[ODE] RE: gjk convex collision preview for ODE

Wed Sep 7 08:58:29 MST 2005

How about collision between convex solids and general trimesh (including
concave trimesh i.e. terrain) ? Is it possible/difficult to implement? I
don't know much about GJK and neighter about how actual ODE trimesh
colliders work, so sorry if it's silly question.

Jaroslav

> -----Original Message-----
> From: Megan Fox [mailto:shalinor at gmail.com]
> Sent: Tuesday, September 06, 2005 10:56 PM
> To: phpbb at erwincoumans.com
> Cc: Rodrigo Hernandez; Jaroslav Sinecky
> Subject: Re: gjk convex collision preview for ODE
>
>
> That's great news - granted, you can "kinda" fake  convex solids, but
> it's just really irritating to make something that can roll AND settle
> on a side without them.
>
> Boulders look kinda silly no matter if I use boxes or spheres :(
> Never mind all those cylinder objects that never stop rolling.
>
> On 9/6/05, phpbb at erwincoumans.com <phpbb at erwincoumans.com> wrote:
> >
> > Hi Megan,
> >
> > This is just a 2 day integration job, and the problems are
> related to ode
> > integration, not to the gjk implementation. If I get the time, and
> > motivation there will be fast convex collision detection. Bunny
> was a very
> > bad example to show convex by the way :)
> >
> > Cheers,
> > Erwin
> >
> >
> >
> > Megan Fox writes:
> >
> > > Are the issues (like the bunny penetrating the ground) all solvable
> > > issues, or is GJK always going to have these sorts of issues?  Or are
> > > they more a problem with proper ODE integration?
> > >
> > > That is... at some point in the future, can we expect convex solids to
> > > be as stable as boxes and spheres, without a severe performence
> > > penalty?
> > >
> > >> Hi,
> > >>
> > >> Thanks!
> > >>
> > >> Indeed, the cylinders gain a bit of energy due to
> penetration depth recovery
> > >> in the ODE solver. It needs a little bit of damping, then it
> should be fine.
> > >> You can press 'n' as well, for a convex hull bunny. Bad
> example obviously,
> > >> to add 400+ vertices to a convex hull object. The graphics
> drawing of the
> > >> bunny seems to be very slow too. Also notice that there is
> interaction
> > >> between capped cylinder, box, sphere and gjk cylinder/convex
> hull too. In
> > >> gjk you can just take the convex-hull of two spheres for the capped
> > >> cylinder.
> > >>
> > >>
> > >> The modified ODE source code and Bullet source code can be
> downloaded here,
> > >> including visual studio 6 and 8 projectfiles:
> > >> http://207.234.235.180/ftp/pub/test/physics
> > >>
> > >> See a file called BulletWithOdeSampleIntegration.zip
> > >>
> > >> Open \Bullet\Extras\ode-0.5\VC6\Samples\MakeAllTests.dsw (or
> .sln for VC8)
> > >>
> > >> Thanks for testing !
> > >> Erwin
> > >>
> > >>
> > >> Megan Fox writes:
> > >>
> > >> > Yep, works fine now - looks great.  The cylinders are excellent,
> > >> > though it does seem as if they tend to gain velocity when
> rolling on
> > >> > their side (they sort of accelerate off into the distance
> and fall off
> > >> > the ground plane)
> > >> >
> > >> > On 9/6/05, phpbb at erwincoumans.com <phpbb at erwincoumans.com> wrote:
> > >> >>
> > >> >> Hi,
> > >> >>
> > >> >> this was a difficult to spot problem, related to Visual
> Studio 2005.
> > >> >> Apparently when it converts the vc6 files, it enables a
> 'manifest', and it
> > >> >> requires to add the file Microsoft.VC80.CRT.manifest and
> some dll's.
> > >> >>
> > >> >> I disabled this 'manifest' setting (whatever it means)
> and recompiled again.
> > >> >> I think this should work.
> > >> >>
> > >> >>
> http://207.234.235.180/ftp/pub/test/index.php?dir=physics/&file=bu
> lletgjk_od
> > >> >> e.zip
> > >> >>
> > >> >> Can you let me know ?
> > >> >>
> > >> >> Usage: press 'l' for bullet gjk cylinder, 'f' for gjk
> box, 'b' for ode box,
> > >> >> c and s. 't' for contact points (regular ode demo).
> > >> >>
> > >> >> Thanks,
> > >> >> Erwin
> > >> >>
> > >> >> Megan Fox writes:
> > >> >>
> > >> >> > Still no dice, at least for me.  Still complains of improper
> > >> >> > application configuration (an error I've never seen,
> oddly enough -
> > >> >> > I'm used to illegal operations and such)
> > >> >> >
> > >> >> > On 9/6/05, Erwin Coumans <erwin at erwincoumans.com> wrote:
> > >> >> >>
> > >> >> >> Hi,
> > >> >> >>
> > >> >> >> thanks for testing. I added one missing dll, msvcr80.dll.
> > >> >> >>
> > >> >> >> Could you check if it works, and if not, mail me which
> file is missing ? I'm
> > >> >> >> using visual studio 8, this might explain the problem.
> > >> >> >>
> > >> >> >> If it works, please mail at the ode forum ;)
> > >> >> >>
> > >> >> >> Thanks,
> > >> >> >> Erwin
> > >> >> >>
> > >> >> >> ----- Original Message -----
> > >> >> >> From: "Megan Fox" <shalinor at gmail.com>
> > >> >> >> To: "Erwin Coumans" <erwin at erwincoumans.com>
> > >> >> >> Cc: <ODE at q12.org>
> > >> >> >> Sent: Tuesday, September 06, 2005 1:32 AM
> > >> >> >> Subject: Re: [ODE] gjk convex collision preview for ODE
> > >> >> >>
> > >> >> >>
> > >> >> >> This is wonderful news... but when I attempt to run
> the exe, I get a
> > >> >> >> "this application is configured improperly" error.
> Alas.  Any ideas?
> > >> >> >>
> > >> >> >> ... I remain extremely excited at the prospect of
> convex collision, though.
> > >> >> >>
> > >> >> >> On 9/5/05, Erwin Coumans <erwin at erwincoumans.com> wrote:
> > >> >> >> >
> > >> >> >> > Hi,
> > >> >> >> >
> > >> >> >> > There is a small preview of Bullet GJK Convex
> Collision Detection
> > >> >> >> integrated
> > >> >> >> > with Open Dynamics Engine (ODE). Press l for a
> bullet gjk cylinder, f for
> > >> >> >> a
> > >> >> >> > bullet gjk box, b, s and c for ode colliders. Other
> convex primitives like
> > >> >> >> > cone, convex mesh etc. are a matter of adding
> graphics drawstuff for ODE.
> > >> >> >> > Disclaimer: it doesn't work perfect ;)
> > >> >> >> >
> > >> >> >> >
> > >> >> >>
> http://207.234.235.180/ftp/pub/test/index.php?dir=physics/&file=bu
lletgjk_ode.zip
> >> >> >> >
> >> >> >> > Sources are checked into CVS at
> >> >> >> > http://sourceforge.net/projects/bullet
> >> >> >> > Actual ODE demo source will be added soon.
> >> >> >> >
> >> >> >> > Erwin
> >> >> >> > http://www.continuousphysics.com/Bullet
> >> >> >> >
> >> >> >> > _______________________________________________
> >> >> >> > ODE mailing list
> >> >> >> > ODE at q12.org
> >> >> >> > http://q12.org/mailman/listinfo/ode
> >> >> >> >
> >> >> >> >
> >> >> >> >
> >> >> >>
> >> >> >>
> >> >> >> --
> >> >> >> -Megan Fox
> >> >> >> Lead Developer, Elium Project
> >> >> >> http://www.elium.tk
> >> >> >>
> >> >> >>
> >> >> >>
> >> >> >
> >> >> >
> >> >> > --
> >> >> > -Megan Fox
> >> >> > Lead Developer, Elium Project
> >> >> > http://www.elium.tk
> >> >>
> >> >>
> >> >>
> >> >
> >> >
> >> > --
> >> > -Megan Fox
> >> > Lead Developer, Elium Project
> >> > http://www.elium.tk
> >>
> >>
> >>
> >
> >
> > --
> > -Megan Fox
> > Lead Developer, Elium Project
> > http://www.elium.tk
>
>
>

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