Hi Warp!

>   I made this simple tutorial. 

Excellent! I had such a thing in mind for a long time, but you've beaten
me to it -- and to be honest, you've done a better job than I could've
ever done :)


Regards,
Florian

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"Warp" <war### [at] tagpovrayorg> wrote in message 
news:45752fd1@news.povray.org...
>  I made this simple tutorial. Perhaps it may be useful to someone:


I have to add my voice here, too, Warp.  Nicely done.  Simple techniques 
that don't get used often enough.

- How

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I will add my praise to all of the others.  Very well written, simple tricks
for enhancing the image (great job on the wooden floor texture, BTW).  The
sort of thing that I would have written, had I written it :)

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Dan Farmer <dmf### [at] msncom> wrote:
> I will add my praise to all of the others.  Very well written, simple tricks
> for enhancing the image

  Thanks. Getting praise from a celebrity is very flattering.

> (great job on the wooden floor texture, BTW)

  That type of wood texture is actually one of my best developed "tricks"
with POV-Ray's procedural textures I have developed over the years. The
idea is quite simple, yet effective:

- Create a wood-patterned pigment with at least 2 colors (as seen in the
  image, 2 colors is actually often enough, even though using a more
  elaborated color map can increase the visual quality of the texture).
- Apply some turbulence to it.
- Scale it unevenly so that it's very stretched on one direction.

  All the above are actually not my ideas. They have been blatantly copied
from the wood textures included with POV-Ray itself. However, the following
is more original (I'm probably not the *first* person to invent it, but it's
something I didn't see anywhere but developed myself):

- Crate a wood-patterned normal and smooth it out with a slope map.
- Apply the same turbulence and transformations as the pigment so that the
  normal matches perfectly the pigment.
- If you want to create wooden planks, average the above normal definition
  with a gradient-patterned normal which uses a proper slope map.

  Add a nice finish, and that's it: A stunning wooden texture. Simple but
effective.

-- 
                                                          - Warp

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Warp <war### [at] tagpovrayorg> wrote:
>   Thanks. Getting praise from a celebrity is very flattering.

  Hmm, looking at the definition of "flattering" at webster.com (like
"to praise excessively especially from motives of self-interest"), it
might not actually mean what I wanted.

  What I wanted to say was, of course, that it's a great honor.

-- 
                                                          - Warp

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>   I think people too often dismiss normal perturbation tricks because they
> can't get them look good, and the reason is that they don't know how to
> use slope maps.

I have put much time into trying slope maps, and I just can't get them to
look right. I fully understand the idea, but specifying both the height and
the slope at a certain point takes too much tweaking. For instance, I'll
often start with a low point that has a high slope and then put a higher
point with a lower slope. In my head, I imagine a steep surface turning into
a more gradual one. What I end up getting is a steep line, followed by a
slight downward incline, going back up into a gradual slope. This is because
I made the first slope too steep and the second point too low.

I feel like it would be easier to either specify only the slope or only the
height at each point, and rely on some sort of simple smoothing (like a
spline) to get good values inbetween. Or else some sort of editor would be
useful.

So instead, I generally just use functions to create greyscale "height maps"
that I use as normals.

 - Slime
 [ http://www.slimeland.com/ ]

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Thanks, Warp!

That actually helps a lot.  A simply-worded tutorial with spectacular
results like that would be nice to see in the documentation of future
POV-Ray releases.

-Randall

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Warp <war### [at] tagpovrayorg> wrote:
>   That type of wood texture is actually one of my best developed "tricks"
> with POV-Ray's procedural textures I have developed over the years. The
> idea is quite simple, yet effective:

What i found most stunning is the fact that it looks just as good as yours
from the Povray Fractal Contest, which is an isosurface actually!
http://local.wasp.uwa.edu.au/~pbourke/rendering/povfrac/final/0007.html

> - Apply the same turbulence and transformations as the pigment so that the
>   normal matches perfectly the pigment.

yes, matching pigments and normals are something i do frequently.   In fact,
rather than employing manual copy-and-paste, i find myself putting the same
definitions in a macro (function works too!) and calling it in the pigment
or normal, say:

#macro woddy() wood turbulence .1 scale 5*y rotate 5 warp { repeat x*2
offset 2 } #end

pigment { woody() color_map { cm1 } }
normal { woody() slope_map { sm1 } }

> - If you want to create wooden planks, average the above normal definition
>   with a gradient-patterned normal which uses a proper slope map.

hah!  It is indeed a good way to create tiny wooden nods and bumps in the
larger wood texture. :)

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Randall Sawyer <sra### [at] yahoocom> wrote:
> That actually helps a lot.  A simply-worded tutorial with spectacular
> results like that would be nice to see in the documentation of future
> POV-Ray releases.

  The problem I see is that this is a tutorial on scene design, not on
using POV-Ray per se. In other words, it's a tutorial on how to compose
a scene which looks cool, and the tricks can be used on any renderer,
not just POV-Ray.
  The tutorials in the POV-Ray documentation are (and IMO should be)
about how to use POV-Ray itself and its features. Scene composition
is largely irrelevant in that context.

-- 
                                                          - Warp

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>  The problem I see is that this is a tutorial on scene design, not on
> using POV-Ray per se. In other words, it's a tutorial on how to compose
> a scene which looks cool, and the tricks can be used on any renderer,
> not just POV-Ray.

Not fully. Due to the POV scene files included
it's very strongly POV related.

Then you might also delete sections of the POV
help about eg radiosity. I'd like to see such things
in teh POV documentation and there are already
similar tutorials in it.

Just my 2 cents.

Bye, Olaf.

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