[sldev] Havok4 Public Beta is here!

Dale Mahalko dmahalko at gmail.com
Sat Sep 29 19:18:01 PDT 2007


On 9/29/07, Dzonatas <dzonatas at dzonux.net> wrote:

> it finally lagged really bad where everybody couldn't move..



 It is possible for a high volume of inactive physical objects to create a
chain reaction leading to ultra-lag. This lagging can potentially be
triggered on a large scale, in a sim littered with hundreds of "sleeping"
physical prims, where the objects fell to the ground, settled, and their
physics processing turned off.

If someone were for example to detonate a shrapnel bomb blowing outwards in
all directions at very high force in a field of such sleeping objects, the
fast moving shrapnel pieces will strike and suddenly "wake up" all the
surrounding objects in one huge ever expanding lag burst. Each frame of
physics calculation blows the awakened objects further outward striking
still more objects that were previously sleeping, continuing on until
potentially thousands of objects are demanding collision calculation time,
spreading out from the bomb epicenter, whether down-LOD'd to cubes or not.

If you wait it out the objects will probably settle in a large circle around
the epicenter of the bomb explosion, and the lag goes away, but it may take
a very long time (minutes, hours) for the sim to grind the calculations
through those thousands of colliding objects until they settle.


Naturally of course some testing of this is needed, since I'm still working
from a Havok-1 view of things... ;-)

- Scalar Tardis / Dale Mahalko
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