[RC5] film rendering

Matthew Gabeler-Lee msg2 at po.cwru.edu
Sat Jan 23 21:13:27 EST 1999

"Scott I. Remick" wrote:

> What if it wasn't done in whole frames per user, but bunches of pixels?
> You would fetch the 3D model only once per frame, and then the
> "pixelserver" would give you a range of pixels to crunch out.  Multiple
> people could all be working on the same frame at once.  You'd only download
> a new model once your frame was finished.

hmmm....sounds like a good idea, but there's one problem.  Fancy 3d models can
be many megabytes for the model itself.  Someone on a modem would still only
be able to participate if they told it to connect and download at night, or
some other time when they were not using the connection....unless there is
some way of determining how much of a dialup connection is being used, and
thus duplicating the 'only run in idle time' on the internet connection as
well as the CPU.

> One could also come up with a way to not have to transfer the entire 3D
> model again for each frame.  If it were just made up of objects, you'd
> download the whole object library first, then for each frame you'd just
> need layout data for those objects.  Or maybe a diff method where all you
> download is how the objects in this frame have changed since the previous.
> This would mean sequencial progression through the frames but that's fine.
> And if you fall behind and the next frame is 3 ahead, then you download the
> 3 diffs and now you're on the proper frame.

That sounds like a good idea!  That's kind of the same idea the MPEG video
compression uses, or at least one of them.  Only store the compressed
differences between one frame and the next (In MPEG's case, I believe it can
store the differences in reverse order, although obviously not over more than
a couple frames).
That would remove a significant amount of the required downloading time, but
it might make it feasible for someone on a 56k dialup....if you're on a 28.8,
it still might be rather a load on the connection, and there are a lot of
people out there who pay for their dialup by the hour, or at least by the hour
if they go over a certain amount of time.  It might be useful to be able to
tell the client not to spend more than a certain amount of time connected of
its own accord per month.

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