much wood, but
i know people have used warps to do things like knot holes.
ingo wrote:
>
> When making wood textures I always run into the same problem. The wood
> pattern is too regular. Turbulence seems to make it irregular but not in
> the way real wood is. There are a few problems with the current wood:
> The constant size of the year rings. On a real tree they vary in size.
> The summer part of a ring is wider than the winter part and each ring
> (summer+winter) also varies from year to year.
> A tree is not round. Depending on the circumstances it grows in, it gets
> it shape. If the wind is blowing always from one side, the tree will grow
> extra wood on the opposite side. The shape will be more triangular or has
> three or more lobes. Also a tree can be "getordeerd" (don't know the
> English word, it is as if you fix the roots at their position and rotate
> the crown of the tree a few times around z-axis).
> Is there a way to create a better pattern with an isosurface? an
> somebody point me in the right direction, I lack the math ablility to
> figure out something that works.
>
> Ingo
>
> --
> Photography: http://members.home.nl/ingoogni/
> Pov-Ray : http://members.home.nl/seed7/
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Wasn't it ingo who wrote:
> When making wood textures I always run into the same problem. The wood
>pattern is too regular. Turbulence seems to make it irregular but not in
>the way real wood is. There are a few problems with the current wood:
> The constant size of the year rings. On a real tree they vary in size.
>The summer part of a ring is wider than the winter part and each ring
>(summer+winter) also varies from year to year.
> A tree is not round. Depending on the circumstances it grows in, it gets
>it shape. If the wind is blowing always from one side, the tree will grow
>extra wood on the opposite side. The shape will be more triangular or has
>three or more lobes. Also a tree can be "getordeerd" (don't know the
>English word, it is as if you fix the roots at their position and rotate
>the crown of the tree a few times around z-axis).
> Is there a way to create a better pattern with an isosurface? an
>somebody point me in the right direction, I lack the math ablility to
>figure out something that works.
Here's something that might get you started. The conventional wood
pigment is equivalent to "function {sqrt(x^2 + y^2)}", and I've
substituted "x + F1*0.1" for "x" and "y + F2*0.2" for "y", where F1 and
F2 are pigment functions. By manipulating the pigment functions you
should be able to achieve fine control over several of the features you
require.
The "scale <1.5,1.5,10>" causes the distortion to change more slowly in
the z direction than in the x and y directions.
I've used a color_map in F2, but not F1, because the bozo pigment has a
default color_map that is discontinuous, which would cause
discontinuities in the growth rings.
The fact that the summer part of the growth ring is wider than the
winter part is achieved by arranging for the second color_map to change
colours at 0.2 instead of 0.5. This could be done with a conventional
wood pigment, and doesn't rely on the fact that we're using isosurfaces.
#declare F1=function{pigment{
crackle
scale <1.5,1.5,10>
}
}
#declare F2=function{pigment{
bozo
color_map { [0 rgb 1] [1 rgb 0] }
scale <1.5,1.5,10>
}
}
box {-1,1
pigment { function { sqrt((x+F1*0.3)^2+(y+F2*0.2)^2)*10
}
color_map { [0.0 rgb <.8,.7,0>]
[0.2 rgb <.8,.7,0>]
[0.2 rgb <.7,.5,0>]
[1.0 rgb <.7,.5,0>]
}
}
}
--
Mike Williams
Gentleman of Leisure
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Mike Williams wrote:
>Here's something that might get you started. The conventional wood
>pigment is equivalent to "function {sqrt(x^2 + y^2)}", and I've
>substituted "x + F1*0.1" for "x" and "y + F2*0.2" for "y", where F1 and
>F2 are pigment functions. By manipulating the pigment functions you
>should be able to achieve fine control over several of the features you
>require.
Thank you Mike, this looks like the startingpoint I needed.
Ingo
--
Photography: http://members.home.nl/ingoogni/
Pov-Ray : http://members.home.nl/seed7/
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ryan constantine wrote:
>have you already tried black hole warps?
Yes, with these the right finishing toutch can be added.
Ingo
--
Photography: http://members.home.nl/ingoogni/
Pov-Ray : http://members.home.nl/seed7/
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Slope maps can create great wood textures. Warp posted an excelent example
some time ago.
Mick
I hope he won't mind if I republish it here
box{-3,3
texture
{ pigment
{ wood color_map
{ [0 rgb <.9,.5,.2>]
[1 rgb <.7,.4,.1>]
}
turbulence .5 file://was .3
scale <.3,1,1>
}
normal
{ average normal_map
{ [1 wood .2 slope_map
{ [0 <0,0>]
[.2 <0,0>]
[.3 <.5,1>]
[.5 <1,0>]
[.7 <.5,-1>]
[.8 <0,0>]
[1 <0,0>]
}
turbulence .1 file://was 0
scale <.3,1,1>
]
[1 gradient x 2 slope_map
{ [0 <0,2>]
[.05 <1,0>]
[.95 <1,0>]
[1 <0,-2>]
}
turbulence.025
]
}
}
finish { specular .3 reflection .1 }
}
rotate<45,15,0>
}
"ingo" <ing### [at] home nl> wrote in message
news:8F7378CEseed7@204.213.191.228...
> When making wood textures I always run into the same problem. The wood
> pattern is too regular. Turbulence seems to make it irregular but not in
> the way real wood is. There are a few problems with the current wood:
> The constant size of the year rings. On a real tree they vary in size.
> The summer part of a ring is wider than the winter part and each ring
> (summer+winter) also varies from year to year.
> A tree is not round. Depending on the circumstances it grows in, it gets
> it shape. If the wind is blowing always from one side, the tree will grow
> extra wood on the opposite side. The shape will be more triangular or has
> three or more lobes. Also a tree can be "getordeerd" (don't know the
> English word, it is as if you fix the roots at their position and rotate
> the crown of the tree a few times around z-axis).
> Is there a way to create a better pattern with an isosurface? an
> somebody point me in the right direction, I lack the math ablility to
> figure out something that works.
>
> Ingo
>
> --
> Photography: http://members.home.nl/ingoogni/
> Pov-Ray : http://members.home.nl/seed7/
Post a reply to this message
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