Trajectory & collision detection of multiple objects help


    Apr 06 2006 | 3:08 pm
    I've been trying to do some simple physics simulations using
    jit.gl.sketch, using 2 spheres rolling around, sort of simulating 2
    balls on a pool table. Can anyone point me in the right direction of
    how to figure out the trajectory of the balls after colliding with each
    other? The collision detection is easy, but I can't figure out the
    math of how to bounce them in the proper direction after colliding.
    I've looked at the 'trajectory' patch from
    http://cicm.mshparisnord.net/dl/trajectory.htm but it's difficult to
    figure out what the heck is going on, as it's a very very thick patch.
    Has anyone on the list done anything like this they'd like to share?
    I'm interested in hitting or pushing one ball, calculating it's speed
    and angle, and applying that to the collision with another object to
    calculate the new trajectories of both objects, plus I'd like to add
    some real world variables, such as mass, friction, elasticity, and
    gravity.
    Thanks!!!
    Brian

    • Apr 07 2006 | 9:41 am
      The PMPD library will be your best friend!
      http://www.maxobjects.com/?v=libraries&id_library=81& ;requested=PMPD&operateur=AND& id_plateforme=0
      Originally made for PD, these objects have been ported for max (osX & win),
      but as most of help file are missing/unusable, and there are no example
      patches for max/jitter (there are help patches script-converted from PD
      patch. unclear and not very useful) I would really advice you to check the
      PD version first, (very easy, just open the doc/example/pmpd patches) justto understand how it works, and then try to patch in max.
      (there are a couple of max example in Ali Momeni (osX) max port :
      < http://www.cnmat.berkeley.edu/%7eali/share/max/pmpd/pmpd-for -max.sit >
      And I can post a couple of patches that do the kind of thing you're looking
      for (spheres on a 2D pool table, with bounce, friction, attraction,.). as
      soon as I will have bought a new HD, reinstalled everything and restored my
      backup files. cause I had a terrible HD crash this morning!
      You can have a look at this small video of a patch I made with PMPD objects:
      Have fun with PMPD (I did!)
      Mathieu Chamagne
      www.maxobjects.com
    • Apr 07 2006 | 2:11 pm
      Thanks Mathieu! I was playing with that too by the way, but I wasn't
      sure where to begin.
      I'd love to see some example patches.
      Brian
    • Apr 12 2006 | 9:35 am
      Here is an example of using the great PMPD library (Physical modelling) in
      max/Jitter to simulate balls on a pool table (2d environment - collision /
      friction / gravity / attraction...)
      Have fun !
      Mathieu Chamagne
      http://mathieu.chamagne.free.fr
      www.maxobjects.com
    • Apr 28 2006 | 5:19 pm
      Hi Mathieu,
      I've finally had a minute to check out your patch on your site. Very
      cool!!! Can I hire you to make a patch for me? I need something
      super simple, simpler than the patch (perhaps) you've already created.
      Here is what I'm working on:
      www.playoptix.com
      What I need is to add ability to kick a ball or 3d object around, but
      have to ability (like your patch) to add gravity, so I can use this on
      a wall too. I would like to be able to have the spheres rotate in the
      direction they are rolling too. I would also like to apply various
      textures to the balls, or use other 3d objects that are imported, which
      could be anything from light bulbs, to logos, or 3d heads. What do you
      think??? Interested? Where are you located?
      I'm working on this project with Peter Nyboer-I guess he is friends
      with Ali too. My Jitter knowledge is about at a moderate skill level
      to say the least. I'm better at making the stuff look good, than
      making it work properly.
      Thanks!
      Brian Dressel
      773-398-2772
    • Apr 28 2006 | 5:35 pm
      Sorry list and Matthieu,
      I accidently posted my last message to the list instead of Matthieu
      personally, but since it's out there, anyone interested in adding to
      the project, email me!
      brian@m1interactive.net
      Thanks!
      Brian