"Warp" <war### [at] tagpovrayorg> wrote in message 
news:43f2e627$1@news.povray.org...
> Tek wrote:
>> And that's about it. What do you think?
>
>   It's looking quite good.
>
>   However, there's still some non-photorealistic quality to it,
> even though I can't put my finger on it.


  The bounding box for the immediate fire/flames from the top of the volcano 
shows too much?

   Not sure if anyone else can see this?


   ~Steve~

Post a reply to this message

"Christoph Hormann" <chr### [at] gmxde> wrote in message 
news:dsv5jr$n3f$1@chho.imagico.de...
> Tek wrote:
>>
>> Still to do:
>> -The aforementioned resurrection of the lava rivers
>
> I think you will have to modify the terrain geometry for that.
>
>> -fix that eliptical bug round the top of the volcano (anyone know why 
>> overlapping media-containers don't play nice together?)
>
> Do you have sufficient max_trace_level?

  Ah, great minds...

  ~Steve~



> Christoph

Post a reply to this message

Mmmm, I like it...

Post a reply to this message

Yeah that's the elliptical error I mentioned. I can see it, it's a mistake, 
it will be fixed. Though I'm annoyed pov can't handle having 2 
media-containers overlapping without artefacts.

-- 
Tek
http://evilsuperbrain.com

"St." <dot### [at] dotcom> wrote in message news:43f37a88@news.povray.org...
>
> "Warp" <war### [at] tagpovrayorg> wrote in message 
> news:43f2e627$1@news.povray.org...
>> Tek wrote:
>>> And that's about it. What do you think?
>>
>>   It's looking quite good.
>>
>>   However, there's still some non-photorealistic quality to it,
>> even though I can't put my finger on it.
>
>
>  The bounding box for the immediate fire/flames from the top of the 
> volcano shows too much?
>
>   Not sure if anyone else can see this?
>
>
>   ~Steve~
>
>
>
>
>

Post a reply to this message

Well, the max trace level I'd need to show that bit correctly would be at 
most 6, and my max trace is currently 80!

The problem seems to simply be I have 2 different media-containers that 
happen to overlap, it seems pov carves a hole out of one of them where it 
finds the other. I was getting some horiffic errors from the flying lava 
until I differenced it with the smoke's media container. The errors looked 
like shadows through the media but bright white. Anyway my experience is 
media "just does that sometimes" and you need to help it understand where 
the division is between your surfaces by using differences and such, I was 
just hoping someone understood the technical aspect of this better than me. 
i.e. I can work round it, but I'd like to know why I have to :)

-- 
Tek
http://evilsuperbrain.com


"Christoph Hormann" <chr### [at] gmxde> wrote in message 
news:dsv5jr$n3f$1@chho.imagico.de...
> Tek wrote:
>>
>> Still to do:
>> -The aforementioned resurrection of the lava rivers
>
> I think you will have to modify the terrain geometry for that.
>
>> -fix that eliptical bug round the top of the volcano (anyone know why 
>> overlapping media-containers don't play nice together?)
>
> Do you have sufficient max_trace_level?
>
>> -steam wherever lava touches water/snow
>> -...and something else... the left side of the image looks too calm, any 
>> suggestions?
>
> Maybe some landslide - would be reasonable to occur during a vulcanic 
> eruption...
>
> Concerning realism - it is extremely difficult to achieve an impression of 
> realism for the viewer with such an image where hardly anyone has a real 
> life experience to compare to.  None the less i think the smoke is too 
> fluffy.
>
> Christoph
>
> -- 
> POV-Ray tutorials, include files, Landscape of the week:
> http://www.imagico.de/ (Last updated 31 Oct. 2005)
> MegaPOV with mechanics simulation: http://megapov.inetart.net/

Post a reply to this message

This is a great improvement, Tek!

Still, some unconfortable feelings. Although the shape of the volcano is
much better, I think the slope is too steep. Volcano slopes are mainly made
up of rubble and the "maximum angle of repose" of loose material is about 37
degrees. This concerns all kind of slopes like screes, or dunes too. Your
slope (to the left) is about 50 degrees.

Your underwater view is impressive indeed. Still, I feel that the flow is
too thin to be really believable and natural looking. I would expect a more
massive "wall" of lava with those fiery blobs sticking out.

Sorry for these comments! They come from my professional background mainly.
You have created a great image already!

Thomas

Post a reply to this message

Thomas de Groot wrote:
> up of rubble and the "maximum angle of repose" of loose material is about 37
> degrees. This concerns all kind of slopes like screes, or dunes too. Your

Aren't the Pyramids of Egypt built at a 37 degree angle as well?

...Chambers

(Sorry, a bit OT)

Post a reply to this message

This is looking much better, the sky looks better now you have made the blue
darker nearer the top and this (plus other changes I am sure) makes the
water looks much better too. The darker colour of the smoke is also an
improvement.

Sean

Post a reply to this message

> The problem seems to simply be I have 2 different media-containers that
> happen to overlap, it seems pov carves a hole out of one of them where it
> finds the other.

The problem, I believe, is that your sampling parameters aren't high enough.
POV-Ray isn't taking enough samples of the media, so you're getting
incorrect results. When there's only one container, the result looks good
enough that you don't have to worry about it - but when a ray passes through
two containers, the places the samples are taken change, so you get a
*different* incorrect result.

As you improve your sampling parameters ("samples n" where n is high (start
at 10 or so and work your way up)), the effect should diminish, but the
render will also get slower.

If you can put both medias into one container, you can eliminate the problem
that way - but you'll be sampling both medias everywhere, which will hurt
performance.

 - Slime
 [ http://www.slimeland.com/ ]

Post a reply to this message

That's certainly a problem I've seen before, though I suspect that's not it 
because I've already cranked the samples up pretty high. Having said that, 
the difference in size between the 2 containers is vast, so maybe even with 
a lot of samples they're still quite coarse in the overlapping area...

But you're right, if I up the number of samples I can tell if that's the 
problem... a few hours later when it finishes rendering... :)

-- 
Tek
http://evilsuperbrain.com

"Slime" <fak### [at] emailaddress> wrote in message 
news:43f548d2$1@news.povray.org...
>> The problem seems to simply be I have 2 different media-containers that
>> happen to overlap, it seems pov carves a hole out of one of them where it
>> finds the other.
>
> The problem, I believe, is that your sampling parameters aren't high 
> enough.
> POV-Ray isn't taking enough samples of the media, so you're getting
> incorrect results. When there's only one container, the result looks good
> enough that you don't have to worry about it - but when a ray passes 
> through
> two containers, the places the samples are taken change, so you get a
> *different* incorrect result.
>
> As you improve your sampling parameters ("samples n" where n is high 
> (start
> at 10 or so and work your way up)), the effect should diminish, but the
> render will also get slower.
>
> If you can put both medias into one container, you can eliminate the 
> problem
> that way - but you'll be sampling both medias everywhere, which will hurt
> performance.
>
> - Slime
> [ http://www.slimeland.com/ ]
>
>

Post a reply to this message