Le Sun, 17 May 2009 15:07:40 +0200, Nekar Xenos <nek### [at] gmailcom> a  


> Keep up the good work!
>
> It would be nice if this could be incorporated into my nxplanets planet  
> creator (on the Pov-Ray object collection) or something similar.   =]
>
> Does you system hide stars in daytime and show them at night?
>
> -Nekar Xenos
>
>
>
> "Bruno Cabasson" <bru### [at] cabassoncom> wrote in message  
> news:op.us5o01drm1sclq@pignouf...
>> Le Sun, 19 Apr 2009 23:20:47 +0200, Bill Pragnell

>>
>>> Tricky things, clouds. All my previous experiments with media clouds
>>> have been
>>> slow, unrealistic, and fiddly. Gilles' df3 technique is sly, and his
>>> example
>>> images beautiful. However, I've always wanted a cloud macro that will
>>> 'just
>>> work' in a scene, without the need for external tools and without the
>>> memory
>>> consumption of hi-res df3s.
>>>
>>> This image is a decent result from a set of macros I've recently been
>>> developing
>>> - it rendered in ~30 mins on my 1.8GHz macbook, which I think is very
>>> good for
>>> 'pure' object-pattern-based media (this is without aa - unfortunately  
>>> it
>>> takes
>>> a lot longer with aa).
>>>
>>> Using a blob as the pattern template makes the rendering much quicker,
>>> and
>>> lowering the media aa_level is also a great speedup I'd never tried
>>> before. My
>>> basic cloud macro currently has 11 parameters, which sounds like a lot,
>>> but this
>>> includes location and size, turbulence, solidity and so on, which makes
>>> tweaking
>>> a lot easier. I've also got a quality parameter, the lowest setting of
>>> which
>>> just uses the solid blob objects - very handy for shape and location
>>> checks
>>> (and also looks pretty surreal!).
>>>
>>> Anyway, this is a wip so I'll post more interesting results as I get
>>> them...
>>
>>
>> Hello POVers.
>>
>> Perhaps some people here will remember me. It's a loooong time I was not
>> present among the POV community. Real life took me away from you  
>> (sigh...)
>> for months and from my POV-related projects. The main project is still
>> alive and is called TerraPOV. It deals with landscape scenes, inspired  
>> by
>> Terragen, and I was mainly focusing on atmosphere and cloudscapes, which
>> is a difficult exercise if you want to have quite-realistic results. I  
>> had
>> some encouraging renders. I came back on POV forums and to TerraPOV
>> recently. My new machine (overclocked Q6600) allows a step forward. I  
>> feel
>> like I can say something on this thread about clouds.
>>
>>
>> TerraPOV has 3 major dimensions:
>>
>>     1) Atmospheres & cloudscapes/single could
>>     2) Terrain generation/texturing
>>     3) Preview & other user-friendly features
>>
>> I also remember that I promessed you a tutorial for the principles  
>> ruling
>> TerraPOV's atmophere & clouscape system. I will keep my promess soon.
>>
>> Here are a few things I can get, among them is the last render I got  
>> last
>> night (atmo_demo5bis.png and atmo_demo5ter.png), based on a previous  
>> test
>> scene, but with higher settings. The problem I have now is to find a
>> solution for multi-layer cloudscapes because monte-carlo integration can
>> only be in a single container. Until now, cloud layers are contained
>> within spherical shells. I am currently trying to find a way to have
>> multiple layers (2 or 3 are enough for most cases) within a single shell
>> container without setting too many intervals or samples for the media.
>>
>> The last picture 'atmo_demo5ter.png' is the same as 'atmo_demo5bis'  
>> shows
>> what can happen with 2 layers, which is more visible at low elevations
>> (resp 3deg and 18deg). The bottom layer is dark because integration only
>> occurs within the shell and does not take into account what happens  
>> above.
>> You can see that the top layer bahaves as It could be expected.
>>
>>
>> I am very happy to be back, and I sincerely hope I can get regular
>> availability and time here. It is always a nice pleasure to be with  
>> people
>> around here.
>>
>>
>> Bruno
>>

>> http://www.opera.com/mail/
>

Considering stars can be an interresting feature for TerraPOV. I'll keep  
it in mind. How I see this at first sight: Their very low lightness can be  
taken into account, making them invisible (negligible contribution, as in  
normal life). In TerraPOV, when the sun is low - near or below horizon -  
the scene gets darker. A brightness parameter compensates this in order to  
have sufficient illumination. This factor can be applied to the brightness  
of stars that will then appear automatically (provided at least one ray  
intercepts the object or whatever represents the star).

Next TerraPOV article is being prepared and nearly ready. I hope I can  
post it tomorrow.

Bruno

-- 

http://www.opera.com/mail/

Post a reply to this message