[ODE] Slow performence in a given scene - optimizable, or "just how it is"?

[Megan Fox]

Eh, there's presently a lot of inner-collision between the trigger
bodies on a given entity (arms vs torso vs legs vs head vs sword hit
zones), and that's dead easy to optimize out... it's just that 246
doesn't seem terribly extreme for a larger scene, with piles of random
boxes and such - and I still need that level of scene to run better
than this.  Never mind that the larger scene would have dynamics going
as well, vs the present almost-no-dynamics-at-all-just-collisions
scene.

On 11/5/05, Geoff Carlton <gcarlton at iinet.net.au> wrote:
> Just on the face of it, 246 callbacks for 9 bodies seems alot.  Either
> its picking up static-static collisions, or else you've got almost 30
> geom primitives knocking around each active body.  If its the latter
> case, I'd think about condensing it into a static trimesh, or exploiting
> game knowledge to get a better partioning scheme than one of the
> standard ones.
>
> Geoff
>
> Megan Fox wrote:
>
> >Hrm... surprising results - I'd always though the total number of
> >calls was larger than the number that actually go through.
> >
> >Profiling says that, yes, in the "bad" collision case, the total
> >number of calls to my collision callback more than double.  However,
> >that's still only, in this case, 246 calls, as compared to 145 in the
> >"better" case.  These numbers seem a lot smaller than what I thought
> >it would take to bring the system down.
> >
> >
> >Does this seem right?  Is 246 collision callback calls, with a
> >stepsize of 0.016 and 5 quickstep iters, in a world with very, very
> >few actual dynamics objects (9 physical bodies total) enough to bring
> >the system down like this?  Or am I seeing a problem elsewhere?
> >
> >(this is on an Athlon 64 2800+ - and the bad case is enough to bring
> >me down to unplayably jumpy FPS)
> >
> >On 11/3/05, Jon Watte (ODE) <hplus-ode at mindcontrol.org> wrote:
> >
> >
> >>My first instinct would be to bake the collision of all static things
> >>into a single static mesh (or a few, block-sized, static meshes).
> >>
> >>Another thing you can do is to add profiling code to count how many
> >>near-callbacks you get, and store information about what attempts to
> >>collide with what, and plot that. That should show you some spikes.
> >>
> >>Characters and other complex systems should probably be in their own
> >>spaces (spaces can be hierarchical), so that they can be quickly culled
> >>when not colliding with other entities.
> >>
> >>Last, I would absolutely use a profiler to figure out where the most of
> >>the time is being spent. That would also guide me into making whatever
> >>optimizations necessary.
> >>
> >>Cheers,
> >>
> >>                       / h+
> >>
> >>
> >>Megan Fox wrote:
> >>
> >>
> >>>Alright, I'm coming up against a performence problem in a semi-dense
> >>>scene.  Semi-dense because, while there are a lot of objects in the
> >>>world, it really isn't all that "dense"... it's just a desert with
> >>>rocks and a single building.  I'm trying to determine if this is
> >>>expected/normal, or if I can bail myself out in some fashion.
> >>>
> >>>
> >>
> >>
> >
> >
> >--
> >-Megan Fox
> >Lead Developer, Elium Project
> >http://www.elium.tk
> >
> >_______________________________________________
> >ODE mailing list
> >ODE at q12.org
> >http://q12.org/mailman/listinfo/ode
> >
> >
> >
> _______________________________________________
> ODE mailing list
> ODE at q12.org
> http://q12.org/mailman/listinfo/ode
>


--
-Megan Fox
Lead Developer, Elium Project
http://www.elium.tk