3 Replies Latest reply on Jan 8, 2011 1:21 PM by Googolhz

    Runtime ik springs: child nodes break when a parent node is moved

    Googolhz Level 1

      There is something wrong with IK armature springs when used in runtime mode. Child nodes become disjointed with user interaction of parent nodes.


      Drag spring on right from different points to see bug here: http://gardenofpossibilities.org/flash/ik_spring_runtime_bug/spring_runtimebug.html


      I filed this as a bug, but wanted to mention it here in case others have a similar problem or anyone has a workaround:


      Steps to reproduce bug:

      1. Build simple movieclip based armature

      2. add springs to bones

      3. set armature to runtime and publish



      Armature child nodes become disjointed with user interaction of parent nodes. Same disjointed behavior occurs when armature is moved with actionscript 3 ik.mover.


      Expected results:

      Armature nodes should remain properly connected when user or actionscript 3 ik_mover moves any node.


      My Analysis:

      When springs are 0 (no spring) armature works correctly. It appears that the problem is caused by child nodes pivoting at parent node head, when they should actually pivot at parent node tail. Also, when armature becomes disjointed, dragging or moving tail node (furthest from root) restores joints.

      Please enlighten me on what is wrong, how to fix (if possible). If this is a documented bug, please provide a reference to it.