[sldev] Havok4 Public Beta is here!

[Dale Mahalko]

Thanks very much for finally getting this out the door to us. However I can
see an apparant problem for machine builders that is going to require a new
LSL command.

> Physics Engine Overload And Level Of Detail (LOD)
> - The collision level of detail (LOD) of objects may change when the
physics engine lags (this is controlled by the Runtime Collision Control
System (RCCS))
>    o At the moment there is only one LOD below the highest level:
primitives collide like boxes
>    o Correct collision shapes will gradually return to normal when the
physics engine recovers (at a rate of one prim per physics engine timestep)
>    o When objects transition from static to dynamic their LOD will be
pre-emptively dropped and they will collide at the lower LOD until the RCCS
automagically raises it


As someone who builds lots of complex machines with spinning wheels, rotors,
impellers, and so forth, it isn't a good idea for the LOD to be able to
suddenly degrade from a cylinder to a cube without notifying the scripts.
This sudden uinannounced LOD changing will immediately jam the device where
the newly formed cube corners overlap where a cylinder or sphere was
previously curved.

Frequently I am building objects that closely gap the tolerance spacing
between objects, and suddenly swapping to a cube shape will only make the
collisions completely wrong and potentially even worse until the object
explodes.

We will need the ability to detect these physics LOD changes on the per-prim
or per-link-group level so that the scripts driving the impellers, etc, can
know there's a problem and can self-deactivate and go non-physical until the
LOD goes back up to normal. It's much better to simply sleep the movers
until the engine LOD returns to normal.

Also, some sort of visual indication of LOD degrading would be useful to
builders. In the beta sandboxes, how am I to know if the incorrect
interactions I see are due to actual bugs, or just the sim silently and
invisibly substituting cubes in place of all my cylinders and toruses?

- Scalar Tardis / Dale Mahalko
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