building 2-d stick figure model in Java w/inverse kin. and physics - Java-Games

This is a discussion on building 2-d stick figure model in Java w/inverse kin. and physics - Java-Games ; Hi, The subject says it all , but I'll try to be more specific. I'm trying to build a 2-d model of a simple (human) stick figure for a 2-d rock-climbing game I'm writing for fun in Java. I would ...

+ Reply to Thread
Results 1 to 6 of 6

building 2-d stick figure model in Java w/inverse kin. and physics

  1. Default building 2-d stick figure model in Java w/inverse kin. and physics

    Hi,

    The subject says it all , but I'll try to be more specific. I'm
    trying to build a 2-d model of a simple (human) stick figure for a 2-d
    rock-climbing game I'm writing for fun in Java. I would like to do it
    in a nice object-oriented way, but more importantly, I want to be able
    to do the following: keeping 2 feet and 1 hand fixed in position, I
    want to be able to grab the other hand and move it to an exact
    location, and have the body follow. The main constraints are: the
    limbs are not elastic, and the joints each have a range of motion that
    cannot be exceeded.

    I can see that when I move the right hand, often there will be an
    infinite number of possible "solutions" or positions of the rest of
    the body, so I will need additional constraints. Ideally, the other
    hand and feet will support the weight of the figure, and I will
    calculate the body position support the body and maximize efficiency
    (ie. so the 'climber' doesn't get tired quickly)

    I am not a mech. engineer, so I'm partly doing this as an exercise to
    learn how to model a 2-d figure and add "realistic" features, such as
    the inverse kinematics and also balance and various forces.

    I'd like to start with something simple that I can understand, so if
    anyone has simple examples that are similar, that would be helpful.
    Also, online tutorials or even just suggestions for how to "model"
    this figure would be useful. I'm pretty much a beginner, but
    interested in learning. I realize there is already a 3-d climbing
    game, and I also realize there is complex software to handle this
    stuff, but I'm interested in this ground-up approach, since I really
    want to learn as much as possible.

    Here is the basic configuration of the stick figure (open to slight
    modification):

    O
    _/|\_
    ^
    / \
    | |

    I.e. the "fixed points" are the hands and feet (except the one being
    moved by the user/player), and the points to be automatically
    positioned are the elbows, knees, "neck" (point where arms, head and
    torso join) and "hips" (point where legs and torso join) I would like
    to be able to pick any hand/foot and move it and have the rest of the
    body follow based on 'balance' and 'strength'.

    I think I am starting to understand that the position of each joint is
    subject to "limb" length, and then I have to impose these other
    constraints so that I end up minimizing/maximizing a function. I just
    don't quite know how to set that up.

    Pseudocode/general algorithm data-structure hints are very welcome
    too.

    Please email response.

    Thanks for your patience and any help or guidance!
    G

  2. Default Re: building 2-d stick figure model in Java w/inverse kin. and physics

    I don't know if this will be much help to you, but it seems related and is
    fun anyway:
    http://www.sodaplay.com/

    Mitch Berkson



  3. Default Re: building 2-d stick figure model in Java w/inverse kin. and physics

    On Sat, 27 Dec 2003 02:15:43 -0500, "Mitch Berkson"
    <mitch@bermita.com> wrote:

    >I don't know if this will be much help to you, but it seems related and is
    >fun anyway:
    >http://www.sodaplay.com/
    >
    >Mitch Berkson
    >

    That's really cool.

  4. Default Re: building 2-d stick figure model in Java w/inverse kin. and physics

    bob <thanatos@coldmail.nu> brightened my day with his incisive wit when
    in news:96eruvc83pn7jh0uod3t9smaj4fti2qntn@4ax.com he conjectured that:

    > On Sat, 27 Dec 2003 02:15:43 -0500, "Mitch Berkson"
    > <mitch@bermita.com> wrote:
    >
    >>I don't know if this will be much help to you, but it seems related
    >>and is fun anyway:
    >>http://www.sodaplay.com/
    >>
    >>Mitch Berkson
    >>

    > That's really cool.


    Thats the understatement of the year. Brilliantly simple and effective UI.
    Great modelling. Excellent!

  5. Default Re: building 2-d stick figure model in Java w/inverse kin. and physics

    Gazing across the alien landscape, mitty heard the tapocketa-tapocketa
    of the the soda straw legs of the enigmatic alien creatures...

    Walter Mitty <mitticus.remo.veme@yahoo.co.uk> wrote in message news:<Xns9460F56DA500waltermitty@127.0.0.1>...
    > bob <thanatos@coldmail.nu> brightened my day with his incisive wit when
    > in news:96eruvc83pn7jh0uod3t9smaj4fti2qntn@4ax.com he conjectured that:
    >
    > > On Sat, 27 Dec 2003 02:15:43 -0500, "Mitch Berkson"
    > > <mitch@bermita.com> wrote:
    > >
    > >>I don't know if this will be much help to you, but it seems related
    > >>and is fun anyway:
    > >>http://www.sodaplay.com/
    > >>
    > >>Mitch Berkson
    > >>

    > > That's really cool.

    >
    > Thats the understatement of the year. Brilliantly simple and effective UI.
    > Great modelling. Excellent!


  6. Default Re: building 2-d stick figure model in Java w/inverse kin. and physics

    but probably not useful for the original poster. Sodaplay is neat , and Im even
    considering that cyclic waveform control for custonizing walking animations --
    I did email the creator to add joints with 0 stretch/jiggle and or struts with no
    enlongation so that you could create more rigid structures with tie points in their
    middle (try making an armbone with muscles attached half way up ts length --
    the part beyond the midpoint will wobble like a hinge even if you make the whole
    bone an assembly of triangles for stability (real bones done bend much)


    for the problem originally posted :
    complication of pure 2d approach -- none of the body joints can be closer to the
    cliff than the arch length of the child limb ( I seem to recall lots of pix with
    rockclimbers with their cheeks up against the rock face...) Some kind
    of pseudo 3d constraints will be needed eventually to allow realistic movements
    (so it wont look like walking on knees/elboes up the wall)





    maniacal_engineer wrote:

    > Gazing across the alien landscape, mitty heard the tapocketa-tapocketa
    > of the the soda straw legs of the enigmatic alien creatures...
    >
    > Walter Mitty <mitticus.remo.veme@yahoo.co.uk> wrote in message news:<Xns9460F56DA500waltermitty@127.0.0.1>...
    > > bob <thanatos@coldmail.nu> brightened my day with his incisive wit when
    > > in news:96eruvc83pn7jh0uod3t9smaj4fti2qntn@4ax.com he conjectured that:
    > >
    > > > On Sat, 27 Dec 2003 02:15:43 -0500, "Mitch Berkson"
    > > > <mitch@bermita.com> wrote:
    > > >
    > > >>I don't know if this will be much help to you, but it seems related
    > > >>and is fun anyway:
    > > >>http://www.sodaplay.com/
    > > >>
    > > >>Mitch Berkson
    > > >>
    > > > That's really cool.

    > >
    > > Thats the understatement of the year. Brilliantly simple and effective UI.
    > > Great modelling. Excellent!



+ Reply to Thread

Similar Threads

  1. Re: python and a 2 gigs Usb Stick (pure pythonic stick)
    By Application Development in forum Python
    Replies: 0
    Last Post: 12-07-2007, 10:15 AM
  2. python and a 2 gigs Usb Stick (pure pythonic stick)
    By Application Development in forum Python
    Replies: 0
    Last Post: 12-07-2007, 10:00 AM
  3. 3D stick-model in MS Excel
    By Application Development in forum Graphics
    Replies: 0
    Last Post: 12-04-2006, 05:12 PM
  4. Java Physics Engine For Sale
    By Application Development in forum Java-Games
    Replies: 7
    Last Post: 09-04-2004, 01:40 PM
  5. finding 3d model of playmobile figure ??
    By Application Development in forum Graphics
    Replies: 1
    Last Post: 09-14-2003, 11:46 PM