tyActorIK Helper

The tyActorIK helper can be used to define parts of an actor IK chain, for use with the actor IK collision solver. In order for the solver to consider an input tyActorIK helper to be in a valid state, it needs a root bone and at least one effector bone. Further effector bones, look-at objects and parent objects are optional.

IK root bone

  • IK root bone: the root bone is the top bone (top-most parent) of an IK chain.

Effector bones

  • Effector bones: the list of bones to be used as effectors for the chain by the IK solver.

IK effectors are what all bones in an IK chain attempt to point towards. If you specify multiple effectors in the list, the overall chain will be split into multiple sub-chains, each one with a single parent and single effector, which will be solved in hierarchical order. In order for effectors to be considered valid, they must be a child of the root bone (at any level of ancestry).

  • Affect orientation: when enabled, effector bones at the end of a chain will be oriented to match the rotate of the second last bone in the chain (using FK).

IK look-at

  • IK look-at: the object which will be used to orient the chain along the IK axis.

  • Blend distance: the minimum distance between an effector’s current position and its target position, between which the look-at influence will be interpolated. Increasing this value can prevent chains from snapping towards their look-at target once an IK collision takes place.

  • Max chain depth: controls how many levels of sub-chains will be affected by the IK look-at.

Sometimes you may define multiple effectors, but you may not want all of their sub-chains to be affected by the IK look-at. For example, you may define multiple effectors to create a leg connected directly to a foot and toe…but don’t want the foot/toe to be affected by the look-at. Lowering/increasing the chain depth value will allow you to tune exactly which sub-chains will be affected by the look-at (a value of 1 means only the first sub-chain will be affected).

  • Affect effectors: when enabled, effectors at the end of an IK chain will be affected by the look-at.

  • Match initial side: when enabled, chains initialing pointing in the opposite direction of a look-at will remain that way during the look-at solve.

Effector parent object

  • Effector parent object: the effector parent object is an optional object you can define which all effectors in the list will remain positionally relative to. The parent itself will be affected by the IK collision solver, which allows you to process all effector collisions as a group.

The effector parent is useful in situations where bones in an IK chain may not be positioned in a way that will produce proper collisions. For example, a Biped skeleton has a hinge at the ankle and toe of a foot, but no bones are positioned at the bottom of a foot…this means no collisions will happen at the bottom of a Biped’s foot, which is not very useful or intuitive. By placing an effector parent at the bottom of a Biped’s foot (and linking it to the foot in the scene), whenever that effector parent collides during the IK collision solve, it will affect the other effectors as well, moving them all together and creating more intuitive collisions.


  • Show icon: controls whether the tyActorIK icon is displayed in the viewport.

  • Icon size: controls the size of the tyActorIK icon.