Hello,

one can see the picture I post on pbi (the post was water texture). This
picture was done with lightwave (not by me :)). So this use shader. If I
have well understood, a shader can give texture (like povray texture)
but also give a 3D deformation of the object (example: a sphere can be
deformed by a shader to look like a AIDS virus (with small cones
everywhere and this is real 3d cones)). So with shader it is sometime
more simple to modelling things (but certainly more complex).

If you look the picture, you will see two scale in the normal:

1) one which look like a large scale bump
2) another which you like a smaller scale pattern (but which one??)

The question is:

how can I make a normal with two scale like this?

I have try with normal_map but without success (it is perhaps because I
am not so good :)). The best result I have obtained is with layered
texture but it is quite hard!!

I thing it could be interesting for povray evolution to find good
textures for common things.

For clouds, many user have found good methods (example: jaime vives
Piqueres http://members.xoom.com/jaimevives/).

But for water, ocean etc... perhaps one can do better.

Suggestion?

Fabian.

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Fabian Brau wrote:
> 
> If you look the picture, you will see two scale in the normal:
> 
> 1) one which look like a large scale bump
> 2) another which you like a smaller scale pattern (but which one??)
> 
> The question is:
> 
> how can I make a normal with two scale like this?
> 
> I have try with normal_map but without success (it is perhaps because I
> am not so good :)). The best result I have obtained is with layered
> texture but it is quite hard!!
> 

Clouds, water ripples, landscapes - they all have one thing in common:
they are fractal by nature. So to approximate them, some kind of fractal
noise tends to be the best method. The granite pattern is fractal noise,
iirc so is wrinkles. You can also create fractal noise by averaging
together several differently-scaled bozo patterns.
I myself like to use the latter, since this gives the most control over
the pattern. I believe you could get something like the example pattern
with this method. It won't be easy, no. But getting good results is
seldom easy.

Margus

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Fabian Brau <fab### [at] umhacbe> wrote:
: how can I make a normal with two scale like this?

: I have try with normal_map but without success (it is perhaps because I
: am not so good :)). The best result I have obtained is with layered
: texture but it is quite hard!!

  Use the normal { average normal_map { ... } }

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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Margus Ramst wrote:
> The granite pattern is fractal noise,

I believe the granite pattern uses 3D perlin noise - I am not sure it
is strictly fractal in nature...

--
Ken "who had been wrong before" Tyler

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IIRC, the manual says granite is 1/f fractal noise. Anyway, perlin noise
_is_ by definition fractal noise, i.e. it has multiple levels of detail.
Bozo is perlin noise, but it has only one octave, so it is not strictly
fractal yet. By adding together several bozo patterns you increase the
octaves of perlin noise, giving it fractal nature.

Margus

Ken wrote:
> 
> I believe the granite pattern uses 3D perlin noise - I am not sure it
> is strictly fractal in nature...
> 
> --
> Ken "who had been wrong before" Tyler

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Nieminen Juha <war### [at] punarastascstutfi> writes:

> Fabian Brau <fab### [at] umhacbe> wrote:
> : how can I make a normal with two scale like this?
> 
> : I have try with normal_map but without success (it is perhaps because I
> : am not so good :)). The best result I have obtained is with layered
> : texture but it is quite hard!!
> 
>   Use the normal { average normal_map { ... } }

In my opinion, a very good normal map for water surfaces is given in:

Steven Worley
A Cellular Texture Basis Function
Computer Graphics Prooceedings
Annual Conference Series, 1996
ACM 0-89791-746-4/96/008

You can find an online overview at:
http://graphics.lcs.mit.edu/~mcm/6.838j/worley/s1.html
Two ocean images are included.

I've played around with it by adding (not averaging) modified crackle
patterns. One or two pictures should still reside in p.b.i with subject
"ocean". The rest of the texture (pigment and finish) were far from
perfect, though.

I hope this helps.
Thomas

-- 
http://thomas.willhalm.de/
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Hello,

An average of granite do a good job! Thanks, but I don't know if it is
the better choice :)! But this is good for me!

Fabian.

Fabian Brau wrote:
> 
> Hello,
> 
> one can see the picture I post on pbi (the post was water texture). This
> picture was done with lightwave (not by me :)). So this use shader. If I
> have well understood, a shader can give texture (like povray texture)
> but also give a 3D deformation of the object (example: a sphere can be
> deformed by a shader to look like a AIDS virus (with small cones
> everywhere and this is real 3d cones)). So with shader it is sometime
> more simple to modelling things (but certainly more complex).
> 
> If you look the picture, you will see two scale in the normal:
> 
> 1) one which look like a large scale bump
> 2) another which you like a smaller scale pattern (but which one??)
> 
> The question is:
> 
> how can I make a normal with two scale like this?
> 
> I have try with normal_map but without success (it is perhaps because I
> am not so good :)). The best result I have obtained is with layered
> texture but it is quite hard!!
> 
> I thing it could be interesting for povray evolution to find good
> textures for common things.
> 
> For clouds, many user have found good methods (example: jaime vives
> Piqueres http://members.xoom.com/jaimevives/).
> 
> But for water, ocean etc... perhaps one can do better.
> 
> Suggestion?
> 
> Fabian.

Post a reply to this message