helge_h wrote:
> Here is my file and output; the only difference between the two sessions is the
> sphere radius - 1357 units makes finite objects that render fast, 1358 units
> makes infinite objects that render much slower, and also where there are no
> objects.

ok, the code behind this is a test in the parser's post-processing that
sets the infinite flag on any object whose volume exceeds a pre-defined
value; in the case of 3.6 and 3.7 this value is 10,000,000,000 (10^10).
the code itself was added in 1994.

there might have been several reasons behind this; one would probably be
related to bounding slab creation. there could be others (such as the
render-time performance of slabs with objects of such large volume present).

it's hard to say how much need there is for this today - if the reasoning
was to reduce the memory use of bounding slabs, then it's probably less
important than it used to be. if it was due to the efficiency of the
bounding, then it's not so clear, as the operation of bounding slabs has
not changed significantly.

one thing that would be worth looking into is whether or not this is needed
or desirable with +bm2 bounding. I suspect it is not.

if you're willing to do an analysis on a large sample of scenes using a
version of POV that allows this above-mentioned volume test to be disabled,
and compare the results to the same scenes without it disabled, then I'll
build a special EXE.

-- Chris

Post a reply to this message