RE: [Algorithms] N-body processing

[Matthew M. <ma...@me...>]

Oops. The paper is at http://www.cs.unc.edu/~geom/SSV/

> -----Original Message-----
> From: gda...@li...
> [mailto:gda...@li...]On Behalf Of
> Matthew MacLaurin
> Sent: Friday, August 18, 2000 2:20 PM
> To: gda...@li...
> Subject: RE: [Algorithms] N-body processing
>
>
>
>
> > Matthew,
> > Err... I don't think swept volumes (as used in PQP) will help,
> > except for 4D
> > collision detection which is not what was worrying me :) But
> maybe I miss
> > you point.
> >
> > Dave,
> > Welcome. Stefan actually tried that approach, but later. Well, whatever.
> > Could you explain what would be the benefit of lozenges ? Especially a
> > lozenge-tree ?!
>
> Dave and I are talking about the same thing here. Swept sphere
> volumes give
> you tighter fits, faster interference rejection, and MUCH faster proximity
> queries than OBBs. Particularly important if you're trying to
> stave off the
> poly^2 tests. I assumed from your topic you were talking about N-Body
> dynamic simulation, for which fast proximity queries will be extremely
> helpful.
>
> (re-)Read the paper "Fast Proximity Queries with Swept Sphere Volumes" at:
>
> You'll be glad you did, unless I'm missing your point. ;^)
>
>
> >
> > /*
> > Pierre Terdiman       *   Home: p.t...@wa...
> > Software engineer    *   Zappy's Lair:  www.codercorner.com
> > */
> >
> > ----- Original Message -----
> > From: Dave Eberly <eb...@ma...>
> > To: <gda...@li...>
> > Sent: Friday, August 18, 2000 7:56 PM
> > Subject: Re: [Algorithms] N-body processing
> >
> >
> > > From: "Matthew MacLaurin" <ma...@me...>
> > > To: <gda...@li...>
> > > Sent: Friday, August 18, 2000 1:02 PM
> > > Subject: RE: [Algorithms] N-body processing
> > >
> > > > Hey! Check out the swept sphere stuff at UNC! It's the newest
> > thing I've
> > > > seen in a while for fast proximities and N-Body sim. Even more
> > interesting
> > > > is what they're using it for -- it appears ideally suited
> to huge poly
> > > > counts. I posted the link last week.
> > >
> > > I put swept sphere stuff into NetImmerse when UNC was
> > > starting to look into the topic as an alternative to using
> > > OBBs in a tree.  I had asked Stefan Gottschalk at his
> > > dissertation defense if he had considered such bounding
> > > volumes, but he indicated 'no'.  They work out quite well
> > > because they rely on squared-distance calculations that
> > > turn out to be less expensive (on average) to calculate
> > > than the separating axes, especially so in situations of
> > > close proximity.
> > >
> > > Code for building trees of spheres (points a specified
> > > distance from a point), capsules (points a specified
> > > distance from a line segment), and lozenges (points a
> > > specified distance from a rectangle) is at my site, the
> > > MgcContainment.html page.   I eventually plan on
> > > putting the code at my site for the collision detection,
> > > but it may take a couple of months.
> > >
> > > --
> > > Dave Eberly
> > > eb...@ma...
> > > http://www.magic-software.com
> > >
> > >
> > >
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