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I prefer the second image. It appears the blades have a more random length, and the
third appears to have forced curvature and seems
unnatural.
Grim
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I would agree with Hugo.
Of the three, I liked #2 best.
I don't have a problem with the curvature of the grass in #'s 1 and 3, but I would
expect that larger regions of the field would have a more similar direction of the
curvature.
I'm not sure I'm being clear. Maybe this is better:
A large region (like a few square meters) should have most of the grass bending the
same general direction. A neighboring region could have most of the grass bending a
different direction, with a gradual shift in direction between the different regions.
Keep some randomness, of course, but less (or maybe a wider) turbulence.
The grass could even be laying down flat (from wind or rain) but it would mostly be
lying in the same general direction.
On a completely different note:
I thought that your technique was basically just "coloring" the ground to make it
look like grass. But then I saw on the horizon of the nearby knoll (on the left)
that the grass appears to rise above the surface. I'm just itching to have a look at
your technique.
--
Thomas Bates
"Hugo" <hua### [at] post3 teledk> wrote in message news:3ca5cdd0$1@news.povray.org...
> Nr 2 is best.. Less waves and more stiff.. Both textures are best at a
> distance - not surprising - but really good, at a distance! The straight
> ones are *not* too straight IMO.. Besides I wonder if not most blades should
> wave almost in the same direction - either due to wind or the sun, that
> attracts them.
>
> Regards,
> Hugo
>
>
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Rune wrote:
>
> In which of these two images does the grass look more real?
>
> ...and why?
I prefer the second one.. not so wavy, and it seems to blend better in
the distance.
-Xplo
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Rune wrote:
>
> In which of these two images does the grass look more real?
>
> 1: http://rsj.mobilixnet.dk/3d/include/fgrass.jpg
>
> 2: http://rsj.mobilixnet.dk/3d/include/fgrass2.jpg
>
> ...and why? ...and what can be improved?
1. Looking strictly at the grass, it's hard to say, but the flowers in
2 look like they're just floating, and I think 1 has a much nicer blend
into the path.
--
David Fontaine <dav### [at] faricynet> ICQ 55354965
My raytracing gallery: http://davidf.faricy.net/
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Don't like 1, blades are too bent or seem to have too many curves.
No opinion about 3 but can't explain why :-/
Like 2 best, I've seen better, but I would be happy with that.
Alf
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I like grass2 best too. Some reference images from corbis.com:
http://www.luxlab.com/ref/grass/
Maybe you could add fake shading.
_____________
Kari Kivisalo
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"Kari Kivisalo" wrote:
> I like grass2 best too. Some reference images from corbis.com:
> http://www.luxlab.com/ref/grass/
Very good reference images. Thanks!
Looks like grass has a much more crisp green color than I remembered. Unless
the photos have been saturated artificially that is, but I don't think so...
> Maybe you could add fake shading.
I don't think that works with the method I use...
Rune
--
3D images and anims, include files, tutorials and more:
Rune's World: http://rsj.mobilixnet.dk (updated Feb 16)
POV-Ray Users: http://rsj.mobilixnet.dk/povrayusers/
POV-Ray Ring: http://webring.povray.co.uk
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An excellent job. I'm voting for Number 2 so far. It looks the way a
recently-seeded lawn looks as it starts to sprout in the spring.
A quick look at the Corbis reference images reminded me of just how
surprisingly green grass actually is, especially early in the year. It
doesn't seem to bend in any single direction unless the wind is very
strong. In scale it can be rather more thin than memory would have it,
and there's usually a great variation in blade height in any unmown
grass. Long grass can be branchier and more tuft-like than one would
think. In the Midwest US where I live, I've noticed that wild fields of
grass (up close) have much variety of texture and species, lots of
little sticks and brush and weeds sticking up, etc-- clutter, in other
words. All on top of mats of dried matter from previous seasons: the
dirt almost never shows through in a wild field.
I'm sure you've run up against the biggest issue in creating CG grass:
creating
enough bejillions of blades to approximate nature. Limitations of memory
and processing time tend to see to it that the blades must be much
sparser than in a real field, which is so jammed with life that even
from a short distance the grass looks like fuzz. I've often thought that
individual blades may be best for the parts of the scene that are in the
foreground and middle-near, while some other method (one or more layers
of variagated procedural texture?) be used for the background. Sometimes
height-dependent background textures seem tempting, as color and
lushness often vary with moisture levels.
All in all: nice stuff.
DZ
Rune wrote:
> In which of these two images does the grass look more real?
>
> 1: http://rsj.mobilixnet.dk/3d/include/fgrass.jpg
>
> 2: http://rsj.mobilixnet.dk/3d/include/fgrass2.jpg
>
> ...and why? ...and what can be improved?
>
> Thanks in advance,
>
> Rune
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"DZ" wrote:
> An excellent job.
Thanks!
> A quick look at the Corbis reference images reminded
> me of just how surprisingly green grass actually is
Same here. In my newer message "Some grass" which you'll find below, I've
tried making the grass a bit more saturated. Still not quite as green as in
the photos though, because that just didn't look right in this image.
> I'm sure you've run up against the biggest issue in
> creating CG grass: creating enough bejillions of
> blades to approximate nature.
Nope.
> Limitations of memory and processing time tend to
> see to it that the blades must be much sparser than
> in a real field
But the whole concept of my grass is that it's a texture, not individual
blades of grass. So I have only two objects in the scene: two copies of the
same height_field, one translated sligtly above the other.
With my method memory and processing time is absolutely no problem, no
matter how big the field of grass is. :)
Rune
--
3D images and anims, include files, tutorials and more:
Rune's World: http://rsj.mobilixnet.dk (updated Mar 19)
POV-Ray Users: http://rsj.mobilixnet.dk/povrayusers/
POV-Ray Ring: http://webring.povray.co.uk
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Wow, that's cool! But how can suprimposed heightfields create the blade-like
shapes?
DZ
Rune wrote:
> > "DZ" wrote:
>
> > I'm sure you've run up against the biggest issue in
> > creating CG grass: creating enough bejillions of
> > blades to approximate nature.
>
> Nope. [...] the whole concept of my grass is that it's a texture, not
> individual
> blades of grass. So I have only two objects in the scene: two copies of the
> same height_field, one translated sligtly above the other.
>
> With my method memory and processing time is absolutely no problem, no
> matter how big the field of grass is. :)
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