Hiya, well, this is my first use of POV-Ray in a few years now (probably 3
years, wow, it's been a while), so I've been catching up on a lot of
features that were never in the POV-Ray I knew.  This is just a test of
using Photons and Radiosity together... it took about 20 minutes to render
which doesn't seem too bad, but I'm guessing the "stripe" effect in the
photons is just because I haven't set the count high enough?

For some reason, and this is probably a little off-topic for this group, I
can't get POV-Ray to use 100% of CPU time in Windows, regardless of the
render priority (I set it to the highest).  I'm not sure if it's because I
have two processors and they're sharing some of the load automatically (the
second processor does tend to do some work while rendering but I'm not sure
if it's POV-Ray or something else, I'd have to check).

The radiosity works really well (tried a few images and simple tests of
boxes and what-not).  It's so much fun to be able to use radiosity now... in
the past it was just too painful!

Anyway, I'm having lots of fun and might try "radiositying" some objects
from *gasp* MAX.

Lance.

thezone.firewave.com.au
www.firewave.com.au

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Attachments:
Download 'photon_tracing.jpg' (78 KB)

Preview of image 'photon_tracing.jpg'

You pick up quick! That's a very beautiful render! :)

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Wow, excellent photons, especially for your first time!

IIRC POV is single-threaded.  Could it be that the system resource
report just isn't accurate?  I don't trust those things 100%, they tend
to disagree with one another.

-- 
David Fontaine  <dav### [at] faricynet>  ICQ 55354965
My raytracing gallery:  http://davidf.faricy.net/

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Tony[B] wrote:
> You pick up quick! That's a very beautiful render! :)

Why thank you :)

I think I've improved a lot since I last used POV... in a lot of ways.  Now
I can apply a lot of what I've learnt and hopefully create something good
looking :D

I've already started on an idea for an image I'm calling Isis.  Early stages
yet though, and it's going to take a lot of work, heh.

Lance.

thezone.firewave.com.au
www.firewave.com.au

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"David Fontaine" <dav### [at] faricynet> wrote in message
news:3BDCC487.D8433C6B@faricy.net...
> Wow, excellent photons, especially for your first time!

Maybe I was just lucky :)  I think setting the count to 2,000,000 was a good
start ;)

> IIRC POV is single-threaded.  Could it be that the system resource
> report just isn't accurate?  I don't trust those things 100%, they tend
> to disagree with one another.

I'm not sure, with RC5 running I can get both processors doing 100% (if not
with a little bit or kernel action here and there).  I'll have to
investigate it further.  AFAIK POV-Ray is single-threaded as well, but even
still, setting it to the highest thread priority should get it using 100% of
one processor.  I'll have to try manually setting it in the task manager on
pvengine.

Lance.

thezone.firewave.com.au
www.firewave.com.au

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Sweet image, everyone comes back to POV :P


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Rick

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POV-Ray News & Resources - http://Povray.co.uk
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"Lance Birch" <-> wrote...
> Hiya, well, this is my first use of POV-Ray in a few years now (probably 3
> years, wow, it's been a while), so I've been catching up on a lot of
> features that were never in the POV-Ray I knew.  This is just a test of
> using Photons and Radiosity together... it took about 20 minutes to render
> which doesn't seem too bad, but I'm guessing the "stripe" effect in the
> photons is just because I haven't set the count high enough?

Increasing the photon jitter (up to 1.0) should get rid of that, but it
might introduce some noise into the caustics... overall, high jitter should
work well with this scene, though.

-Nathan

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Nathan Kopp wrote:
> Increasing the photon jitter (up to 1.0) should get rid of that, but it
> might introduce some noise into the caustics... overall, high jitter
should
> work well with this scene, though.

Thanks, I did and it made a big difference :)

Lance.

thezone.firewave.com.au
www.firewave.com.au

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After a little experimenting I found that it was simply that Windows 2000
was sharing the pvengine process across both processors, so that it could
load balance other processes better.  The affinity by default is set on CPU0
+ CPU1, even if the process only contains a single thread.  As more
processes are set to a specific processor, it throttles the other processes
more towards the opposite processor to ensure they're being balanced in
terms of cycles.  I tried forcing pvengine to affinity CPU0, and it does
take up 100-99% of that processor, so the thread is getting the equivilant
of 100% of a processor's time.  As soon as it's switched back to CPU0 + CPU1
it balances again.

The process shows as taking up 50% of the total CPU usage, which is correct.
(graph of the cycles from switch affinty from CPU0 to CPU0 + CPU1 included
just for fun ;)  Even with distributed.net running it still gets 50-49% of
the total usage, while distributed.net is throttled to the other processor,
and gets the remaining 49-50%.  Works well :)

Anyway, that's getting really off-topic (kinda), so back to the image.

I tried raising the jitter from 0.3 to 1 as was suggested by Nathan and it
made the image look a lot better, but it was getting dark and light patches,
so I figured it still needed more photons.  I bumped the count up to 3
million from 2 million, but it was still patchy, so I went to 4 million,
then 5 and then 6 million (heh) and it seems to have smoothed it out a fair
bit.  I probably should read the documentation a little more carefully...
maybe there's an option I've missed to help a little bit, but then again
maybe there isn't (I guess that's what jitter is for really), so I'm happy
with pushing the count up.  It's still a little patchy in some of the more
sparse areas of the shadows, but no where near as bad as it was :)

I've also replaced the standard light with an area light and it looks a lot
better (I'm a big fan of soft shadows, heh) but there is an atefact I've
having difficulties getting rid of (the harsh edge to the shadows that
appears on the shadows of the first and second torii on the left side of the
image, just where it goes really soft).  Any ideas how to get rid of it?  I
tried using 32x32 lights in the area light too (instead of the 18x18 in that
image) but it was still there :/

Anyway, I can see I'm going to have a LOT of fun with photons and radiosity!

Lance.

thezone.firewave.com.au
www.firewave.com.au

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Attachments:
Download 'photon_tracing_2.jpg' (71 KB) Download 'affinity_graph.gif' (5 KB)

Preview of image 'photon_tracing_2.jpg'

Preview of image 'affinity_graph.gif'

The image looks very good.
  However, there's something strange there. I think that you clearly wanted
to make glass torii. However, for some reason they look like made of plastic
instead.
  What is their ior? Also perhaps the highlights should be sharper.

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -

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