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From: Invisible
Subject: You know you've been tracing too long when...
Date: 17 Mar 2008 06:18:07
Message: <47de536f$1@news.povray.org>
...you ask POV-Ray to draw a 40 megapixel image, it renders at roughly 2 
pixels per second, and you calculate how long it will take to render.

And then feel glad you're sitting down. (!)










40 megapixels = 40,000,000 pixels.
40,000,000 pixels / 2 pixels/second = 20,000,000 seconds.
20,000,000 seconds = 333,333 minutes.
333,333 minutes = 5,555 hours.
5,555 hours = 231.5 days.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*


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From: Invisible
Subject: Re: You know you've been tracing too long when...
Date: 17 Mar 2008 06:22:27
Message: <47de5473$1@news.povray.org>
Invisible wrote:
> ...you ask POV-Ray to draw a 40 megapixel image, it renders at roughly 2 
> pixels per second, and you calculate how long it will take to render.
> 
> And then feel glad you're sitting down. (!)

...ah, but if I use the new POV-Ray beta, it'll render TWICE AS FAST!! >:-D



Ooo, isn't that the one where Warp implemented physically correct 
hilights from area lights? I could use... uh... slow the render back 
down to where it's at now. :-S

DANMIT!! >_<

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*


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From: Invisible
Subject: Re: You know you've been tracing too long when...
Date: 17 Mar 2008 06:46:45
Message: <47de5a25$1@news.povray.org>
POV-Ray, POV-Ray, in the sky,
How you make my Athlon cry.
Eating lots of gigaFLOPS,
Burn each core until it stops.
POV-Ray, POV-Ray, in the sky,
How you make my PC die...

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*


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From: Warp
Subject: Re: You know you've been tracing too long when...
Date: 17 Mar 2008 07:35:02
Message: <47de6576@news.povray.org>
Invisible <voi### [at] devnull> wrote:
> Ooo, isn't that the one where Warp implemented physically correct 
> hilights from area lights?

  They are not physically correct. They are slightly closer to correct.

  Besides, the feature is not turned on by default. You have to turn it
on explicitly by using the 'area_illumination' keyword in the light_source
block.

-- 
                                                          - Warp


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From: Invisible
Subject: Re: You know you've been tracing too long when...
Date: 17 Mar 2008 07:44:52
Message: <47de67c4$1@news.povray.org>
Warp wrote:

>   They are not physically correct. They are slightly closer to correct.

Well, yeah.

>   Besides, the feature is not turned on by default. You have to turn it
> on explicitly.

But what I was saying is that I could turn it on - and thereby negate 
the advantage of an extra rendering core. [Although thinking about it, 
for such a small area light so far away from the shiny surfaces, it's 
probably not worth it...]

Is that not the POV-Ray way? As soon as you have more CPU power, you 
render more complex images and it *still* takes forever to finish? ;-)

Still, 10 years ago decoding MPEG video fast enough for realtime display 
required custom ASICs and cost a fortune. Today I have a desktop PC that 
can do it without loading one core to more than 10%. Tomorrow...?

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*


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From: Nicolas Alvarez
Subject: Re: You know you've been tracing too long when...
Date: 17 Mar 2008 10:11:49
Message: <47de8a35$1@news.povray.org>

> ...you ask POV-Ray to draw a 40 megapixel image, it renders at roughly 2 
> pixels per second, and you calculate how long it will take to render.
> 
> And then feel glad you're sitting down. (!)
> 
> 40 megapixels = 40,000,000 pixels.
> 40,000,000 pixels / 2 pixels/second = 20,000,000 seconds.
> 20,000,000 seconds = 333,333 minutes.
> 333,333 minutes = 5,555 hours.
> 5,555 hours = 231.5 days.
> 

40 megapixel? Hmm how much RAM is it eating? Last time I tried an image 
around that big, POV-Ray crashed.


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From: Doctor John
Subject: Re: You know you've been tracing too long when...
Date: 17 Mar 2008 10:21:11
Message: <47de8c67$1@news.povray.org>
Invisible wrote:
> POV-Ray, POV-Ray, in the sky,
> How you make my Athlon cry.
> Eating lots of gigaFLOPS,
> Burn each core until it stops.
> POV-Ray, POV-Ray, in the sky,
> How you make my PC die...
> 
:-D

John

-- 
I will be brief but not nearly so brief as Salvador Dali, who gave the
world's shortest speech. He said, "I will be so brief I am already
finished," then he sat down.


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From: Invisible
Subject: Re: You know you've been tracing too long when...
Date: 17 Mar 2008 10:31:19
Message: <47de8ec7$1@news.povray.org>
Nicolas Alvarez wrote:

> 40 megapixel? Hmm how much RAM is it eating? Last time I tried an image 
> around that big, POV-Ray crashed.

I have no idea. I haven't looked. I wouldn't expect it to be exceptional...

Assuming the image were exactly 40,000,000 pixels (which it isn't), I 
would expect roughly 40,000,000 x 3 bytes = roughly 114 MB. You'd have 
to have a fairly underpowered machine to not be able to spare 114 MB. 
(Especially given the sequential access - surely most of it would just 
be paged out?)

Let me put it this way: I set POV-Ray running, set the processor 
affinity so it only uses one core, and then went off to play Farcry. 
There was no noticable performance drop. [But then, Farcry is probably 
nailing my GPU more than the CPU...]

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*


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From: Nicolas Alvarez
Subject: Re: You know you've been tracing too long when...
Date: 17 Mar 2008 11:21:27
Message: <47de9a87$1@news.povray.org>

> (Especially given the sequential access - surely most of it would just 
> be paged out?)

Not if you're using the preview window ;)

In fact, I think if preview is off, it only needs width*2 memory (plus 
width*something used by libpng), not width*height. But I'm not too 
sure... Warp would probably know, he has poked with the source more than 
me :)


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From: Invisible
Subject: Re: You know you've been tracing too long when...
Date: 17 Mar 2008 11:27:04
Message: <47de9bd8$1@news.povray.org>
>> (Especially given the sequential access - surely most of it would just 
>> be paged out?)
> 
> Not if you're using the preview window ;)

Ah yes, you're right - it might actually need 2x 114 MB = 228 MB. [Still 
peanuts compared to Farcry, I would expect.] And somewhat less 
sequential access.

No matter. My PC has an insane 3 GB of dual-channel RAM to play with... >:-D

> In fact, I think if preview is off, it only needs width*2 memory (plus 
> width*something used by libpng), not width*height. But I'm not too 
> sure... Warp would probably know, he has poked with the source more than 
> me :)

Maybe.

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*


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