[Opensim-dev] New MOSES Physics Video

[Ai Austin]

I saw the suggestion that explosion "physical" effects like this 
might be dealt with locally (e.g. in the same was as particle visual 
effects) in each viewer and not as a shared phenomenon where the 
position of all the parts are updated in everyone's viewer.

Snow and lighting visual effects often can be approximated and 
everyone has roughly the same sort of shared experience, modulo the 
allowable and supportable  graphical quality in each viewer..

I am reminded though of an exercise I took part in using the Forterra 
OLIVE when that was still being actively developed (I think it got 
sold to SAIC and I have not heard much aboit it since)...  it was a 
training exercise for military staff manning a checkpoint, and I was 
an observer through my avatar.  The military folks being trained were 
to watch fro suspicious activity, but also treat all people at the 
checkpoint well... and also to deal with the aftermath of an attack.. 
rescue helicopter coming in with dust clouds from the ground and 
all... it was very realistic.  And I was very surprised, even though 
my avatar was partially protected from the checkpoint area by a solid 
wall, that an explosion injured me... the pieces flying hiring my arm 
and me being rendered unconscious!  Viewer blurring over and me being 
almost out of it.

This is an example of the use of virtual worlds where the shared 
experience of what debris from an explosion goes and who it hits and 
when is necessary.  And I think may be typical of the sort of thing 
MOSES is seeking to achieve for realistic simulated 
training.  Interestingly Forterra OLIVE was itself originally 
developed on a project for the US Army also more than a decade ago.

Clearly there needs to be some consideration of the granularity of 
physics and position updates across all users that are present in the 
area and a consideration of how many parts of an exploding  object 
can be made physical and updates sent and at what rate.  This could 
be a simply enormous quantity of data and updates as others have 
pointed out... so its not surprising that more avatars leads to 
slower performance.  Crashes nonetheless indicates something that is amiss.