Hi all,

    I've some very strange behavior in POV on my WinNT system. Recently I've
been doing a lot of animation work and during the test runs I'm rendering at
small frames (50 X 50 pixels). For my current scene each frame takes about 1
or 2 seconds to parse and render so I see them clicking by pretty quickly.
Every once in a while, though, the scenes fly by much faster, at about 3
frames per second (my guess).
    The problem is that I don't know if they are really rendering that
quickly or if the message buffer is just backed up or something like that. I
do know that there is no change in the scenes at that point (i.e., the scene
doesn't get occluded by 1 object and therefore make the render much
simpler). Also there is no predictability or reproducability of this
phenomena.
    My only though is that this. I've also noticed that in NT the POV
process only uses a very small amount of the CPU, 2 or 3 percent, usually
(this is with all of the highest priority settings). If this stat is true
and it sometimes, for some reason, bumped up to using the full 100% as it
should, this would account for the extreme speed up.

    So, what seems reasonable? Well, when I render the animation I get about
1200 PPS, this is for the small size frames. If I render a single, large
frame (e.g., 1280 X 1024) then I get about 6500 PPS and the CPU usage goes
up to about 70 or 80%. If there was a way for the animation renderings to
continuously maintain the higher CPU usage and the higher PPS then that
would come close to accounting for the periodic speed up that I see.

    So, is there any way to maintain the high speed? Why, even on the large
frames, does POV only use 70 or 80% and not the full 100%? What do people
see on other systems, like Linux?


Thanks,

--Rainer


P.S. I actually have a dual CPU system and all of the CPU usage percentages
shown about are double the amount I see. I believe the above is what I would
see in a single CPU system.

Post a reply to this message