Heres a render of Gille's Tran's wonderful cloudscape4 scene in p.b.s-f
http://news.povray.org/povray.binaries.scene-files/14509/

After some experimentation with the media settings, I found the "long test"
setting to offer the best quality versus speed:
intervals 3 samples 10, 20 confidence 0.9999 variance 1/10  // long test

The image was rendered at 1400x1050 at 48-bits. Then I scaled it down and
cropped it in Photoshop.
Applying slight gaussian blur (0.5 pixel radius) took care of any remaining
graininess.

I rendered this using my distributed rendering software I'm developing.
Rendering time was about 1 hour on two machines: a P4 2.72GHz (Windows
2000/Cygwin) and an AthlonXP 1.733GHz (Linux )
(the two machines are about equal in rendering speed, FYI)

Thanks for the great contribution Gilles! Do you have any more cool scene
files to release? :)
I bet this would look great in stereo...

Regards,
George Pantazopoulos

Post a reply to this message

Attachments:
Download 'GTClouds_4.png' (276 KB)

Preview of image 'GTClouds_4.png'

de news: 3ea431e6@news.povray.org...
> Thanks for the great contribution Gilles! Do you have any more cool scene
> files to release? :)
Nice to see that bit of code used!

About other cool scene files that include clouds, see the thumbnails below:

Good news: it's quite fast (i.e. fast enough for normal scene work)
Bad news: I still have to work on more demo pictures before I release the
code

...but that will be soon :D

G.

--

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

Post a reply to this message

Attachments:
Download 'clouds1.jpg' (14 KB) Download 'clouds2.jpg' (9 KB)

Preview of image 'clouds1.jpg'

Preview of image 'clouds2.jpg'

Gilles Tran wrote:
> 
> [...]
> 
> About other cool scene files that include clouds, see the thumbnails below:
> 
> Good news: it's quite fast (i.e. fast enough for normal scene work)
> Bad news: I still have to work on more demo pictures before I release the
> code
> 
> ...but that will be soon :D

That looks very promising.  Are those also suited for large size renders?
As you know media clouds usually have serious problems here.

I also like the terrain.  Looks like made with isosurfaces...

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 28 Feb. 2003 _____./\/^>_*_<^\/\.______

Post a reply to this message

3EA4FFF4.13B5D033@gmx.de...
> That looks very promising.  Are those also suited for large size renders?
The goal is to make the technique suitable in quality and render times for
large size renders. I've tested them at 1600*600 and 1600*1200 (6 hours each
on my P4) which is already very acceptable considering that these are pretty
complex scenes with radiosity, media and isosurfaces, but I'm doing further
tests. It won't be 100% perfect and will have some limitations but I hope it
will be usable.

> I also like the terrain.  Looks like made with isosurfaces...
The terrain is a function-generated heigh-field and the mountain is a big
hill of isosurfaces. Both render quite fast too. These demo scenes will be
available of course, part of the next Oyonale update.

G.


--

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

Post a reply to this message

Gilles Tran wrote:
> 
> > That looks very promising.  Are those also suited for large size renders?
> The goal is to make the technique suitable in quality and render times for
> large size renders. I've tested them at 1600*600 and 1600*1200 (6 hours each
> on my P4) which is already very acceptable considering that these are pretty
> complex scenes with radiosity, media and isosurfaces, but I'm doing further
> tests. It won't be 100% perfect and will have some limitations but I hope it
> will be usable.

6 hours sounds good.  Do they interact with the light (i.e. cast shadows
etc.)?

> > I also like the terrain.  Looks like made with isosurfaces...
> The terrain is a function-generated heigh-field and the mountain is a big
> hill of isosurfaces. Both render quite fast too.

Using a heightfield for the background terrain is surely an efficient
solution if you can afford it memory-wise.  With a large render this will
always be tricky though - the higher the render resolution the stronger
the differences between foreground and background will get in the result. 
In case of your sample this won't look too artificial since the step from
foreground to background is quite large but this is a real problem when it
is more fluent.

In my experience the most serious disadvantage of using isosurfaces in
such situations is the strong slowdown you get when using radiosity.  It
could be worth trying variable radiosity settings here (i have made tests
with that some time ago but not with landscape scenes).

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 28 Feb. 2003 _____./\/^>_*_<^\/\.______

Post a reply to this message

3EA51489.A067C415@gmx.de...
> 6 hours sounds good.  Do they interact with the light (i.e. cast shadows
> etc.)?
Yes, these are media clouds and they cast shadows (see the shadowing on the
top of the mountain in the attached image). Note that a good deal of the
render time was taken by isosurfaces and other media elements, the clouds
themselves are relatively fast, and particularly, they're very fast to test,
a few seconds at 320*240 using intervals 1 and no aa, which makes scene
development quite easy. But, as I said, I have to test the technique at
higher resolutions, though it should be scalable.

> In my experience the most serious disadvantage of using isosurfaces in
> such situations is the strong slowdown you get when using radiosity.

There's no perfect solution I fear. Function-based HF are good and render
fast but they require a lot of memory and may show artefacts. I've favouring
this technique though, because for many terrains and when the view is
horizontal it's possible to tile the same HF over and over at different
sizes and get away with it. Plants and complex textures can hide the
artifacts pretty well, even at high-res... In other cases (snow or mineral
desert with no plant cover), "true" isosurfaces are the only good solution
for the foreground.

G.

--

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

Post a reply to this message

Attachments:
Download 'clouds1_detail.jpg' (16 KB)

Preview of image 'clouds1_detail.jpg'

AAaaaaaah :-))
Thanks Gilles

That's so cool!
I have been fighting with media clouds for a long time, getting mean results
unless with prohibitive render times which make tweaking endless.
It's a very good new.
The clouds on the lower image seem more consistent -particularly shadowed
zones- than what I get.
Is atmosphere a media as well?

3ea4fe1f@news.povray.org...

>
> ...but that will be soon :D
>
Well, say eerrrr... yesterday?
Marc

Post a reply to this message