RE: [Algorithms] Simple Air Resistance Simulation for Shells
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From: Hansen, D. <Dan...@di...> - 2002-09-18 08:20:48
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Has anyone parametricized the velocity and position taking air-resistance into consideration. I.e v(t) = v0 + a * t p(t) = p0 + (v0 + 0.5 * a * t) * t ..could be used when there's no air-resistance. I'd like something similar with air-resistance. I've seen some formulas with alot of nasty exponents in them, I'm looking for a simpler hack. Anyone? -----Original Message----- From: Charles Bloom [mailto:cb...@cb...] Sent: den 11 september 2002 07:58 To: gda...@li... Subject: RE: [Algorithms] Simple Air Resistance Simulation for Shells This "midpoint method" is 2nd order Runge-Kutta. See, for example : http://www.sst.ph.ic.ac.uk/angus/Lectures/compphys/node11.html http://csep1.phy.ornl.gov/ode/node7.html The traditional so-called "Runge-Kutta method" is the 4th order method. Anyway, all silliness, but some of the stuff on the web is pretty good. At 12:19 AM 9/11/2002 -0400, ja...@jn... wrote: >Thanks to all. Using the midpoint method combined with a small enough time >step appears to provide a reasonable amount of accuracy for my use. I'll >keep Runge-Kutta in mind for future use if it proves necessary. > >Jack > >-----Original Message----- >From: Chris Butcher (BUNGIE) [mailto:cbu...@mi...] >Sent: Monday, September 09, 2002 2:52 PM >To: Jon Watte; ja...@jn...; gda...@li... >Subject: RE: [Algorithms] Simple Air Resistance Simulation for Shells > > >Even using something as simple as the midpoint method (a second-order >integrator) will give much better results for minimal effort. Runge-Kutta >is probably overkill... ? > >v_intermediate= v - 0.5*k(v^2)t; >v_final= v - k(v_intermediate^2)t; > >-- >Chris Butcher >Rendering & Simulation Lead >Halo 2 | Bungie Studios >bu...@bu... > > >-----Original Message----- >From: Jon Watte [mailto:hp...@mi...] >Sent: Monday, September 09, 2002 12:43 >To: ja...@jn...; gda...@li... >Subject: RE: [Algorithms] Simple Air Resistance Simulation for Shells > > >> I'm trying to do a simple ballistics model for shells. The formula I'm >> using is: >> >> v' = v - k(v^2)t; > >This is a first-order Euler integrator (I believe). These are known >to be unstable at any time step -- as you notice :-) > >The typical answer when faced with numerical integration problems >is to turn to a fourth-order Runge-Kutta integrator. I'm sure if you >plug that into Google, you'll get a massive number of hits. It might >show up on MathWorld, too. > >Cheers, > > / h+ > > > > >-------------------------------------------------------------------- >mail2web - Check your email from the web at >http://mail2web.com/ . > > > > >------------------------------------------------------- >In remembrance >www.osdn.com/911/ >_______________________________________________ >GDAlgorithms-list mailing list >GDA...@li... >https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list >Archives: >http://sourceforge.net/mailarchive/forum.php?forum_ida88 > ------------------------------------------------------- Charles Bloom cb...@cb... http://www.cbloom.com ------------------------------------------------------- In remembrance www.osdn.com/911/ _______________________________________________ GDAlgorithms-list mailing list GDA...@li... https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list Archives: http://sourceforge.net/mailarchive/forum.php?forum_id=6188 |