Kenneth <kdw### [at] earthlinknet> wrote:
> Warp <war### [at] tagpovrayorg> wrote:

> >   Just use POV-Ray 3.7 (when it comes out; if you are using Windows, you
> > can try the beta).
> >
>  I'm still trying to understand v3.6.1 ALPHA!  ;-)

  I didn't understand that.

-- 
                                                          - Warp

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Kenneth wrote:
> Warp <war### [at] tagpovrayorg> wrote:
> 
>>   Just use POV-Ray 3.7 (when it comes out; if you are using Windows, you
>> can try the beta).
>>
>  I'm still trying to understand v3.6.1 ALPHA!  ;-)
> 
> Ken
> 
> 

3.6.1a is not actually 3.6.1 Alpha, it's a bug-fix release for 3.6.1. 
So they could have called it 3.6.2, or 3.6.1.1, but went with 3.6.1a :)

...Chambers

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Kenneth spake:

> Stefan Viljoen <spamnot@<removethis>polard.com> wrote:
> 
>> I have one processor, and I
>> use  a "segments of two" approach when dual-core rendering - one virtual
>> CPU gets the "top" the other the "bottom". If one finishes before the
>> other, the remaining part is again divided by two, etc.
>>
>  Can you explain that in more detail?  Sounds fascinating (and completely
> unknown to me.) Thanks!

Tsk tsk Warp... he did ask, didn't he? And, as far as I know, 3.7 is not yet
available for Linux?

Hi Kenneth

For a detailed explanation, take a look at the image I submitted to Paul
Bourke at Swinburne univ, which was rendered on a "farm" of Alpha CPU based
systems, and the article he wrote about it:

http://astronomy.swin.edu.au/~pbourke/raytracing/parallel/

Basically, you use PovRay INI file statemens to restrict a certain instance
of PovRay to only rendering a part of the scene. With any multi-core or
multi-processor system you can make this as complicated as you want, I just
usually use horisontal segments, for simplicity. The idea is like any
co-operative effort - one core / CPU does one part of the image, another
does the next, etc. If one finishes before the other, the work assigned to
the remaining CPUs is redivided, and the "free" CPU again gets part of the
remaining work.

Get the idea? The floating point load is thus shared out among many
"workers", and, just like in a human team, it means the problem is solved
much more quickly. Each CPU / core does its part, and then everybody has to
work less to solve the remainder of the problem. 

Figuratively, the problem is decimated until it is solved, by assigning and
re-assigning CPUs / cores as the problem is reduced.

Thus, you can literally raytrace images in hours or days that would have
taken a uni-core or single CPU system weeks or months to finish.

For example, the image at the link above was attempted to be traced by me -
after about two weeks on my old 400 MHz PC about 10 lines of the 480 I
needed were done. I sent it to Paul at Swinburne University in Australia
and he did it on... I think it was 32 machines in about 10 or 12 hours.

Feel free to drop me a mail at spamnot@<removethis>polard.com if you want
some examples.

Kind regards,

Stefan Viljoen

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Stefan Viljoen <spamnot@ <removethis>polard.com> wrote:
> Tsk tsk Warp... he did ask, didn't he? And, as far as I know, 3.7 is not yet
> available for Linux?

  But what I am thinking is that the "manual parallelization" of pov3.6 is
not only a real memory hog (rendering takes as much memory as many instances
of POV-Ray you run) but is also quite cumbersome and difficult, requiring
third-party tools and whatnot. I was thinking that instead of teaching him
the really hard way of doing it, the better way would be to wait for pov3.7
which automatically uses all the available processors in the computer without
the user having to do anything special to achieve that, and additionally
POV-Ray will not take basically any extra memory because of that.

-- 
                                                          - Warp

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Warp spake:

> Stefan Viljoen <spamnot@ <removethis>polard.com> wrote:
>> Tsk tsk Warp... he did ask, didn't he? And, as far as I know, 3.7 is not
>> yet available for Linux?
> 
>   But what I am thinking is that the "manual parallelization" of pov3.6 is
> not only a real memory hog (rendering takes as much memory as many
> instances of POV-Ray you run) but is also quite cumbersome and difficult,
> requiring third-party tools and whatnot.

You are absolutely correct, of course.

> I was thinking that instead of 
> teaching him the really hard way of doing it, the better way would be to
> wait for pov3.7 which automatically uses all the available processors in
> the computer without the user having to do anything special to achieve
> that, and additionally POV-Ray will not take basically any extra memory
> because of that.

Which now is his choice - he is not forced to wait for 3.7 to utilise his
hardware / prospective hardware for parallel rendering, and can start
fiddling with it immediately, with a current Linux / Unix version of POV. 

Of course 3.7 will be the ideal! Any idea when the Linux version will be
released?

Kind regards,
-- 
Stefan Viljoen
Software Support Technician / Programmer
Polar Design Solutions

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Hash: SHA1

Stefan Viljoen <spamnot@ wrote:
> Of course 3.7 will be the ideal! Any idea when the Linux version will be
> released?
> 
	Except that from all I've heard it won't be able to take advantage
of multiple computers in a network, only multiple cores or CPUs in
the same computer. However, it would probably be easier to create a
patch for distributed rendering than it is right now.

		Jerome

PS: Note that it might be simpler to use pvmpov rather than the
manual splitting approach (at least once you've got it running). Not
having used it myself, I can't say how hard it is or what kind of
quality issues there are (eg with radiosity and media), but it might
be worth a try.
http://pvmpov.sourceforge.net/

- --
******************************
*      Jerome M. Berger      *
*  mailto:jeb### [at] freefr   *
*  http://jeberger.free.fr/  *
******************************
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>         Except that from all I've heard it won't be able to take advantage
> of multiple computers in a network, only multiple cores or CPUs in
> the same computer. However, it would probably be easier to create a
> patch for distributed rendering than it is right now.

  The source has not only been heavily reworked for SMP but there has
naturally been a strong attention to rendering distributed over a
network. It doesn't necessarily mean that the final 3.7 will have
network rendering support, but it will make it easy to add such a
support afterwards.

-- 
                                                          - Warp

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Warp <war### [at] tagpovrayorg> wrote:
> Kenneth <kdw### [at] earthlinknet> wrote:
> > Warp <war### [at] tagpovrayorg> wrote:
>
> > >   Just use POV-Ray 3.7 (when it comes out; if you are using Windows, you
> > > can try the beta).
> > >
> >  I'm still trying to understand v3.6.1 ALPHA!  ;-)
>
>   I didn't understand that.
>

My feeble attempt at humor.  beta... alpha...??  Gee, tough crowd! (as they
say in the comedian biz.)

What I meant by my hilariously funny (??) rejoinder was, I'm still valiantly
working through the learning curve of v3.6.1, and don't yet feel confident
enough to tackle the beta version of 3.7 ( or the beta version of anything,
for that matter.)  If I ran into a problem, I really wouldn't know if it was
just me, or if it was some still-in-development part of the software. A bit
of paranoia there, I suppose. Best for me to play it safe, and wait until
3.7 matures.

Ken

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Kenneth <kdw### [at] earthlinknet> wrote:
> What I meant by my hilariously funny (??) rejoinder was, I'm still valiantly
> working through the learning curve of v3.6.1, and don't yet feel confident
> enough to tackle the beta version of 3.7

  There's no difference between the two, from a user point of view.
It's not like you would have to learn new things in order to use 3.7.
Whatever makes you think that?

-- 
                                                          - Warp

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Warp <war### [at] tagpovrayorg> wrote:
> Kenneth <kdw### [at] earthlinknet> wrote:
> > What I meant by my hilariously funny (??) rejoinder was, I'm still valiantly
> > working through the learning curve of v3.6.1, and don't yet feel confident
> > enough to tackle the beta version of 3.7
>
>   There's no difference between the two, from a user point of view.
> It's not like you would have to learn new things in order to use 3.7.
> Whatever makes you think that?
>
> --
>                                                           - Warp

Actually, I didn't realize that!  (I thought new *experimental* things might
have been added into v3.7) My confidence is RESTORED! ;-)  I'll give 3.7
beta a try.

Ken

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