[ODE] Combing setpos'ed "ghost" bodies with a rigid central core? Doable?

[Megan Fox]

Forgive the strange topic, let me explain:

I want both accurate collisions that match up with the skinned mesh AND a
physically active character.  If I start setpos'ing active rigid bodies
around, all hell is going to break loose - but would it be practical for me
to setpos bodies around IF those bodies were considered "ghosts" by the rest
of the world?  (eg. they exist only as sensors to detect collision, never
adding contact joints themselves)

I would monitor the collision responses, and apply forces accordingly - it
wouldn't be 100% physically accurate, but enough to get sword swings being
interrupted if the player bashes a brick wall, knock boxes around if they
get bashed, register hits as valid if they strike the player's arm (which
would typically be a bit outside the central cylinder body), etc.  A rigid
box flying into an arm wouldn't result in anything (aside from maybe
assigning some damage to the owner entity), but it would probably hit the
central rigid body (and assign force to the player that way) as explained
below.

These "ghost" bodies would exist around a central rigid core, which behaves
just like anything else.  Hit it hard enough and send it flying, movement is
stopped by a heavy pile of stuff, ducking lowers the height it "hovers" at,
and so on - the standard "player as a sphere/cylinder" representation.


My concern is that I'm not sure what sort of body position persistence is
going on behind the scenes - how exactly the integrator is going to handle a
body jumping from point A to B.  Will it still break ODE to start setpos'ing
things around, even if I avoid the explosion problem by not adding any
contact joints?

-Megan Fox / "Shalinor"
Lead Developer, Elium Project (http://www.elium.tk)