POV-Ray : Newsgroups : povray.binaries.images : Comparing mesh grass with faked grass (32+20 kbu) Server Time
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  Comparing mesh grass with faked grass (32+20 kbu) (Message 11 to 18 of 18)  
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From: Tony[B]
Subject: Re: Comparing mesh grass with faked grass (32+20 kbu)
Date: 3 Apr 2002 13:25:57
Message: <3cab4935@news.povray.org>
The mesh grass looks much thicker than the texture grass. There's also less
variation of color in the above image. It's interesting how they both look
bare in the same spots.


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From: Hugo
Subject: Re: Comparing mesh grass with faked grass (32+20 kbu)
Date: 3 Apr 2002 14:44:39
Message: <3cab5ba7$1@news.povray.org>
It's interesting to compare these two images. I like the grass texture best,
and 15 MB counts for me in any case. But I assume you used a single, strong
lightsource for the mesh grass, which is why the shadows really show up.
This is the biggest difference in the two images. For a more natural
appearance of the mesh, the shadows need to be much more subtle. This will
increase render time. But I assume multiple lightsources or radiosity won't
change the look a lot of your grass texture ... so all in all, there's a
decision to make for every scene.

Oh and I should say "great work!" once again because I'm surprised this is
possible with a texture - even for animation!

Regards,
Hugo


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From: Rune
Subject: Re: Comparing mesh grass with faked grass (32+20 kbu)
Date: 3 Apr 2002 14:59:16
Message: <3cab5f14@news.povray.org>
"Tony[B]" wrote:
> The mesh grass looks much thicker than the texture grass.

That's probably right.

> There's also less variation of color in the above image.

Err, which one of them?

> It's interesting how they both look bare in the same spots.

Glad you find my density maps interesting!

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/
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From: Rune
Subject: UPDATE
Date: 3 Apr 2002 16:22:54
Message: <3cab72ae@news.povray.org>
The mesh grass in my last post didn't really look very good IMO, so I tried
to make it denser and to add another light source, and I think it really
helped. However, it also increased the render time quite a bit, so that my
faked grass texture is faster now after all. I guess one can draw any
conclusions by now, but as many have said, each method will have its own
use.

Faked texture grass:
~~~~~~~~~~~~~~~~~~~~
Time for parse: 0 min.  0 sec.
Time for trace: 6 min.  3 sec.
Time total:     6 min.  3 sec.
Peak memory used:  0.36 MB


Real mesh grass:
~~~~~~~~~~~~~~~~
Time for parse:  0 min. 15 sec.
Time for trace: 14 min. 39 sec.
Time total:     14 min. 54 sec.
Peak memory used: 23.30 MB

Grass blades: 75^2*25^2 = 3515625


The grass texture looks a bit more boring with the second light source
added, because there's less contrast, but such things will always vary from
scene to scene.

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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Attachments:
Download 'grassreal2.jpg' (29 KB) Download 'grassfaked2.jpg' (21 KB)

Preview of image 'grassreal2.jpg'
grassreal2.jpg

Preview of image 'grassfaked2.jpg'
grassfaked2.jpg


 

From: Sir Charles W  Shults III
Subject: Re: UPDATE
Date: 3 Apr 2002 17:19:50
Message: <3cab8006$1@news.povray.org>
Ah, the upper picture is St. Augustine grass, and the lower is Bahia or
Zoysia...

Cheers!

Chip Shults
My robotics, space and CGI web page - http://home.cfl.rr.com/aichip


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From: Daniel Matthews
Subject: Re: Comparing mesh grass with faked grass (32+20 kbu)
Date: 3 Apr 2002 19:50:56
Message: <72719949.rKQ5TDuZKl@3-e.net>
Your fake looks good/best, but can you combine the two methods so that 
there is a little more shadow variation in the final image?

Rune wrote:

> I used TonyB's modified version of Gilles Tran's mesh grass to compare how
> mesh grass renders and looks compared to my faked grass.
> 
> Both images were rendered at 800x600 AA0.3, then scaled to half size
> before posting here.
> 
> Faked texture grass:
> ~~~~~~~~~~~~~~~~~~~~
> Time for parse: 0 min.  0 sec.
> Time for trace: 5 min. 58 sec.
> Time total:     5 min. 58 sec.
> Peak memory used:  0.36 MB
> 
> 
> Real mesh grass:
> ~~~~~~~~~~~~~~~~
> Time for parse: 0 min. 10 sec.
> Time for trace: 4 min.  8 sec.
> Time total:     4 min. 18 sec.
> Peak memory used: 15.09 MB
> 
> As you can see, my faked grass renders a bit slower. The real mesh grass
> renders quicker, it doesn't use particularly much memory, and it parses in
> almost no time. I expect that the fields of grass must be extremely huge
> before my faked grass becomes more efficient than mesh grass...
> 
> However, my grass looks rather different than the mesh grass. It has a
> softer look, which I rather like. I may be of course, that I just haven't
> been able to tweak the mesh grass to look good in my scene...
> 
> Ok, I really don't know what to conclude, so I'll just let it be up to
> you...
> 
> 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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From: Tony[B]
Subject: Re: UPDATE
Date: 3 Apr 2002 21:23:50
Message: <3cabb936@news.povray.org>
I suppose that, if anything, one can conclude that the mesh grass allows for
a greater variety of grass types and is actually 3D (casting shadows, etc.),
while the texture grass saves memory and rendertime. I would like to see
them combined somehow. Like a distance-based grass macro, that flows from
mesh to texture as distance increases. It'd be hard to get them to match and
figure a proper distance algorithm, though...


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From: Dave Dunn
Subject: Re: Comparing mesh grass with faked grass (32+20 kbu)
Date: 4 Apr 2002 10:48:07
Message: <3CAC7578.D6B4F9F8@aol.com>
Rune wrote:

> I used TonyB's modified version of Gilles Tran's mesh grass to compare how
> mesh grass renders and looks compared to my faked grass.

What struck me was the similarity of the mesh grass to the PDI "style" as seen
in Shrek, and the texture-based "faked" grass to Pixr's style for A Bug's Life.


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