[opensource-dev] Serious regression in SSB-enabled regions

[Henri Beauchamp]

On Thu, 07 Mar 2013 15:53:03 +0100, Thomas Shikami wrote:

> Is there even a requirement zo have Z-offset be in the avatar
> appearance message?

The Z-offset is not transmitted to the server by the viewers
implementing it: what is transmitted is the sum of the Z-offset (which
can also be negative) and the avatar height as calculated from the
shoes and shape visual parameters. This causes the server to think
that the avatar is either taller or smaller while its shape and shoes
didn't change, but which also causes the animations to be played at a
higher or lower level above the floor (the server can auto-correct
properly standing animations for any worn shape or shoes, but of
course this auto-correction algorithm fails for sitting, kneeling,
laying, crouching, crawling anims since in those the feet to hip
length doesn't count for the same fraction as in standing anims).

In short, the viewer transmits to the server what it computed to be
the proper "avatar height" for the animation to be correctly leveled
with the floor; the server then adopts this new height, applies its
own auto-correction (the one that was designed for standing anims)
and relays the info to all viewers, making the avatar appear at the
proper level for everyone around.

> To me it looks more like that hip-offset would be better suited 
> to be in some animation parameter, which makes it incompatible with 
> older viewers, but a SSB-enabled simulator might translate that 
> animation parameter into an avatar appearance message for viewers not 
> supporting that idea of animation parameter.

I already replied to this suggestion to Satomi Ahn in this list,
explaining why it won't work properly and won't allow to perform the
equivalent operations as what non-SSB servers have been allowing since
day one of SL (and OpenSim).

Ideally, yes, the animations should have allowed to enter the "reference
height" (the height of the avatar for which the anim is properly leveled
with the floor) and "scalar" (the scalar to apply to the difference
between the reference height and the current height of the avatar playing
the anim so to find the Z-offset to add to this latter height so to allow
a proper leveling with the floor).

However, all existing anims would still fail to play properly if LL was
to add these parameters now without supporting the Z-offset feature.

This is not the solution we need, even if adding such parameters to the
anims could be a future improvement (but you will always need Z-offet
support for all the existing anims, as well as for correcting manually
the sit target of pose-balls/furniture not having a scripted anim height
adjustment).

Henri.