Would it be possible to speed radiosity by putting the main scene file
in RAM disk so that the .rca file would be in RAM too?

I have 256MB RAM (98 SE) and when rendering a radiosity scene there
seems to be too much disk activity (it all should fit in RAM with room
to spare).

How does one make RAM disk in win98 :)

_____________
Kari Kivisalo

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Kari Kivisalo <voi### [at] devnull> wrote:
: Would it be possible to speed radiosity by putting the main scene file
: in RAM disk so that the .rca file would be in RAM too?

  I don't think the values are read from the .rca-file, only written to.
The only situation where the values are read is once with continued traces.
In this case putting the .rca file in memory wouldn't help too much.

  I might be wrong, of course.

-- 
#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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> How does one make RAM disk in win98 :)

have a look on your win98 start up disk, it creates a ram disk - there are
also some helpful txt files in your c:\windows directory (that's if you
haven't deleted them :)


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On Tue, 03 Jul 2001 01:27:07 +0300, Kari Kivisalo <voi### [at] devnull>
wrote:

>How does one make RAM disk in win98 :)

You don't. You make it in DOS and you run Win98 from DOS, as you would
normally. If I were you, though, I'd rather assign more disk cache
than make a ramdisk.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg

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> >How does one make RAM disk in win98 :)
>
> You don't. You make it in DOS and you run Win98 from DOS, as you would
> normally. If I were you, though, I'd rather assign more disk cache
> than make a ramdisk.

although if you have buckets of ram, a small RD can be very useful, its one
of those things your not sure you will use till you have one, then cannot
live without it


--
Rick

Kitty5 WebDesign - http://Kitty5.com
Hi-Impact database driven web site design & e-commerce
TEL : +44 (01625) 266358 - FAX : +44 (01625) 611913 - ICQ : 15776037
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Kari Kivisalo wrote:

> Would it be possible to speed radiosity by putting the main scene file
> in RAM disk so that the .rca file would be in RAM too?

Not a answer to that precise point, but slicing the render into smaller
chunks (+er0.1, +er0.2 etc.) helps a lot keeping the memory use in check
for radiosity images. I would never have been able to render 3200*2400 rad
pics without it (and I've never noticed visible artefacts due to the
resuming).

G.

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Gilles Tran wrote:
> 
> Not a answer to that precise point, but slicing the render into smaller
> chunks (+er0.1, +er0.2 etc.) helps a lot keeping the memory use in check
> for radiosity images. I would never have been able to render 3200*2400 rad
> pics without it (and I've never noticed visible artefacts due to the
> resuming).
> 

I always found such artefacts quite noticeable, also the increased memory
use for larger renders seems quite moderate to me (unless of course you
change the radiosity settings which is often useful for a larger render)

I recently did a render at 2400x1350 which took 378 Mb instead of ~260 Mb
at 1024x567 (same settings).  

Finally the split render would take longer because radiosity samples are
taken several times, and render time IMO is often more of a problem than
memory use.

Christoph

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Christoph Hormann wrote:

> I always found such artefacts quite noticeable,

I've read this many times but was never able to observe it in renders using
high-quality radiosity settings. In fact, I once made a "difference" picture to
test it by substracting the "non-stop" image from the "stop and resume" image
and I really had to raise the contrast level to see a few odd pixels here and
there, unnoticeable otherwise.

> I recently did a render at 2400x1350 which took 378 Mb instead of ~260 Mb
> at 1024x567 (same settings).

I've noticed this also, and it's quite fortunate that the relationship between
memory use and image size is not linear...

> Finally the split render would take longer because radiosity samples are
> taken several times, and render time IMO is often more of a problem than
> memory use.

I had tested this some time ago. The non-stop render took 68s and used 41 Mo
(160 x 120, no aa). I made three slices +er0.3 +er0.6 and final. Each slice took
14-15 Mo and the cumulated render time was 22+24+20 = 66s.
Also, if the image makes a large use of the swap file, the render time suffers a
lot. Actually, I started slicing renders because Pov kept running out of memory
on large images, and the slicing took care of the problem.

G.


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**********************
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