Continuing the discussion I inadvertently started in p.o-t.

Apparently, FlyerX's PoseRay already half-implements the idea that I have
been tossing around in my head for quite some time.  Gilles gave me a couple
other ideas, and I came up with a simple, yet not altogether impressive
test.  Even so, I think it may be a good starting point, or
proof-of-concept.

Here's the picture: http://www.beantoad.com/NewImages/mytest8.jpg  It's Judy
with the "Blondie" dynamic hair, that comes with Poser 5.

PoseRay already creates cylindrical "guide hairs" based on the Poser 5 OBJ
export.  All I did was duplicate each of them 30 times, and add a little x &
y translation randomness to the entire hair object.  That's it.

However, as we guessed, the memory usage was enormous.  For 30 hair
replications, my system peaked at about 1.0GB of memory usage (about 750MB
as a result of POV-Ray).  This took about 30 minutes to render on my AMD
Athlon 1800+ with 512MB.  Don't even attempt this with 256MB.  No radiosity,
focal blur, etc., just 3 light sources imported from Poser.

Things I don't like:
The hair is too coarse.  I think it needs to be thinner.  There are not
enough strands of hair.  Perhaps 100+ hairs would make it look much better.
Using cylinders might work if you have 10GB of RAM, but for those of us that
work in the real world, I don't think it's feasible to use cylinders.  The
cylinders would probably need to be replaced with tiny meshes for this to
work with a reasonable amount of RAM (I think?).  Using some
sphere_sweep-like object would be ideal, but would probably not render in
our lifetimes (I think).  The hair texture could be improved.  I just left
it as PoseRay exported it (grayish-black).  And the under-hair mesh is
causing that strange bright-spot below her neck (oops).

Here's the code, to add to the end of your *_pov.inc PoseRay include file.
If anyone wants to work on this idea some more, feel free.  I think the
initial proof-of-concept went fairly well.

#declare r1=seed(123);
#macro DynamicHair(NumReplications)
  union {
    #local i=0;
    #while (i < NumReplications)
      object { poseraylinegroup
        translate <rand(r1)-0.5,0, rand(r1)-0.5>*0.01
      }
      #local i=i+1;
    #end
  }
#end

#declare MyTest8=union{ object{MyTest8_mesh} object {DynamicHair(30) } }

--
Jeremy

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news:3fd9219d$1@news.povray.org...

> Here's the picture: http://www.beantoad.com/NewImages/mytest8.jpg  It's
Judy
> with the "Blondie" dynamic hair, that comes with Poser 5.

It's really looking good, and better than a lot of the usual
texture/geometry hair. This could lead to something interesting. The main
problems seem to be the memory cost and the overall "corse" aspect which is
due to the lack of visible highlights on small cylinders. Possibly, turning
off the shadow on 50% or more of the hair objects could help with the speed,
I don't know.
A solution could be to have a better object for the hair, with less polys
and more surface, such as a ribbon-like strand with a semi-transparent uv
texture with painted hair (or even procedural, a gradient could do the
trick). With clever instanciation
It's not going to be fast anyway. Antialising on small things + layers of
transparency = bad. It take ages even on regular hair objects with just a
couple of layers. Radiosity just hates them too : layers become black when
quality is raised, a major issue with Poser hair + quality rad (and
max_trace_level doesn't solve it).

G.

-- 

**********************
http://www.oyonale.com
**********************
- Graphic experiments
- POV-Ray and Poser computer images
- Posters

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On Fri, 12 Dec 2003 19:23:22 +0100, "Gilles Tran" <tra### [at] inapginrafr> wrote:

>Radiosity just hates them too : layers become black when
>quality is raised, a major issue with Poser hair + quality rad (and
>max_trace_level doesn't solve it).

That just a guess Gilles? :-}

I suppose you know but I'll mention it in case anyone else doesn't. Poser 4 has
a hair feature. To access it just type HAIR and the treemaker window appears.
You can get a utility called "Fur Fur" from PAE at 
http://www.eurus.dti.ne.jp/~masasi/Service/indexE.html
to make it usable. Having said that I've not made anything I can use but I've
not spent much time on it as you can't animate it :-{
Simple tutorial at 
http://www.eurus.dti.ne.jp/~masasi/PROGRAM/indexE.html


Regards
        Stephen

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news:3qoktv8tjnj132ds8cn89a0pa997r023il@4ax.com...

> I suppose you know but I'll mention it in case anyone else doesn't. Poser
4 has
> a hair feature. To access it just type HAIR and the treemaker window
appears.

Yes, the P4 easter egg... Actually I suspect it to have been an early
version of the P5 hair feature. I haven't done much with it either, mostly
because it wasn't possible to control where the hair grew, within Poser at
least. I spent an hour covering a cow model with it, got a 50 mb mesh and
stopped...

G.


-- 
**********************
http://www.oyonale.com
**********************
- Graphic experiments
- POV-Ray and Poser computer images
- Posters

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On Sat, 13 Dec 2003 02:49:40 +0100, "Gilles Tran" <gitran_nospam_@wanadoo.fr>
wrote:

> I spent an hour covering a cow model with it, got a 50 mb mesh and
>stopped...

Surprise :-}

Regards
        Stephen

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