inverse kinematics


    Apr 15 2007 | 2:34 pm
    hi all, been dabbling with inverse ik for fun.
    cant get it, i believe its something with my transform order in opengl.
    any help would be excellent.
    there are some resources on the net. the one i've followed.
    www.friendsofed.com/samples/1590595181.pdf
    i guess OO would be a better approach but i'd like to tackle this in plain
    max.

    • Apr 16 2007 | 3:29 pm
      I don't know a second thing about IK, but it sure is a fun patch to play around with.
      What exactly should the red arrow be doing, just follow the gray one?
    • Apr 16 2007 | 6:57 pm
      On Apr 15, 2007, at 10:34 AM, yair reshef wrote:
      > hi all, been dabbling with inverse ik for fun.
      > cant get it, i believe its something with my transform order in
      > opengl.
      > any help would be excellent.
      quick fix: swap sin and cos and it'll work (i.e. x=sin, y=cos)
      or... they did dy/dx in the pdf, and you did dx/dy in the patch...
      --
      Matthew Lewis
      Advanced Computing Center for the Arts and Design (ACCAD)
      The Ohio State University
    • Apr 17 2007 | 10:49 am
      that patch is fun.
      on a side note, I've been meaning to make a GUI widget that turns
      circular mouse movements into rotation information... so here it is
      based in part off of your patch. It's probably not the most
      efficient or correct way to do it, but it works!
      Called "Spinner.pat" - http://lowfrequency.org/interactivity/wiki/
      index.php?title=User:EvanR
      cheers
      evan
      On Apr 16, 2007, at 7:58 PM, Matthew Lewis wrote:
      > On Apr 15, 2007, at 10:34 AM, yair reshef wrote:
      >
      >> hi all, been dabbling with inverse ik for fun.
      >> cant get it, i believe its something with my transform order in
      >> opengl.
      >> any help would be excellent.
      >
      > quick fix: swap sin and cos and it'll work (i.e. x=sin, y=cos)
      > or... they did dy/dx in the pdf, and you did dx/dy in the patch...
      >
      > --
      > Matthew Lewis
      > Advanced Computing Center for the Arts and Design (ACCAD)
      > The Ohio State University
      > http://accad.osu.edu/~mlewis
      >
    • Apr 17 2007 | 3:45 pm
      thanks Matthew, i had a few problems with my syntax, and of course your fixes were in need.
      here is a revised patch. most of this stuff can be subpatched...
    • Apr 17 2007 | 7:20 pm
      fantastic!
      thanks for sharing,
      nesa
      On Apr 17, 2007, at 5:45 PM, yair reshef wrote:
      > #P
    • Apr 17 2007 | 8:05 pm
      yeah, it's really a sexy little bit of Jitter code - yair, I might be
      crazy, but I seem to recall a youtube video of you controlling a jitter
      object with an accelerometer of sorts?!? - it looked like a red kite
      with a long tail, and using this code to build on that would be awesome.
      Andreas.
      nesa skrev:
      > fantastic!
      >
      > thanks for sharing,
      > nesa
      >
      > On Apr 17, 2007, at 5:45 PM, yair reshef wrote:
      >
      >> #P
      >
      > .
      >
    • Apr 18 2007 | 1:09 pm
      i posted an update but the forum rejected it, mybe the list also.
      first, thanks for the kind words guys.
      Andreas, the method i used in the video was getting the position of the tracker and pushing the previous positions down a matrix, then used wes line2quad to opengl it.
      here it is, cuz watching is fun.
      http://www.youtube.com/watch?v=FvWerivk3UE -this is a bit rough
      i tracked a conductor baton and made a nice simple polygon trail of his motion, it turned out nice.
      at the end i didn't use the accelerometer (sensetive) but 2 position-synced unibrain cameras , one with an IR filter and the other without.
      the first for tracking the ir led and the other for color video
      here is the footage+patch
    • Apr 18 2007 | 1:14 pm
      and this is a poly~ version for the ik patch.
      i had a problem with poly,
      taking the output of a poly and sending it into the next poly.
      used sprintf, thispoly~, and forward - but i would be happy to hear of a better way.
    • Apr 18 2007 | 1:44 pm
      >
      > here is the footage+patch
      > http://art2please.com/upload/max/tracker/
      >
      This appears to be down...
    • Apr 18 2007 | 9:41 pm
      i followed thru with the code, previous was still forward kinematics, reel
      ik is this.
      it works bbut more work is needed before i can make the number of limbs
      dynamic.
      its hard to "loop backwards" in max, as is called for this to work.
      btw. david, its on my home server, please try again.
      On 4/18/07, david vandenbogaerde wrote:
      >
      > here is the footage+patch
      > > http://art2please.com/upload/max/tracker/
      > >
      >
      > This appears to be down...
      >
      >
      >
      >
    • Apr 18 2007 | 11:30 pm
      Very cool!
      tim
    • Apr 19 2007 | 1:52 pm
      great work man, very elegant. imagine what this could do when attached to the end of a certain conductors wand...
      -n
    • Apr 19 2007 | 2:41 pm
      nadav, you owe the list a certain patch dont u? ;)