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Join To Prev IK Key
This IK constraint is used to specify if a footstep is sliding or planted. If Join
To Prev IK Key is on, then the biped foot maintains a reference position to
the previous key, keeping the foot planted. If Join To Prev IK Key is off during
a footstep, then the foot can be moved to a new position creating a sliding
footstep.
Join To Prev IK Key also functions to lock the biped hands in space. Use Set
Planted Key on the biped hands to lock their position in space.
TIP If you are having trouble with a foot or hand popping back to a previous
‘keyed’ position, check to make sure that the Join To Prev IK Key is off, especially
when you're using pivot points.
See also:
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Key Info Rollout on page 4367
Understanding Walk Cycle Constraints
Walking motions in both freeform and footstep animations should follow the
rules of certain IK constraints. In both freeform and footstep animation, a
footstep interval is the start and end of a sequence of IK constraints in world
space, with IK Blend set to be greater than 0.0. A biped foot in the Move state
should have body space turned on with an IK Blend of 0.0. By using these IK
constraints, you can convert between the two animation methods seamlessly.
In a freeform walking animation, typically you need two key types for the
legs:
■ If the foot is planted on the ground, the key must have IK Blend=1.0 with
Object Space and Join To Prev Key turned on.
■ If the foot is in the air between footsteps, then IK Blend=0.0 with Body
Space turned on, and Join To Prev Key turned off.
In the course of creating a walk or run cycle, you need to alternate these IK
constraints for the feet. If the foot is sliding on the ground, then the IK
constraints are IK Blend=1.0 in Object Space with Join To Prev Key tuned off.
All of these IK parameters can be found on the Key Info rollout.
To speed up the process of applying these IK constraints, the Key Info rollout
has three additional set key buttons: Set Planted Key, Set Sliding Key, and Set
Freeform Animation | 4263