That would make sense if its using pyramid maps as a base for its
lookup. Once you read the top level of the map, you can't get any more
optimization out of it. So if the map scrolls 20 times in the same
pixel, its 20 lookups. 40 times, 40 lookups. No more help from the
pyramid. Back to brute force sampling.
-brad
kim aldis wrote:
I'm going from memory here but I recall that with elliptical filtering
render times can vary wildly dependant upon the amound of compression of the
visible image in screen space. I seem to remember that, for example, on
landscapes the render time would go through the roof toward the horizon of a
textured landmass.
kim(at)cg-soup.com
kim(at)aldis.org.uk
-----Original Message-----
From: owner-xsi(at)Softimage.COM
[mailto:owner-xsi(at)Softimage.COM] On Behalf Of Bernard Lebel
Sent: 31 May 2005 22:09
To: XSI(at)Softimage.COM
Subject: Re: Elliptical filtering
Brad: elliptical filtering is necessary to take advantage of
the multi-resolution of the pyramidal map file. Otherwise the
maximum resolution is always the one lookedup by mental ray
(thus more memory).
Alan: I also suspect network issue, although as you said,
such a dramatic increase in render time is quite strange.
Bernard
On 5/31/05, Alan Jones <skyphyr(at)gmail.com> wrote:
Maybe with that render time a lot of it's reading the files off the
disk? Pulling the .pic into memory then uncompressing it
within memory
may be signicantly faster. Though I wouldn't expect it to
make such a
huge difference.
That's the only guess that comes to mind though sorry.
Cheers,
Alan.
On 5/31/05, Brad Friedman <xsibrad(at)fie.us> wrote:
This is a question more than an answer:
Why convert to pyramid if you're going to use elliptical
filtering?
I thought the two were entirely different types of
filters. Or can
elliptical filtering take advantage of a pyramid texture?
-brad
Bernard Lebel wrote:
Hi,
I am baffled at something. I have a scene with rather large
textures (3500x3500 and higher). In Pic format, it
renders in 45 seconds.
So I'm looking to save render time, and memory while
we're at it,
so I convert textures to pyramidal map float files (imf_copy -p
[...] map rgba_fp).
Then I turn on elliptical filtering, set the Maximum Pixels for
Minimum Radius to a low value 1.3, because higher than that is
generally not necessary.
In the past, I got much faster render times. However
right now the
render time explodes: it's at least 5 times longer than
with the
Pic version.
Any idea?
Thanks
Bernard
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