Re: [Algorithms] Speculative Contacts

[Paul F. <pa...@wi...>]

> This is pretty cool! Thanks for sharing.

No probs :)

> What I've found when doing the "remove velocity" thing in the past (sweeping
> spheres against trimeshes, mostly), is that the amount of bounce you get (if
> you have >0 restitution) varies randomly. The reason being that "almost all"
> versus "almost none" of the velocity will be removed for any given timestep,
> depending on how soon within the timestep the object will intersect the
> target.

I have to admit, i've never tried this solution with a physics engine
which supported non zero restitution - none of the games i've worked
on have called for it :)

> It's possible to hack with things like "assumed velocity" being remembered
> at the beginning of the time step -- do you have any thoughts on possibly
> better solutions?

I not totally sure - you could always calculate what the 'restitution
portion' of the resulting velocity would have been and then just add
that back on as a target in the constraint solver, but i've no idea if
that would actually work :)

> (There's also the discontinuity in motion from removing a random amount of
> time, but as you say -- you gotta stop somewhere ;-)

It ends up being less of a discontinuity and more like a relaxation of
the response over a couple of frames - the more iterations you run,
the more resolved the final solution as ever :)

Cheers, Paul.

-- 
Paul Firth
http://www.wildbunny.co.uk
http://www.facebook.com/WildbunnyLtd
email: pa...@wi...