Darn, my news reader just crashed as I was writing a reply to this! I'll try and
remember what I said...

Basically it's just a mesh. Each blade is triangular, and is divided in two
along it's length so I can texture it. The texture is uv mapped so that the
blade is opaque at the center of it's base, and fades to transparent at the
edges. This gives a nice soft appearance without the need for hundreds of focal
blur samples :) The blades also vary slightly in colour.

Each blade is placed using the trace() function, by firing a ray vertically down
onto the object. The blade is oriented to point in the direction of the surface
normal, and then the top point is displaced by a vturbulence() function and a
small random displacement.

Here's a couple of bits of source code to help explain that:

//trace a position onto the object
#macro m_Place(vP)
 (trace( oHill, vP+y*5, -y + .3*(<rand(rs),rand(rs),rand(rs)>-.5), vPlaceNorm )
+ vP.y*y)
#end

#declare vPos = 1.3*<rand(rs)*2-1,0,rand(rs)*2-1>;
#declare vPos = m_Place(vPos);

#declare vTop = vPos + vPlaceNorm*.0025;
#declare vTop = vTop + (vturbulence(2, .5, 6, vPos*20)*.0004 +
(<rand(rs),rand(rs),rand(rs)>-.5)*.0004)*<1,.3,1>;

I can post the full source if you like, but I'll probably carry on working on
this image so I'd rather wait until it's "finished".

--
Tek
http://www.evilsuperbrain.com


"Tim Nikias v2.0" <tim### [at] gmxde> wrote in message
news:3eebbd41$1@news.povray.org...
> Would you care to explain a little more in detail how you've
> gone about creating the grass? Placing, object's orientation,
> how many are there, texturing? It looks really great.
>
>
> --
> Tim Nikias v2.0
> Homepage: http://www.digitaltwilight.de/no_lights
> Email: Tim### [at] gmxde
>
> > > Fantastic! Add some flowers, bees or butterflys,
> > > position the camera a little different to make
> > > the fractal more visible, and you've made yourself
> > > a picture worthy of Zazzle!
> >
> > Good ideas, that's the kind of thing this scene needs. Though at the
> moment I'm
> > playing with the lighting instead...
> >
> > I have to admit I didn't think it was that good, but people really seem to
> have
> > picked up on the atmosphere of it so I think I'll develop it further :)
> >
> > --
> > Tek
> > http://www.evilsuperbrain.com
> >
> >
>
>

Post a reply to this message

"Ross Litscher" <lit### [at] osuedu> wrote in message
news:3eebc63e$1@news.povray.org...
> atleast the grass is long.. i'd hate to think someone has to mow this yard
> ;)

Woah, that would be difficult... The only way you could mow that would be to
employ a sheep to graze on the grass, actually a mountain goat would be
better...

> the colors are great too, nice pic!

Thank you :)

--
Tek
http://www.evilsuperbrain.com

Post a reply to this message

Tek <tek### [at] evilsuperbraincom> wrote in message
news:3eebc98c$1@news.povray.org...
> "Ross Litscher" <lit### [at] osuedu> wrote in message
> news:3eebc63e$1@news.povray.org...
> > atleast the grass is long.. i'd hate to think someone has to mow this
yard
> > ;)
>
> Woah, that would be difficult... The only way you could mow that would be
to
> employ a sheep to graze on the grass, actually a mountain goat would be
> better...
>

you now know what you must do. start dropping those goats out of the sky! =)

Post a reply to this message

Thanks!
Hm, so that dividing along the length with the texturing
trick... Do you use just two triangles per blade, or
more? Thats what I couldn't figure out from yer description.

How fast is it? And yet to be answered: how many blades
are in the currect scene?

-- 
Tim Nikias v2.0
Homepage: http://www.digitaltwilight.de/no_lights
Email: Tim### [at] gmxde

> Darn, my news reader just crashed as I was writing a reply to this! I'll
try and
> remember what I said...
>
> Basically it's just a mesh. Each blade is triangular, and is divided in
two
> along it's length so I can texture it. The texture is uv mapped so that
the
> blade is opaque at the center of it's base, and fades to transparent at
the
> edges. This gives a nice soft appearance without the need for hundreds of
focal
> blur samples :) The blades also vary slightly in colour.
>
> Each blade is placed using the trace() function, by firing a ray
vertically down
> onto the object. The blade is oriented to point in the direction of the
surface
> normal, and then the top point is displaced by a vturbulence() function
and a
> small random displacement.
>
> Here's a couple of bits of source code to help explain that:
>
> //trace a position onto the object
> #macro m_Place(vP)
>  (trace( oHill, vP+y*5, -y + .3*(<rand(rs),rand(rs),rand(rs)>-.5),
vPlaceNorm )
> + vP.y*y)
> #end
>
> #declare vPos = 1.3*<rand(rs)*2-1,0,rand(rs)*2-1>;
> #declare vPos = m_Place(vPos);
>
> #declare vTop = vPos + vPlaceNorm*.0025;
> #declare vTop = vTop + (vturbulence(2, .5, 6, vPos*20)*.0004 +
> (<rand(rs),rand(rs),rand(rs)>-.5)*.0004)*<1,.3,1>;
>
> I can post the full source if you like, but I'll probably carry on working
on
> this image so I'd rather wait until it's "finished".
>
> --
> Tek
> http://www.evilsuperbrain.com
>
>
> "Tim Nikias v2.0" <tim### [at] gmxde> wrote in message
> news:3eebbd41$1@news.povray.org...
> > Would you care to explain a little more in detail how you've
> > gone about creating the grass? Placing, object's orientation,
> > how many are there, texturing? It looks really great.
> >
> >
> > --
> > Tim Nikias v2.0
> > Homepage: http://www.digitaltwilight.de/no_lights
> > Email: Tim### [at] gmxde
> >
> > > > Fantastic! Add some flowers, bees or butterflys,
> > > > position the camera a little different to make
> > > > the fractal more visible, and you've made yourself
> > > > a picture worthy of Zazzle!
> > >
> > > Good ideas, that's the kind of thing this scene needs. Though at the
> > moment I'm
> > > playing with the lighting instead...
> > >
> > > I have to admit I didn't think it was that good, but people really
seem to
> > have
> > > picked up on the atmosphere of it so I think I'll develop it further
:)
> > >
> > > --
> > > Tek
> > > http://www.evilsuperbrain.com
> > >
> > >
> >
> >
>
>

Post a reply to this message

On Sat, 14 Jun 2003 22:10:51 +0100
"Tek" <tek### [at] evilsuperbraincom> wrote:

> I like it, it has a nice unreal feeling. What do you think?

  I feel the need to touch it! But it looks more like velvet than grass,
to me (I will like to see it with some nice brown or blue tone).

  Perhaps it would be nice to have the lower part into the water,
letting some foreground space to see the reflections. Anyhow, really
amazing... 


-- 
Jaime Vives Piqueres
		
La Persistencia de la Ignorancia
http://www.ignorancia.org

Post a reply to this message

"Tim Nikias v2.0" <tim### [at] gmxde> wrote in message
news:3eec2c09$1@news.povray.org...
> Hm, so that dividing along the length with the texturing
> trick... Do you use just two triangles per blade, or
> more? Thats what I couldn't figure out from yer description.

Yup 2 triangles per blade. The texture fades from opaque to transparent on the u
axis, and from yellow to green along the v axis. Each blade is mapped with the
same v value on all corners, to pick the colour of the blade, and with the u
value setting how opaque it is.

> How fast is it?

About 2 hours for this image at 1600x1200

> And yet to be answered: how many blades
> are in the currect scene?

250,000!
The bliss image rendered a lot quicker even though there were more blades,
because I created a mesh of 100,000 blades then duplicated it 40 times with
small random displacements. I couldn't do this on this scene because the object
is so complex that it became obvious some of the blades weren't touching it, so
this actually has 1 mesh with 500,000 triangles in it!

--
Tek
http://www.evilsuperbrain.com

Post a reply to this message

"Jaime Vives Piqueres" <jai### [at] ignoranciaorg> wrote in message
news:200### [at] ignoranciaorg...
>   I feel the need to touch it! But it looks more like velvet than grass,
> to me (I will like to see it with some nice brown or blue tone).

Yeah, I was thinking it looked soft, like fur. I may have to render an
alternative version that's covered all over with brown fur :)

>   Perhaps it would be nice to have the lower part into the water,
> letting some foreground space to see the reflections. Anyhow, really
> amazing...

Good suggestion (and very easy to do!) I'll give it a go.

--
Tek
http://www.evilsuperbrain.com

Post a reply to this message

> About 2 hours for this image at 1600x1200

Correction: more like 7 hours! I read the wrong render time.

--
Tek
http://www.evilsuperbrain.com

"Tek" <tek### [at] evilsuperbraincom> wrote in message
news:3eec7463$1@news.povray.org...
> "Tim Nikias v2.0" <tim### [at] gmxde> wrote in message
> news:3eec2c09$1@news.povray.org...
> > Hm, so that dividing along the length with the texturing
> > trick... Do you use just two triangles per blade, or
> > more? Thats what I couldn't figure out from yer description.
>
> Yup 2 triangles per blade. The texture fades from opaque to transparent on the
u
> axis, and from yellow to green along the v axis. Each blade is mapped with the
> same v value on all corners, to pick the colour of the blade, and with the u
> value setting how opaque it is.
>
> > How fast is it?
>
> About 2 hours for this image at 1600x1200
>
> > And yet to be answered: how many blades
> > are in the currect scene?
>
> 250,000!
> The bliss image rendered a lot quicker even though there were more blades,
> because I created a mesh of 100,000 blades then duplicated it 40 times with
> small random displacements. I couldn't do this on this scene because the
object
> is so complex that it became obvious some of the blades weren't touching it,
so
> this actually has 1 mesh with 500,000 triangles in it!
>
> --
> Tek
> http://www.evilsuperbrain.com
>
>

Post a reply to this message

Tek wrote:

> I like it, it has a nice unreal feeling. What do you think?

Very nice !  I like it very much too.

Fabien.

Post a reply to this message

Tek wrote:
> I decided to apply the grass from my "bliss" image to a more interesting object,
> so I made this rather surreal scene.
> 
> The grass looks far better than I thought it would do. Each blade of grass is
> straight, but there's realy nice curves in the overall effect because they lean
> with the shape of the fractal, and also there's a turbulence pattern displacing
> the tops of the blades so you get the feeling the wind is blowing across them.
> Also there's a halo effect round the edge, which has happened completely by
> accident! :)
> 
> I like it, it has a nice unreal feeling. What do you think?

Nice start.. I have some suggestions.

First, tweak your grass-placing code so you don't have grass growing 
straight out sideways. ^^;;

Someone posted a picture a while back that used multilayered grass: a 
smaller, browner layer and a larger green layer. It worked really well. 
It's possible that this image would be better off with just the bright 
green - it adds to the surrealistic look - but you might want to play 
with that and see what happens.

A few flowers or something would look good.. doesn't have to be a lot, 
just enough to add a little variety.

I really like the idea of the chair and umbrella that someone mentioned, 
but I'd leave out the sign and the rowboat; let the furniture speak for 
itself, I think, and if a boat's there then there should also be a 
person there, since the boat didn't row itself, and now your scene's 
just getting messy.. see?

I look forward to more development. This would make great wallpaper. :D

-Xplo

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